another emc resource from emc standards...helping you solve your emc problems 9 bracken view,...
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Helping you solve your EMC problems
9 Bracken View, Brocton, Stafford ST17 0TF T:+44 (0) 1785 660247 E:[email protected]
Another EMC resourcefrom EMC Standards
Complying with IEC/EN 61800-3 Good EMCEngineering Practices in the Installation of PowerDrive Syst
Com
plyi
ng w
ith IE
C/E
N 6
1800
-3G
ood
EMC
Eng
inee
ring
Prac
tices
in th
eIn
stal
latio
n of
Pow
er D
rive
Syst
ems
REO
UK
LTD
RE
O (U
K) L
TD, U
nits
2 -
4 C
allo
w H
ill R
oad,
Cra
ven
Arm
s B
usin
ess
Par
k, C
rave
n A
rms
Shr
opsh
ire S
Y7
8NT
Tel:
0158
8 67
3411
Fax
: 015
88 6
7271
8E
mai
l: sa
les@
reo.
co.u
k W
ebsi
te: w
ww
.reo.
co.u
k
11
Con
tent
s1.
Intro
duct
ion
22.
Wha
t is
not c
over
ed in
this
Gui
de7
3. C
ost i
mpl
icat
ions
94.
Em
issi
ons
175.
Imm
unity
546.
EM
C s
uppr
essi
on p
rodu
cts
from
RE
O56
7. R
efer
ence
s an
d fu
rther
read
ing
57
Com
plyi
ng w
ith IE
C/E
N 6
1800
-3—
Goo
d EM
C E
ngin
eerin
g Pr
actic
es in
the
Inst
alla
tion
of P
ower
Driv
e Sy
stem
s—
Kei
th A
rmst
rong
Che
rry
Clo
ugh
Con
sulta
nts,
ww
w.c
herr
yclo
ugh.
com
Fron
t and
bac
k co
ver p
ictu
res
© J
orge
n U
dvan
g - i
stoc
kpho
to.c
om
23
IEC
924
/04
Cop
ied
from
Fig
ure
2 of
EN
/IEC
618
00-3
:200
4Fi
gure
2:
Defi
niti
ons
of P
DS,
CD
M a
nd B
DM
, sho
win
g th
e PD
S’s
“por
ts”
1. In
trod
uctio
nTh
is G
uide
is fo
r wha
t EN
/IEC
618
00-
3 [1
] cal
ls “P
ower
Driv
e S
yste
ms”
(P
DS
s), w
hich
are
AC
or D
C m
otor
sp
eed
cont
rol u
nits
mor
e us
ually
ca
lled
varia
ble
spee
d dr
ives
(VS
Ds)
or
adj
usta
ble
spee
d dr
ives
(AS
Ds)
. V
SD
s fo
r AC
mot
ors
only
are
ofte
n ca
lled
varia
ble
frequ
ency
driv
es
(VFD
s), a
djus
tabl
e fre
quen
cy d
rives
(A
FDs)
, or j
ust i
nver
ter d
rives
.
EN
618
00-3
is li
sted
und
er th
e E
MC
D
irect
ive
[2],
and
so m
ay b
e us
ed fo
r de
clar
ing
PD
Ss
in c
onfo
rmity
with
it.
At t
he ti
me
of w
ritin
g, th
e E
MC
D
irect
ive
has
been
app
lyin
g its
200
4 ve
rsio
n [1
] sin
ce th
e 1s
t Oct
ober
20
07, w
hich
mea
ns th
at a
ll P
DS
s su
pplie
d in
the
EU
sin
ce th
en s
houl
d lis
t EN
618
00-3
:200
4 on
thei
r EU
D
ecla
ratio
ns o
f Con
form
ity, a
nd
prov
ide
the
appr
opria
te te
st e
vide
nce
in th
eir “
Tech
nica
l Doc
umen
tatio
n Fi
le”
– if
they
are
follo
win
g th
e “s
tand
ards
ro
ute
to c
onfo
rmity
” (se
e [3
]).
EN
618
00-3
:200
4 is
iden
tical
to IE
C
6180
0-3:
2004
, so
this
Gui
de is
equ
ally
ap
plic
able
out
side
of t
he E
urop
ean
Uni
on (E
U) w
here
the
IEC
ver
sion
–
or s
ome
natio
nal s
tand
ard
base
d up
on it
– is
app
lied.
Eve
n w
here
ther
e ar
e no
lega
l EM
C
requ
irem
ents
, com
plyi
ng w
ith E
N/IE
C
6180
0-3
is g
ood
engi
neer
ing
prac
tice
that
will
hel
p im
prov
e pr
ofi ts
ove
rall,
ov
er th
e m
ediu
m a
nd lo
ng te
rm,
Inst
alla
tion
or p
art o
f ins
talla
tion
Pow
er D
rive
Sys
tem
s (P
DS
)
CD
M (C
ompl
ete
Driv
e M
odul
e)
Mot
or a
nd S
enso
rs
Driv
en e
quip
men
t
Sys
tem
con
trol
and
sequ
enci
ngB
DM
(Bas
ic D
rive
Mod
ule)
Con
trol
conv
erte
ran
d pr
otec
tion
Feed
ing
sect
ion
Fiel
d su
pply
dyna
mic
bra
king
Aux
illia
ries,
oth
ers
.....
IEC
923
/04
e.g.
a s
yste
m w
ithin
an in
stal
latio
n
Cop
ied
from
Fig
ure
1of
EN
/IEC
618
00-3
:200
4
Figu
re 1
: D
efi n
ition
s of
PD
S, C
DM
and
BD
M
and
will
als
o he
lp in
crea
se c
usto
mer
co
nfi d
ence
and
mar
ket s
hare
.
1.1.
The
defi
niti
on o
f a P
DS
Acc
ordi
ng to
EN
/IEC
618
00-3
[1],
a P
DS
is a
n ad
just
able
spe
ed A
C o
r D
C m
otor
driv
e, c
onsi
stin
g of
a b
asic
dr
ive
mod
ule
(BD
M),
whi
ch is
par
t of
the
com
plet
e dr
ive
mod
ule
(CD
M),
whi
ch –
whe
n co
nnec
ted
to it
s m
otor
–
beco
mes
a P
DS
, whi
ch in
turn
is
part
of a
sys
tem
or i
nsta
llatio
n, a
s sh
own
in F
igur
e 1.
IEC
618
00-1
, IE
C 6
1800
-2 a
nd IE
C
6180
0-4
prov
ide
the
deta
ils fo
r the
de
fi niti
ons
used
in F
igur
es 1
and
2.
If th
e P
DS
has
its
own
dedi
cate
d tra
nsfo
rmer
, thi
s tra
nsfo
rmer
is
incl
uded
as
a pa
rt of
its
CD
M.
A no
n-ex
haus
tive
list o
f PD
S
appl
icat
ions
incl
udes
:
Mac
hine
tool
s, ro
bots
, tes
t eq
uipm
ent i
n pr
oduc
tion,
test
be
nche
s;P
aper
mac
hine
s, te
xtile
pro
duct
ion
mac
hine
, cal
ende
rs in
the
rubb
er
indu
stry
;P
roce
ss li
nes
in p
last
ic in
dust
ries
or in
met
al in
dust
ries,
rolli
ng m
ills;
Cem
ent c
rush
ing
mac
hine
s,
cem
ent k
ilns,
mix
ers,
cen
trifu
ges,
ex
trusi
on m
achi
nes;
Dril
ling
mac
hine
s;C
onve
yors
, mat
eria
l han
dlin
g m
achi
nes,
hoi
stin
g eq
uipm
ent
(cra
nes,
gan
tries
, etc
.);
Pro
puls
ion
of s
hips
, etc
. (bu
t not
tra
ctio
n dr
ives
or e
lect
ric v
ehic
les)
;P
umps
, fan
s, e
tc.
The
PD
Ss
may
be
conn
ecte
d to
ei
ther
indu
stria
l or p
ublic
mai
ns p
ower
di
strib
utio
n ne
twor
ks. A
n “in
dust
rial
netw
ork”
is c
onsi
dere
d to
be
one
that
is s
uppl
ied
by a
ded
icat
ed h
igh
volta
ge (H
V) d
istri
butio
n tra
nsfo
rmer
, or
its
own
gene
rato
r, w
hich
sup
plie
s on
ly in
dust
rial c
usto
mer
s or
, for
ex
ampl
e a
ship
or o
ffsho
re d
rillin
g rig
.
A pu
blic
pow
er d
istri
butio
n ne
twor
k is
on
e th
at o
pera
tes
at lo
w v
olta
ges
(e.g
. 11
5/23
0/40
0V) a
nd s
uppl
ies
dom
estic
pr
emis
es. T
hese
net
wor
ks u
sual
ly
have
an
earth
ed (g
roun
ded)
neu
tral.
Whe
re a
n in
dust
rial s
ite is
pow
ered
fro
m a
low
vol
tage
mai
ns p
ower
di
strib
utio
n, a
s so
met
imes
hap
pens
, th
e m
ains
dis
tribu
tion
netw
ork
on th
at
site
is tr
eate
d as
a p
ublic
net
wor
k.
As
Figu
re 1
sho
ws,
a P
DS
may
driv
e so
me
equi
pmen
t (e.
g. a
win
ch, p
ump,
Figu
re 2
sho
ws
anot
her v
iew
of a
P
DS
, thi
s tim
e id
entif
ying
the
vario
us
“por
ts” t
hat a
re te
sted
by
[1].
45
fan,
etc
.), a
nd/o
r be
part
of a
sys
tem
, an
d/or
be
part
of a
n in
stal
latio
n, b
ut
only
the
PD
S is
cov
ered
by
EN
/IEC
61
800-
3 (s
ee 1
.3).
1.2.
Th
e re
quire
men
ts o
f EN
/IEC
618
00-3
[1] i
nclu
des
requ
irem
ents
for P
DS
s w
ith B
DM
inp
ut a
nd/o
r out
put
volta
ges
(line
-to-li
ne) o
f up
to 3
5 kV
A
C rm
s, ra
ted
from
a fe
w h
undr
ed
wat
ts to
hun
dred
s of
MW
, ins
talle
d in
re
side
ntia
l, co
mm
erci
al o
r ind
ustri
al
loca
tions
.
It cl
aim
s to
ach
ieve
EM
C fo
r suc
h ap
plic
atio
ns (b
ut s
ee 1
.3) b
ut w
arns
th
at it
can
not c
over
ext
rem
e ca
ses
that
cou
ld o
ccur
(but
whi
ch a
re
assu
med
to h
ave
an e
xtre
mel
y lo
w
prob
abili
ty).
It al
so w
arns
that
it d
oes
not c
over
the
EM
C p
erfo
rman
ce in
the
case
of f
aults
occ
urrin
g, w
hich
is v
ery
rele
vant
for s
ectio
n 2.
4 la
ter i
n th
is
Gui
de.
[1] s
peci
fi es
emis
sion
s lim
its,
imm
unity
leve
ls, a
nd te
st m
etho
ds
for a
PD
S a
ccor
ding
to it
s in
tend
ed
appl
icat
ion
and
the
com
pete
ncy
of
its in
stal
ler.
It do
es th
is b
y de
fi nin
g tw
o di
ffere
nt e
lect
rom
agne
tic
“env
ironm
ents
” or l
ocat
ions
, and
fo
ur d
iffer
ent “
Cat
egor
ies”
of i
nsta
ller
com
pete
ncy,
as
disc
usse
d be
low
.
1.2.
1. T
he F
irst E
nviro
nmen
tTh
is e
nviro
nmen
t inc
lude
s do
mes
tic
prem
ises
, and
est
ablis
hmen
ts d
irect
ly
conn
ecte
d w
ithou
t int
erm
edia
te
trans
form
ers
to a
low
-vol
tage
pow
er
supp
ly n
etw
ork
whi
ch s
uppl
ies
build
ings
use
d fo
r dom
estic
pur
pose
s.
Hou
ses,
apa
rtmen
ts, c
omm
erci
al
prem
ises
or o
ffi ce
s in
a re
side
ntia
l bu
ildin
g ar
e ex
ampl
es o
f Firs
t E
nviro
nmen
t loc
atio
ns.
1.2.
2. T
he S
econ
d En
viro
nmen
tTh
is e
nviro
nmen
t inc
lude
s al
l es
tabl
ishm
ents
oth
er th
an th
ose
dire
ctly
con
nect
ed to
a lo
w v
olta
ge
mai
ns p
ower
sup
ply
netw
ork
whi
ch
supp
lies
build
ings
use
d fo
r dom
estic
pu
rpos
es.
Indu
stria
l are
as, a
nd te
chni
cal a
reas
of
any
bui
ldin
g th
at a
re fe
d fro
m
thei
r ow
n de
dica
ted
trans
form
er a
re
exam
ples
of S
econ
d E
nviro
nmen
t lo
catio
ns.
1.2.
3. C
ateg
ory
C1
This
cat
egor
y is
for P
DS
s w
ith ra
ted
volta
ge le
ss th
an 1
,000
V, in
tend
ed
for u
se in
the
Firs
t Env
ironm
ent,
perm
itted
to b
e in
stal
led
by a
nyon
e.
1.2.
4. C
ateg
ory
C2
This
cat
egor
y is
for P
DS
s w
ith ra
ted
volta
ge le
ss th
an 1
,000
V, w
hich
is
neith
er a
plu
g-in
dev
ice
nor a
mov
able
de
vice
and
, whe
n us
ed in
the
Firs
t
Env
ironm
ent,
is in
tend
ed to
be
inst
alle
d an
d co
mm
issi
oned
onl
y by
a
“pro
fess
iona
l”.
A pr
ofes
sion
al is
defi
ned
as
a pe
rson
or a
n or
gani
satio
n ha
ving
ne
cess
ary
skill
s in
inst
allin
g an
d/or
co
mm
issi
onin
g P
DS
s, in
clud
ing
thei
r E
MC
asp
ects
.
1.2.
5. C
ateg
ory
C3
This
app
lies
to P
DS
s of
rate
d vo
ltage
le
ss th
an 1
,000
V, i
nten
ded
for u
se
in th
e S
econ
d E
nviro
nmen
t and
no
t int
ende
d fo
r use
in th
e Fi
rst
Env
ironm
ent,
perm
itted
to b
e in
stal
led
by a
nyon
e.
1.2.
6. C
ateg
ory
C4
This
app
lies
to P
DS
s of
rate
d vo
ltage
eq
ual t
o or
abo
ve 1
,000
V, o
r rat
ed
curr
ent e
qual
to o
r abo
ve 4
00A
, or
inte
nded
for u
se in
com
plex
sys
tem
s in
the
Sec
ond
Env
ironm
ent,
perm
itted
to
be
inst
alle
d by
any
one.
1.3.
Em
issi
ons
and
imm
unity
of
PD
Ss a
s pa
rt o
f sys
tem
s or
in
stal
latio
nsA
s m
entio
ned
abov
e, a
PD
S m
ay
be a
par
t of a
sys
tem
, or p
art o
f an
inst
alla
tion,
but
EN
/IEC
618
00-3
[1]
only
cov
ers
the
PD
S it
self.
How
ever
, for
com
plia
nce
with
th
e E
MC
Dire
ctiv
e, c
usto
mer
sp
ecifi
catio
ns, o
r jus
t goo
d E
MC
engi
neer
ing
prac
tices
, the
ent
ire
syst
em o
r par
t of a
n in
stal
latio
n m
ay
be c
over
ed b
y ot
her E
MC
sta
ndar
ds
– m
ost l
ikel
y th
e ge
neric
sta
ndar
ds:
EN
/IEC
610
00-6
-1, i
mm
unity
re
quire
men
ts fo
r res
iden
tial,
com
mer
cial
and
ligh
t ind
ustri
al
envi
ronm
ents
EN
/IEC
610
00-6
-2, i
mm
unity
re
quire
men
ts fo
r the
indu
stria
l en
viro
nmen
tE
N/IE
C 6
1000
-6-3
, em
issi
ons
requ
irem
ents
for r
esid
entia
l, co
mm
erci
al a
nd li
ght i
ndus
trial
en
viro
nmen
tsE
N/IE
C 6
1000
-6-4
, em
issi
ons
requ
irem
ents
for t
he in
dust
rial
envi
ronm
ent
In th
is c
ase,
it is
pos
sibl
e fo
r a P
DS
th
at is
com
plia
nt w
ith [1
] to
caus
e th
e sy
stem
or i
nsta
llatio
n th
at it
is
part
of to
fail
to c
ompl
y w
ith th
e E
MC
st
anda
rds
that
app
ly to
it. T
here
are
tw
o re
ason
s w
hy th
is c
ould
occ
ur:
a) T
he e
mis
sion
s pe
rmitt
ed b
y [1
] for
th
e P
DS
mig
ht e
xcee
d th
e em
issi
ons
limits
per
mitt
ed b
y ot
her s
tand
ards
for
the
syst
em o
r ins
talla
tion
cont
aini
ng
the
PD
S. F
or e
xam
ple,
som
e lim
its
that
are
per
mitt
ed b
y [1
] for
som
e P
DS
Cat
egor
ies
exce
ed th
e lim
its
perm
itted
by
the
appr
opria
te g
ener
ic
stan
dard
for t
he s
ame
type
of
envi
ronm
ent b
y m
ore
than
20d
B.
b) T
here
may
be
seve
ral P
DS
s in
one
sy
stem
(e.g
. the
sau
sage
mac
hine
in
67
2. W
hat i
s no
t cov
ered
in th
is G
uide
2.1.
Tes
ting
toEN
/IEC
618
00-3
This
Gui
de is
onl
y co
ncer
ned
with
th
e us
e of
goo
d E
MC
eng
inee
ring
inst
alla
tion
prac
tices
to h
elp
PD
Ss
com
ply
with
EN
/IEC
618
00-3
[1],
it do
es n
ot c
over
the
actu
al te
stin
g te
chni
ques
that
are
use
d by
[1].
RE
O h
ave
seve
ntee
n G
uide
s [4
] tha
t de
tail
how
to a
ctua
lly p
erfo
rm th
e va
rious
test
s re
quire
d by
[1],
incl
udin
g th
e si
tuat
ion
whe
re th
e te
st c
anno
t be
car
ried
out a
t a “c
ontro
lled
EM
C
site
”, su
ch a
s in
side
a te
st la
bora
tory
’s
anec
hoic
cha
mbe
r.
[1] a
lso
incl
udes
gui
danc
e on
wha
t to
do
whe
n te
stin
g ha
s to
be
done
on
-site
, or w
hen
the
mai
ns c
urre
nt
requ
ired
by a
PD
S e
xcee
ds 1
00A
. If
furth
er g
uida
nce
is re
quire
d on
on-
site
te
stin
g, [5
] may
pro
ve u
sefu
l.
2.2.
Com
plyi
ng w
ith th
e EM
C
Dire
ctiv
eIt
is n
ot th
e ai
m o
f thi
s G
uide
to
disc
uss
how
a m
anuf
actu
rer s
houl
d go
ab
out l
egal
ly c
ompl
ying
with
the
EM
C
Dire
ctiv
e [2
] [6]
, as
impl
emen
ted
in th
e va
rious
nat
iona
l law
s of
the
Eur
opea
n U
nion
’s (E
U’s
) Mem
ber S
tate
s, s
uch
as [7
] [8]
for t
he U
nite
d K
ingd
om (U
K).
The
com
plia
nce
met
hods
that
are
av
aila
ble
are
disc
usse
d in
[3].
2.3.
Hum
an H
ealth
and
Sa
fety
The
very
hig
h vo
ltage
s an
d cu
rren
ts
asso
ciat
ed w
ith h
igh-
pow
er P
DS
s ca
n ca
use
a va
riety
of p
robl
ems
for
heal
th a
nd s
afet
y. E
N 6
1800
-5-1
[l]
cove
rs e
lect
rical
, the
rmal
and
ene
rgy
haza
rds
of P
DS
s, b
ut d
oes
not c
over
hu
man
hea
lth e
ffect
s du
e to
exp
osur
e to
ele
ctric
and
/or m
agne
tic fi
elds
(E
MFs
).
All
PD
Ss
that
dec
lare
com
plia
nce
with
th
e Lo
w V
olta
ge D
irect
ive
[9] m
ust
also
now
dec
lare
com
plia
nce
with
the
EM
F R
egul
atio
ns [1
0]. W
hile
ther
e ar
e no
EM
F st
anda
rds
spec
ifi ca
lly fo
r P
DS
s, it
will
pro
babl
y be
bes
t to
appl
y th
e “g
ener
ic E
MF
stan
dard
” EN
623
11
[11]
.
A w
orkp
lace
Hea
lth a
nd S
afet
y D
irect
ive
on E
MF
also
exi
sts
[12]
, bu
t at t
he ti
me
of w
ritin
g is
not
fully
in
forc
e. L
ike
all H
ealth
and
Saf
ety
dire
ctiv
es, i
t app
lies
to th
e ow
ners
/us
ers
of a
site
or t
he e
quip
men
t on
it,
and
not t
o m
anuf
actu
rers
who
sup
ply
them
with
equ
ipm
ent.
Nei
ther
of t
hese
issu
es a
re d
iscu
ssed
fu
rther
in th
is G
uide
.
Figu
re 3
), an
d si
nce
thei
r em
issi
ons
will
add
up
they
cou
ld e
xcee
d th
e lim
its fo
r the
ove
rall
syst
em o
r in
stal
latio
n.
It w
as b
ecau
se o
f a) t
hat t
he
Eur
opea
n A
ssoc
iatio
n of
Com
pete
nt
Bod
ies
(EC
AC
B, d
isba
nded
si
nce
2004
/108
/EC
, has
repl
aced
C
ompe
tent
Bod
ies
with
Not
ifi ed
Bod
ies
and
chan
ged
the
com
plia
nce
met
hods
, see
[3])
com
plai
ned
to th
e E
urop
ean
Com
mis
sion
(EC
) abo
ut
the
listin
g of
EN
618
00-3
und
er th
e E
MC
Dire
ctiv
e, a
nd a
sked
that
it b
e re
mov
ed fr
om th
at li
st. I
t was
not
re
mov
ed, b
ut s
hortl
y af
terw
ards
the
EC
em
ploy
ed a
n E
MC
Con
sulta
nt w
ith
the
aim
of e
nsur
ing
they
did
not
mak
e su
ch e
mba
rras
sing
mis
take
s ag
ain.
Figu
re 3
: Exa
mpl
e of
a m
achi
ne w
ith a
num
ber o
f PD
SsPa
rt o
f a c
ompl
ex in
stal
latio
n....
The
cont
rol c
ubic
le fo
r the
sau
sage
mac
hine
inst
alle
d at
Sto
rk T
owns
end
B.V
., Th
e N
ethe
rland
s, in
200
6. 1
0 m
etre
s lo
ng; 6
0 va
riabl
e sp
eed
driv
es 1
8 m
ulti-
axis
ser
vo d
rives
89
3. C
ost i
mpl
icat
ions
3.1.
The
EM
C o
f PD
Ss,
fi nan
cial
risk
s, a
nd th
e pe
rils
of s
hort
-term
ism
It is
qui
te p
ract
ical
to d
esig
n a
BD
M
(see
2.6
) so
that
any
PD
S u
sing
it is
gu
aran
teed
to c
ompl
y w
ith E
N/IE
C
6180
0-3
(and
the
EM
C D
irect
ive)
re
gard
less
of h
ow it
is in
stal
led
and
how
the
PD
S th
at e
mpl
oys
it is
co
nfi g
ured
. How
ever
, suc
h B
DM
s w
ill
alm
ost c
erta
inly
cos
t mor
e.
Whe
n us
ing
such
a B
DM
, a
man
ufac
ture
r who
inte
grat
es it
into
a
PD
S th
at h
e se
lls to
an
end-
user
(o
r the
ir m
ain
cont
ract
or) w
ill b
e ab
le
to d
emon
stra
te c
ompl
ianc
e w
ith th
e E
MC
Dire
ctiv
e [2
] [7]
with
out h
avin
g to
test
to E
N/IE
C 6
1800
-3. A
ll th
ey
will
nee
d to
do
is to
incl
ude
a fe
w
verifi
ed
EM
C d
ocum
ents
from
the
BD
M m
anuf
actu
rer,
in th
eir T
echn
ical
D
ocum
enta
tion
File
[3].
Suc
h P
DS
s w
ill b
e la
rgel
y un
affe
cted
by
EM
I in
thei
r ope
ratio
nal
envi
ronm
ent,
and
so w
ill g
ener
ally
op
erat
e w
ith g
reat
er p
reci
sion
. Whe
n us
ed in
man
ufac
turin
g pr
oces
ses
they
of
ten
impr
ove
yiel
ds a
nd q
ualit
y, a
nd
they
ofte
n pr
ove
to b
e m
ore
relia
ble.
A
ll th
is w
ill re
duce
thei
r ove
rall
cost
-of
-ow
ners
hip
for t
heir
user
s, a
nd a
lso
gene
rally
redu
ce th
e w
arra
nty
cost
s fo
r the
ir m
anuf
actu
rers
, som
etim
es
very
sig
nifi c
antly
.
Suc
h go
od E
MC
des
ign
incr
ease
s th
e bi
ll-of
-mat
eria
ls (B
OM
) cos
t of t
he
BD
M, a
nd m
ost m
anuf
actu
rers
wou
ld
assu
me
that
they
mus
t the
refo
re s
ell
it fo
r a h
ighe
r pric
e. B
ut th
is is
not
ne
cess
arily
the
case
, bec
ause
(for
ex
ampl
e) th
eir p
rodu
ct c
ould
hav
e lo
wer
war
rant
y co
sts,
and
/or m
ight
win
a
muc
h la
rger
mar
ket s
hare
bec
ause
of
its
ease
of u
se [2
3]. S
o th
ey m
ight
m
ake
as m
uch
or m
ore
profi
t ev
en
whe
n se
lling
it fo
r the
sam
e pr
ice
as
a m
ore
typi
cal B
DM
that
doe
s no
t co
ntro
l EM
C s
o w
ell a
nd s
o re
quire
s an
y P
DS
it is
use
d in
to g
o th
roug
h co
stly
test
s to
EN
/IEC
618
00-3
, to
be a
ble
to s
how
due
dili
genc
e in
co
mpl
ying
with
the
EM
C D
irect
ive.
This
all
soun
ds g
ood,
but
it ra
rely
ha
ppen
s in
real
life
bec
ause
of s
hort-
term
ism
– m
anag
ers
usua
lly o
nly
look
ah
ead
as fa
r as
the
next
qua
rter’s
fi n
anci
al fi
gure
s –
so e
ven
very
si
gnifi
cant
pos
sibi
litie
s fo
r med
ium
and
lo
ng-te
rm fi
nanc
ial g
ains
, im
prov
ing
profi
tabi
lity
and
retu
rn-o
n-in
vest
men
t (R
OI)
are
igno
red.
Som
etim
es th
e be
nefi t
s of
inve
stin
g in
goo
d E
MC
en
gine
erin
g ar
e di
scou
nted
bec
ause
of
a la
ck o
f app
reci
atio
n of
EM
C
issu
es.
Sho
rt-te
rmis
m m
eans
that
buy
ers
are
look
ing
for t
he c
heap
est B
DM
, and
of
ten
deci
de s
olel
y on
the
basi
s of
cr
ude
“kW
ver
sus
£” c
ompa
rison
s.
For t
his
reas
on, a
nd o
ther
s, m
ost
BD
M m
anuf
actu
rers
’ sal
esm
en fe
el
2.4.
Fun
ctio
nal S
afet
yIt
is a
lso
not t
he a
im o
f thi
s G
uide
to
dis
cuss
the
Func
tiona
l Saf
ety
issu
es o
f PD
Ss,
oth
er th
an to
sa
y th
at s
ince
ele
ctro
mag
netic
in
terfe
renc
e (E
MI)
can
caus
e P
DS
s to
suf
fer e
rror
s or
mal
func
tions
(e.g
. un
com
man
ded
chan
ges
in s
peed
, to
rque
, dire
ctio
n, e
tc.)
– w
here
thes
e co
uld
have
con
sequ
ence
s fo
r saf
ety
risks
, com
plyi
ng w
ith E
N 6
1800
-3
or a
ny o
ther
EM
C te
st s
tand
ards
, ev
en m
ilita
ry o
r aer
ospa
ce o
nes,
is
insu
ffi ci
ent f
or e
stab
lishi
ng a
def
ence
of
due
dili
genc
e.
EN
618
00-5
-2 [1
3] a
pplie
s th
e ba
sic
stan
dard
on
Func
tiona
l Saf
ety
EN
61
508
[14]
to P
DS
s, b
ut –
like
[14]
–
does
not
pre
scrib
e w
hat t
o do
abo
ut
the
poss
ibili
ty o
f EM
I. E
MI c
an c
ause
a
varie
ty o
f pro
blem
s fo
r mot
or d
rives
, w
hich
mig
ht b
e co
stly
(e.g
. dow
ntim
e)
or h
ave
safe
ty ri
sks,
as
show
n by
so
me
of th
e re
al-li
fe a
necd
otes
in [1
5].
To c
over
EM
I it i
s ne
cess
ary
to
appl
y th
e ba
sic
stan
dard
on
EM
C
for F
unct
iona
l Saf
ety
[16]
, for
whi
ch
the
IET
have
pro
duce
d a
help
ful
and
prac
tical
9-s
tep
man
agem
ent
proc
edur
e [1
7]. E
MC
test
s ha
ve a
role
to
pla
y in
due
dili
genc
e fo
r saf
ety,
but
th
ey c
anno
t be
suffi
cien
t on
thei
r ow
n.
2.5.
Mac
hine
ry S
afet
yA
PD
S a
s de
fi ned
by
the
EN
618
00
serie
s of
sta
ndar
ds is
not
a m
achi
ne
as d
efi n
ed b
y th
e M
achi
nery
Saf
ety
Dire
ctiv
e [1
8], a
nd s
o th
is d
irect
ive
does
not
app
ly to
PD
Ss.
Of c
ours
e, s
yste
m in
tegr
ator
s an
d ow
ners
of fi
xed
inst
alla
tions
(usi
ng th
e de
fi niti
on in
[2] a
nd [7
]) w
ill o
ften
use
a P
DS
to p
rovi
de th
e m
otiv
e po
wer
fo
r a m
achi
ne th
at d
oes
com
e un
der
the
Mac
hine
ry D
irect
ive,
or o
ne o
f the
H
ealth
and
Saf
ety
at W
ork
Dire
ctiv
es,
in w
hich
cas
e it
is im
porta
nt th
at th
ey
unde
rsta
nd th
e po
ints
mad
e in
2.3
and
2.
4. T
hey
will
fi nd
hel
pful
info
rmat
ion
on E
MC
in [1
9] [2
0] a
nd [1
7].
2.6.
Ele
ctro
nic
and
mec
hani
cal d
esig
n of
bas
ic
driv
e m
odul
es (B
DM
s)Th
is G
uide
doe
s no
t cov
er th
e el
ectro
nic
and
mec
hani
cal d
esig
n an
d as
sem
bly
of th
e B
DM
sec
tion
of P
DS
s, o
r its
cab
inet
or o
ther
en
clos
ure.
But
wel
l-pro
ven
tech
niqu
es
do e
xist
for t
hese
EM
C a
spec
ts o
f B
DM
s, s
ee [2
1] [2
2] a
nd [2
0].
1011
reck
on th
at a
s m
any
as o
ne-th
ird o
f all
PC
sof
twar
e “c
rash
es” a
re c
ause
d by
E
MI.
We
have
all
expe
rienc
ed th
ese
reco
vera
ble
cras
hes
on o
ur P
Cs
but
how
man
y of
us
have
iden
tifi e
d th
e cr
ash
as a
n E
MI i
ncid
ent a
nd b
roug
ht
it to
the
atte
ntio
n of
the
peop
le w
ho
sit o
n th
e IE
C c
omm
ittee
for c
ompu
ter
EM
C s
tand
ards
?
Ano
ther
issu
e is
that
ther
e is
a ra
pid
incr
ease
in e
lect
roni
c in
stru
men
tatio
n,
cont
rol a
nd c
omm
unic
atio
ns in
all
area
s of
hum
an a
ctiv
ity, i
nclu
ding
sa
fety
-rel
ated
sys
tem
s, a
ll br
ough
t ab
out b
y th
e co
ntin
ual r
educ
tion
in th
e co
sts
of s
emic
ondu
ctor
s (tr
ansi
stor
s).
Als
o, th
e re
duct
ion
in c
osts
of
sem
icon
duct
ors
is b
roug
ht a
bout
by
mak
ing
them
phy
sica
lly s
mal
ler a
nd
oper
atin
g th
em o
n lo
wer
vol
tage
s.
A st
ate-
of-th
e-ar
t mic
ropr
oces
sor
(a “s
ilico
n ch
ip” o
n a
prin
ted
circ
uit b
oard
) at t
he e
nd o
f 200
8 co
uld
cont
ain
as m
any
as 1
bill
ion
sem
icon
duct
ors
and
oper
ate
from
0.
9V D
C p
ower
. It i
s un
fortu
nate
bu
t una
void
able
that
thes
e tre
nds
inev
itabl
y m
ake
them
mor
e su
scep
tible
to E
MI.
This
rapi
d in
crea
se in
ele
ctro
nic
com
plex
ity, p
lus
the
wor
seni
ng o
f el
ectro
nic
imm
unity
, mig
ht re
veal
that
P
DS
s pr
evio
usly
thou
ght t
o be
EM
C
com
plia
nt (b
ecau
se o
f no
com
plai
nts)
w
ere
not s
o, in
fact
. It w
ould
be
a gr
eat p
ity if
the
fi rst
tim
e th
is w
as
disc
over
ed w
as a
n in
cide
nt th
at
invo
lved
a s
erio
us in
jury
or d
eath
(see
2.
4).
In a
ny a
rea
whe
re e
lect
roni
c te
chno
logi
es a
re u
sed,
the
past
is n
ot
a re
liabl
e gu
ide
to th
e fu
ture
.
The
fact
that
ther
e is
no
evid
ence
of
a p
robl
em s
houl
d ne
ver b
e ta
ken
as p
rovi
ng th
at th
eref
ore
ther
e is
no
pro
blem
. Alth
ough
it s
ound
s at
fi r
st li
ke a
reas
onab
le a
rgum
ent,
it ha
s be
en k
now
n si
nce
the
late
18t
h ce
ntur
y th
at is
not
a lo
gica
l con
clus
ion
to m
ake
(see
[25]
). It
is v
ery
disa
ppoi
ntin
g to
fi nd
suc
h an
obv
ious
er
ror i
n an
IEC
sta
ndar
d.
3.3.
Out
put fi
lter
s an
d in
dust
rial P
DSs
Very
few
PD
Ss
use
outp
ut fi
lters
be
caus
e of
thei
r cos
t, bu
t eve
n if
we
igno
re E
MC
issu
es, w
e ha
ve to
ac
know
ledg
e th
at –
with
out o
utpu
t fi l
ters
– h
igh-
pow
er V
SD
s su
ffer f
rom
hi
gh le
vels
of c
omm
on-m
ode
(CM
) cu
rren
t (se
e 4.
2) fl
owin
g th
roug
h th
eir
bear
ings
, whi
ch c
an s
horte
n th
eir l
ife
by a
s m
uch
as te
nfol
d.
Ano
ther
pro
blem
is th
at w
here
long
m
otor
cab
les
are
used
, the
“Far
aday
E
ffect
” cau
ses
the
mot
or’s
driv
e vo
ltage
s to
rise
sig
nifi c
antly
hig
her
than
thos
e ou
tput
by
the
VS
D, w
hich
ca
n de
grad
e th
e in
sula
tion
mat
eria
ls
in th
e ca
bles
and
mot
or w
indi
ngs,
ag
ain
lead
ing
to e
arly
failu
re a
nd
incr
ease
d do
wnt
ime.
may
be
unw
illin
g or
una
ble
to s
ell
a m
ore
cost
ly p
rodu
ct o
n th
e ba
sis
of lo
wer
ove
rall
cost
-of-o
wne
rshi
p,
espe
cial
ly in
regi
ons
of th
e w
orld
w
here
EM
C re
gula
tions
are
not
m
anda
tory
or s
trict
ly e
nfor
ced.
It i
sn’t
help
ed b
y th
e fa
ct th
at m
ost e
ngin
eers
ha
ve d
iffi c
ulty
in p
rese
ntin
g te
chni
cal
argu
men
ts fo
r im
prov
ed p
rofi t
abili
ty
and
RO
I in
a fi n
anci
al m
anne
r tha
t ca
n be
und
erst
ood
by th
e pe
ople
who
ru
n th
eir c
ompa
nies
. Som
e re
med
ies
for t
his
latte
r pro
blem
will
be
foun
d in
[2
4].
The
inev
itabl
e re
sult
of th
is is
that
, in
gen
eral
, BD
M m
anuf
actu
rers
ai
m to
mak
e th
e ch
eape
st p
rodu
cts
they
pos
sibl
y ca
n, w
hich
incr
ease
s th
e co
st a
nd ti
me
burd
ens
for t
he
syst
em in
tegr
ator
s an
d ow
ners
of
fi xed
inst
alla
tions
(as
defi n
ed in
[2],
see
[3]),
who
use
thei
r pro
duct
s to
co
nstru
ct P
DS
s. T
hese
com
pani
es
have
to u
se d
esig
n an
d in
stal
latio
n te
chni
ques
as
desc
ribed
in th
is G
uide
, an
d pe
rform
cos
tly te
stin
g to
EN
/IEC
61
800-
3 on
eac
h P
DS
they
mak
e (s
omet
imes
test
ing
on-s
ite),
to b
e ab
le
to d
ecla
re c
ompl
ianc
e to
the
EM
C
Dire
ctiv
e. T
his
incr
ease
s th
eir o
vera
ll co
sts
and
so s
igni
fi can
tly in
crea
ses
the
pric
e th
at th
ey h
ave
to c
harg
e to
thei
r cus
tom
ers,
abo
ve w
hat t
hey
wou
ld h
ave
to c
harg
e if
they
cou
ld
buy
BD
Ms
that
had
bee
n de
sign
ed
appr
opria
tely.
3.2.
Mai
ns fi
lters
and
in
dust
rial P
DSs
Acc
ordi
ng to
cla
use
D.1
.2.2
in A
nnex
D
of [
1], t
he c
omm
on p
ract
ice
for
man
y ye
ars
has
been
to in
stal
l PD
Ss
with
out m
ains
fi lte
rs. I
t cla
ims
that
the
gene
ral l
ack
of c
ompl
aint
s ab
out r
adio
in
terfe
renc
e fro
m s
uch
inst
alla
tions
in
dica
tes
that
they
ach
ieve
EM
C –
but
th
is is
a v
ery
risky
ass
umpt
ion
to
mak
e.
Ther
e ar
e m
any
reas
ons
why
peo
ple
mig
ht n
ot c
ompl
ain
abou
t int
erfe
renc
e,
why
they
mig
ht n
ot b
e ab
le to
iden
tify
whe
re it
cam
e fro
m, w
hy e
nfor
cem
ent
auth
oriti
es m
ight
not
hav
e th
e re
sour
ces
or e
xper
tise
to in
vest
igat
e,
or w
hy s
uch
inve
stig
atio
ns w
ere
not
repo
rted
to (o
r rem
embe
red
by) t
he
peop
le w
ho w
rote
[1].
Als
o, th
ere
is
ofte
n an
ele
men
t of (
bad)
luck
in m
any
EM
I inc
iden
ts, w
hich
tend
s to
mak
e th
em h
ard
to re
prod
uce
at w
ill, o
ften
mak
ing
EM
I har
d to
“pro
ve” a
fter a
n in
cide
nt.
I fi n
d th
at m
any
peop
le w
ho c
laim
th
eir s
yste
ms
or in
stal
latio
ns d
on’t
have
EM
I pro
blem
s, a
ctua
lly d
on’t
unde
rsta
nd h
ow to
iden
tify
an E
MI
prob
lem
any
way
(if t
hey
have
eve
n he
ard
of it
). Th
ey m
ay h
ave
suffe
red
(or b
e su
fferin
g) fr
om p
robl
ems
that
ar
e de
crea
sing
yie
lds
or in
crea
sing
do
wnt
ime
– bu
t the
y ne
ver r
ecog
nise
d th
em a
s be
ing
caus
ed b
y E
MI.
For e
xam
ple,
som
e co
mpu
ter e
xper
ts
1213
EN
/IEC
618
00-3
onl
y sp
ecifi
es
limits
for c
ondu
cted
em
issi
ons
over
th
e fre
quen
cy ra
nge
150k
Hz
to
30M
Hz,
and
the
mac
hini
ng c
entre
m
et th
ese
limits
, but
sin
ce it
s dr
ive’
s sw
itchi
ng fr
eque
ncy
was
2kH
z it
emitt
ed s
igni
fi can
t lev
els
of s
witc
hing
ha
rmon
ic n
oise
into
its
mai
ns s
uppl
y fro
m 2
kHz
at 2
kHz
inte
rval
s al
l the
w
ay u
p to
150
kHz
and
beyo
nd. A
t 15
0kH
z an
d ab
ove
the
mai
ns fi
lter
fi tte
d to
the
PD
S a
ttenu
ated
the
nois
e em
issi
ons
to m
eet t
he s
peci
fi cat
ion,
bu
t it d
id n
ot p
rovi
de s
igni
fi can
t at
tenu
atio
n be
low
150
kHz.
All
mai
ns fi
lters
reso
nate
at s
ome
frequ
ency
(see
3.2
.9 o
f [21
], 8.
1.3.
1 of
[26]
or 5
.10
of [1
9]) a
nd s
o do
all
mai
ns d
istri
butio
n ne
twor
ks, d
ue to
th
e co
mbi
natio
n of
pre
dom
inan
tly
indu
ctiv
e w
iring
with
pre
dom
inan
tly
capa
citiv
e el
ectro
nic
load
s (e
.g.
due
to th
e ca
paci
tors
in th
eir E
MI
fi lte
rs o
f pow
er fa
ctor
cor
rect
ion
bank
s, s
ee C
.1.3
.4 o
f [1]
). N
oise
cu
rren
ts fl
owin
g in
them
will
cau
se
ampl
ifi ed
vol
tage
s at
thes
e re
sona
nt
frequ
enci
es, s
omet
imes
as
muc
h as
te
n tim
es h
ighe
r tha
n w
ould
nor
mal
ly
be e
xpec
ted.
[15]
incl
udes
som
e ex
ampl
es o
f ser
ious
pro
blem
s th
at
occu
rred
bec
ause
noi
se w
as a
mpl
ifi ed
in
mai
ns fi
lters
or m
ains
dis
tribu
tion
netw
orks
.
It ca
n co
me
as a
big
sur
pris
e to
fi n
d th
at a
mai
ns fi
lter i
s gi
ving
ga
in in
stea
d of
atte
nuat
ion,
ofte
n in
con
tradi
ctio
n to
the
supp
liers
at
tenu
atio
n ve
rsus
freq
uenc
y cu
rves
! Th
is is
due
to th
e fa
ct th
at m
ains
fi l
ters
are
not
test
ed in
situ
atio
ns th
at
corr
espo
nd to
real
-life
ope
ratio
n.
How
ever
, in
this
exa
mpl
e, if
the
mai
ns fi
lter w
as re
sona
ting
and
givi
ng
ampl
ifi ca
tion,
it w
as b
elow
150
kHz.
The
solu
tion
was
ver
y si
mpl
e –
the
mac
hini
ng c
entre
man
ufac
ture
r re
plac
ed th
e or
igin
al m
ains
fi lte
r on
thei
r PD
S w
ith o
ne th
at p
rovi
ded
relia
ble
atte
nuat
ion
dow
n to
bel
ow
10kH
z. T
his
fi lte
r was
muc
h th
e sa
me
size
as
the
orig
inal
, but
wei
ghed
a lo
t m
ore
and
was
mor
e co
stly.
It w
as a
lso
less
effi
cien
t, dr
oppe
d a
few
mor
e
Figu
re 5
: A
clos
er v
iew
of t
he
10-3
0kH
z no
ise,
abo
ut 1
5V
peak
-to-p
eak
Pha
se-n
eutra
l noi
se is
app
rox.
15V
p-p
at b
etw
een
10 a
nd 3
0 kH
z(P
hase
-ear
th is
sam
e, b
ut o
nly
4Vp-
p)
So
fi lte
ring
a V
SD
’s m
otor
out
put c
an
be a
n ex
celle
nt fi
nanc
ial i
nves
tmen
t!
For e
xam
ple,
the
maj
ority
of e
lect
rical
su
bmer
sibl
e pu
mps
(ES
Ps)
rate
d up
to
aro
und
900-
1100
kW s
ervi
ng th
e oi
l in
dust
ry o
ffsho
re, w
ould
not
func
tion
unle
ss o
utpu
t fi lt
ers
wer
e in
stal
led.
3.4
An
exam
ple
of th
e fi n
anci
al ri
sks
of in
adeq
uate
EM
C e
ngin
eerin
g[1
5] h
as m
any
exam
ples
of c
ostly
pr
oble
ms
caus
ed b
y E
MI f
rom
, or
to, P
DS
s, in
clud
ing
indu
stria
l one
s,
and
I mus
t say
that
ove
r the
last
20
yea
rs, a
lmos
t all
of m
y w
ork
as
in in
depe
nden
t EM
C c
onsu
ltant
in
solv
ing
EM
I pro
blem
s in
indu
stria
l si
tes
has
been
cau
sed
by tw
o el
ectro
nic
tech
nolo
gies
– v
aria
ble
spee
d m
otor
driv
es (i
.e. P
DS
s) a
nd
pers
onal
wire
less
com
mun
icat
ions
(e
.g. p
rivat
e m
obile
radi
o, W
alki
e-ta
lkie
s, c
ellp
hone
s). H
ere
and
in
3.5
are
just
two
exam
ples
of c
ostly
E
MI c
once
rnin
g P
DS
s, w
hich
do
not
appe
ar in
[15]
. [37
] is
anot
her c
ase
stud
y of
sol
ving
a h
igh-
pow
er V
SD
E
MI p
robl
em th
at h
ad b
een
very
co
stly
for t
he d
rive
user
.
This
fi rs
t exa
mpl
e al
so s
how
s th
at
actu
al c
ompl
ianc
e w
ith th
e te
st li
mits
an
d le
vels
in E
N/IE
C 6
1800
-3 d
oes
not a
utom
atic
ally
ens
ure
com
plia
nce
with
the
EM
C D
irect
ive
[2] [
7], o
r en
sure
low
fi na
ncia
l ris
ks.
It co
ncer
ns a
UK
fact
ory
that
had
a
new
(and
ver
y la
rge
and
cost
ly)
prog
ram
mab
le m
achi
ning
cen
tre
inst
alle
d. T
his
used
a 5
0kW
PD
S
(act
ually
a V
FD) t
hat c
ompl
ied
with
E
N/IE
C 6
1800
-3, s
o w
as a
ssum
ed
to c
ompl
y w
ith th
e E
MC
Dire
ctiv
e [2
] [7
]. B
ut w
hen
it w
as o
pera
ted
it pu
t ab
out 1
5V p
eak-
to-p
eak
at b
etw
een
10 a
nd 3
0kH
z on
the
fact
ory’
s m
ains
su
pply,
cau
sing
som
e pa
ckag
ing
mac
hine
s to
mal
func
tion
else
whe
re
on th
e si
te. F
igur
es 4
and
5 s
how
th
e m
ains
vol
tage
I m
easu
red
on th
e si
te w
hen
the
mac
hini
ng c
entre
was
ru
nnin
g. W
hen
it w
as n
ot ru
nnin
g, th
e m
ains
sup
ply
was
a n
ice
clea
n 50
Hz
sine
wav
e.
Figu
re 4
:O
ne p
eak
of th
e m
ains
cyc
le,
show
ing
the
10-3
0kH
z no
ise
Pea
k of
mai
ns w
avef
orm
, sho
win
g
nois
e ca
used
by
oper
atio
n of
new
m
achi
ning
cen
tre
1415
safe
ty s
tand
ards
. The
site
cou
ld n
ot
be o
pera
ted
until
the
prob
lem
was
fi x
ed, w
hich
took
sev
eral
mon
ths
with
th
e co
st o
f los
t pro
duct
ion
runn
ing
at
abou
t £10
0,00
0 pe
r wee
k.
Figu
re 6
sho
ws
som
e of
the
nois
es
crea
ted
by th
ese
pow
erfu
l driv
es,
befo
re th
eir m
ains
em
issi
ons
wer
e su
ppre
ssed
.
0.00
0
-200
.0
-400
.0
-600
.0
200.
0
400.
0
600.
0
V
40 30 20
V1 W
avef
orm
346.
38 V
rms,
13.
35%
TH
D
Red
, blu
e an
d bl
ack
are
the
thre
e ph
ases
,an
d th
e gr
een
trac
e is
the
eart
h/gr
ound
All
of th
em s
uffe
ring
over
100
V p-
p of
nois
e at
the
2kH
z ch
oppi
ng fr
eque
ncy
of th
e ne
arly
1M
W V
FD10 0
15
1015
2025
3035
4045
50
Figu
re 6
: Vo
ltage
noi
ses
on th
e si
te’s
3-p
hase
mai
ns s
uppl
y, d
ue to
one
PD
S
volts
and
ran
hotte
r. (In
cide
ntal
ly,
the
repl
acem
ent fi
lter
was
the
one
reco
mm
ende
d by
the
VFD
m
anuf
actu
rer,
so th
e fa
ult l
ay w
ith th
e m
achi
ning
cen
tre m
anuf
actu
rer,
not
the
VFD
man
ufac
ture
r.)
The
man
ufac
ture
r of t
he m
achi
ning
ce
ntre
had
sav
ed a
few
£ b
y us
ing
a ch
eape
r fi lt
er th
an th
e on
e re
com
men
ded,
but
this
cau
sed
sign
ifi ca
nt fi
nanc
ial l
osse
s fo
r the
ir cu
stom
er, a
nd th
ey a
lso
had
to s
pend
a
cons
ider
able
am
ount
them
selv
es
on fi
eld
serv
ice
visi
ts to
dea
l with
th
e cu
stom
er’s
com
plai
nts
over
se
vera
l mon
ths,
and
eve
ntua
lly fi
x th
e pr
oble
m w
hen
I sho
wed
them
wha
t it
was
. Ove
rall,
it w
ould
hav
e be
en
muc
h m
ore
cost
-effe
ctiv
e to
hav
e sh
ippe
d th
e pr
oduc
t with
the
bette
r fi l
ter.
Sin
ce th
e m
achi
ning
cen
tre it
self
sold
for o
ver £
1 m
illio
n, w
hy ta
ke
such
a ri
sk ju
st to
sav
e on
e or
two
hund
red
£ on
the
chea
per m
ains
fi l
ter?
Unf
ortu
nate
ly, th
at is
how
m
ost m
anuf
actu
ring
com
pani
es
are
man
aged
thes
e da
ys, w
ith
good
eng
inee
ring
prac
tices
mad
e su
bser
vien
t to
crud
e an
alys
es o
f BO
M
cost
[23]
, ofte
n re
sulti
ng in
sig
nifi c
ant
fi nan
cial
risk
s, a
s pr
oved
by
this
ex
ampl
e.
It is
inte
rest
ing
to n
ote
that
alth
ough
th
e m
achi
ning
cen
tre w
ith th
e or
igin
al fi
lter m
et th
e em
issi
ons
limits
w
hen
test
ed to
EN
/IEC
618
00-3
,
it di
d no
t act
ually
com
ply
with
the
EM
C D
irect
ive
[2] [
7] b
ecau
se it
ca
used
una
ccep
tabl
e in
terfe
renc
e to
ot
her e
quip
men
t whe
n in
stal
led
as
reco
mm
ende
d by
its
man
ufac
ture
r, an
d so
did
not
com
ply
with
the
Dire
ctiv
e’s
Ess
entia
l Req
uire
men
ts,
see
[3].
3.5.
A s
econ
d ex
ampl
e of
the
fi nan
cial
risk
s of
inad
equa
te
EMC
eng
inee
ring
This
exa
mpl
e co
ncer
ns h
eavy
in
dust
ry, w
ith a
com
pany
that
bui
lt,
owne
d an
d op
erat
ed in
stal
latio
ns th
at
used
PD
Ss
rate
d at
nea
rly 1
MW
. The
B
DM
s th
ey p
urch
ased
wer
e no
t fi tt
ed
with
mai
ns fi
lters
, and
sin
ce th
ey h
ad
neve
r suf
fere
d fro
m a
ny s
igni
fi can
t pr
oble
ms,
whi
ch w
ere
iden
tifi e
d as
bei
ng c
ause
d by
EM
I, in
thei
r in
stal
latio
ns, t
hey
felt
that
igno
ring
the
cost
s of
sup
pres
sing
the
emis
sion
s fro
m th
ese
very
pow
erfu
l mot
or d
rives
w
as ju
stifi
ed.
If th
ey e
ven
knew
that
this
was
not
go
od E
MC
eng
inee
ring
prac
tice,
they
ne
verth
eles
s ig
nore
d it
beca
use
it w
as
appa
rent
ly s
avin
g th
em m
oney
.
But
rece
ntly
(at t
he ti
me
of w
ritin
g),
one
of th
eir n
ew in
stal
latio
ns d
id s
uffe
r fro
m E
MI w
ith it
s co
ntro
l ele
ctro
nics
, w
ith p
oten
tially
leth
al s
afet
y ris
ks fo
r an
yone
nea
r to
the
mac
hine
ry b
eing
co
ntro
lled.
Als
o, th
e gr
ound
noi
se
volta
ges
exce
eded
thos
e al
low
ed b
y
1617
4. E
mis
sion
s
4.1.
The
bas
ic s
truc
ture
of a
B
DM
Figu
re 7
sho
ws
the
basi
c “b
lock
di
agra
m” o
f the
BD
M fo
r a V
FD fo
r an
AC
mot
or. I
t is
basi
cally
just
a m
ains
re
ctifi
er th
at p
rodu
ces
a D
C s
uppl
y (o
ften
calle
d a
“DC
-Lin
k”),
follo
wed
by
a p
ulse
-wid
th-m
odul
ated
(PW
M)
pow
er s
witc
hing
circ
uit (
ofte
n ca
lled
a ch
oppe
r, sw
itche
r or i
nver
ter)
. S
omet
imes
the
term
s ch
oppe
r, sw
itche
r or i
nver
ter a
re a
pplie
d to
the
who
le B
DM
incl
udin
g th
e re
ctifi
er. I
n a
low
-pow
er V
FD (<
10kW
), th
e ch
oppe
r m
ight
use
“Pow
erFE
T” d
evic
es, b
ut
alm
ost a
ll hi
gher
pow
er c
hopp
ers
use
IGB
Ts (I
nsul
ated
Gat
e B
ipol
ar
Tran
sist
ors)
inst
ead.
Any
DC
or A
C w
avef
orm
can
be
synt
hesi
sed
by c
hopp
ing
at a
hig
her
frequ
ency
(mus
t be
at le
ast t
wic
e th
e w
ante
d fre
quen
cy) b
y va
ryin
g its
mar
k:sp
ace
(i.e.
on:
off)
ratio
. C
hopp
ing
does
n’t w
aste
muc
h en
ergy
as
hea
t, w
hich
is w
hy P
WM
driv
es
are
muc
h sm
alle
r and
less
cos
tly, a
nd
mor
e ef
fi cie
nt, t
han
prev
ious
mot
or
spee
d co
ntro
l tec
hnol
ogie
s, a
nd w
hy it
is
so
popu
lar.
L1 L2 L3
M 3
Cho
pper
also
cal
led
switc
her
or in
verte
r
DC
Link
Rec
tifi
er6-
Pul
se ty
pesh
own
here
AC
Mot
orM
ains
Sup
ply
Figu
re 7
: B
lock
dia
gram
of a
VFD
for a
n A
C m
otor
It tu
rned
out
that
the
cost
of t
he
lost
pro
duct
ion
on th
is o
ne n
ew s
ite
was
man
y tim
es la
rger
than
the
com
pany
wou
ld h
ave
incu
rred
if it
had
al
way
s in
stal
led
PD
Ss
usin
g go
od
EM
C e
ngin
eerin
g pr
actic
es (w
hich
m
eans
usi
ng m
ains
fi lte
rs, s
ee la
ter)
. Th
is is
stil
l tru
e ev
en w
hen
usin
g a
disc
ount
ed c
ash-
fl ow
ana
lysi
s th
at
take
s th
e co
st o
f bor
row
ing
the
extra
m
oney
for t
he e
arlie
r, ap
pare
ntly
tro
uble
-free
inst
alla
tions
into
acc
ount
.
This
just
goe
s to
sho
w th
at w
e ca
n’t
beat
Mur
phy’
s La
w –
“If a
thin
g ca
n go
w
rong
, it w
ill”.
We
mig
ht th
ink
we
are
getti
ng a
way
with
poo
r eng
inee
ring
and
savi
ng m
oney
as
a re
sult,
but
(ju
st li
ke g
ambl
ing)
our
luck
can
not
hold
for e
ver.
In th
e en
d w
e w
ill b
e w
orse
off
than
if w
e ha
d al
way
s do
ne
good
eng
inee
ring.
For
mor
e on
why
M
urph
y’s
Law
is a
ctua
lly tr
ue (a
t lea
st
in p
art),
see
[27]
.
The
only
situ
atio
n w
here
this
“rul
e”
does
n’t a
pply,
is if
you
r com
pany
ha
s no
bra
nd im
age
and
is h
appy
to
sup
ply
peop
le w
ith ru
bbis
h an
d th
en “d
isap
pear
” (e.
g. b
y ch
angi
ng
nam
es) s
o as
not
to h
ave
to d
eal w
ith
the
resu
lting
hig
h w
arra
nty
cost
s.
Ther
e is
alw
ays
som
eone
will
ing
to
buy
from
an
unkn
own
man
ufac
ture
r, if
they
hav
e th
e lo
wes
t pric
e, s
o th
ere
is a
lway
s a
mar
ket f
or s
uch
man
ufac
ture
rs. I
’m s
ure
it w
ill c
ome
as n
o su
rpris
e th
at th
is G
uide
is n
ot
inte
nded
for u
se b
y su
ch c
ompa
nies
.
1819
The
shar
per t
he e
dges
of t
he P
WM
, th
e hi
gher
the
frequ
ency
rang
e of
th
e em
issi
ons.
Fig
ure
10 s
how
s an
exa
mpl
e of
the
wav
efor
m a
nd
frequ
ency
spe
ctru
m o
f a 1
6kH
z sq
uare
wav
e (i.
e. a
ver
y si
mpl
e, 1
:1
mar
k-sp
ace
ratio
PW
M) w
ith 2
μs ri
se
and
fall
times
. The
ana
lysi
s of
the
squa
rew
ave
in te
rms
of fr
eque
ncy
show
s th
at m
ost o
f its
ene
rgy
is a
t the
16
kHz
switc
hing
rate
, and
that
it a
lso
has
sign
ifi ca
nt e
nerg
y at
all
the
odd-
16kH
z sq
uare
-wav
e P
WM
with
2μs
rise
/fall
times
(whe
n m
easu
red
with
an
osci
llosc
ope)
2050
100
200
500
1,00
02,
000
kHz
dB0
-10
-20
-30
-40
-50
-60
Fundamental (16kHz)
3rd Harmonic of 16kHz
5th Harmonic of 16kHz
7th Harmonic
11th Harmonic9th Harmonic
etc...
The
sam
e w
avef
orm
whe
n m
easu
red
with
a s
pect
rum
ana
lyse
r
Figu
re 1
0:
Exam
ple
of fr
eque
ncy
cont
ent o
f a 1
6kH
z sq
uare
wav
e PW
M w
ith
2μs
rise
and
fall
times
A sq
uare
wav
e is
a s
peci
al c
ase
of
a ch
oppe
r out
put w
avef
orm
, and
ty
pica
l PW
M w
avef
orm
s ar
e ge
nera
lly
rect
angu
lar (
i.e. t
heir
mar
k:sp
ace
ratio
s ar
e us
ually
not
1:1
). Th
is
mea
ns th
at th
eir f
requ
ency
spe
ctra
al
so c
onta
in e
ven-
orde
r har
mon
ics
of th
eir c
hopp
ing
frequ
ency
(e.g
. 2nd
, 4th
, 6th, e
tc.).
It a
lso
mea
ns th
at th
e le
vels
of t
he v
ario
us h
arm
onic
s do
no
t sho
w th
e si
mpl
e gr
adua
l fal
l-of
f with
incr
easi
ng fr
eque
ncy
that
w
e se
e in
Fig
ure
10. S
ome
high
fre
quen
cy h
arm
onic
s m
ay h
ave
high
er
num
bere
d ha
rmon
ics,
for e
xam
ple
at:
48kH
z (3
rd h
arm
onic
)
80kH
z (5
th h
arm
onic
)
112k
Hz
(7th h
arm
onic
)
144k
Hz
(9th h
arm
onic
)
176k
Hz
(11th
har
mon
ic)
...et
c., a
ll th
e w
ay to
at l
east
1.
616M
Hz
(the
101st
har
mon
ic) a
nd
beyo
nd
Figu
re 8
is c
opie
d fro
m [2
8], a
nd
show
s a
sim
ple
exam
ple
of g
ener
atin
g a
sine
wav
e us
ing
PW
M. T
he id
ea
is th
at w
hen
aver
aged
ove
r a fe
w
switc
hing
cyc
les,
the
rapi
d ch
oppi
ng
of th
e w
avef
orm
bec
omes
a s
moo
th
AC
wav
efor
m. S
o w
hen
used
to d
rive
a m
otor
, the
hig
h in
duct
ance
in it
s w
indi
ngs
caus
es th
e m
otor
cur
rent
to
follo
w th
e av
erag
e va
lue
of th
e P
WM
vo
ltage
. In
the
exam
ple
of F
igur
e 8,
this
resu
lts in
a s
inew
ave
at th
e
frequ
ency
requ
ired
to d
rive
the
AC
m
otor
at t
he ro
tatio
nal s
peed
requ
ired.
Figu
re 9
sho
ws
an e
xam
ple
of a
PW
M
mot
or o
utpu
t mea
sure
d w
ith a
pow
er
qual
ity m
eter
, on
a 90
0kW
VFD
. B
ecau
se th
e m
easu
ring
inst
rum
ent
that
was
use
d ha
s a
band
wid
th o
f onl
y ab
out 5
kHz,
the
PW
M v
olta
ge s
igna
ls
in F
igur
e 9
are
“ave
rage
d” to
som
e ex
tent
and
do
not a
ppea
r as
squa
re o
r sh
arp-
edge
d as
they
real
ly a
re.
1.5
1.0
0.5 0
-0.5
-1.0
-1.5
05
1015
(ms)
20
VB
B(T), V(v)
Figu
re 8
:Ex
ampl
e of
PW
M u
sed
to
crea
te a
sin
ewav
e
Figu
re 9
:Exa
mpl
e of
PW
M o
utpu
t of a
900
kW V
FD, m
easu
red
with
a 5
kHz
band
wid
th
2021
The
curr
ent w
avef
orm
of a
linea
r loa
d, s
uppl
ied
from
asi
new
ave
volta
ge
The
non-
linea
r cur
rent
wav
efor
m ty
pica
lof
a s
ingl
e-ph
ase
phas
e-an
gle-
cont
rolle
dtr
iac,
sup
plie
d fr
om a
sin
ewav
e vo
ltage
5015
025
035
045
0
50 H
z m
ains
sup
ply
A
Hz
... a
nd it
s fr
eque
ncy
spec
trum
5015
025
035
045
0
50 H
z m
ains
sup
ply
A
Hz
... a
nd a
n ex
ampl
e sp
ectr
um
etc
Figu
re 1
2:H
arm
onic
cur
rent
s in
a s
ingl
e-ph
ase
phas
e-an
gle-
cont
rolle
d tr
iac
brid
ge
In th
ree-
phas
e (o
ften
calle
d 6-
puls
e)
rect
ifi er
s an
d ph
ase-
angl
e co
ntro
lled
triac
s su
pplie
d fro
m a
goo
d qu
ality
si
new
ave
volta
ge, t
he “t
riple
n”
harm
onic
s (3
rd, 9
th, 1
5th,
etc
.) ca
ncel
ou
t alm
ost e
ntire
ly in
the
circ
uit.
H
owev
er, i
f the
re is
any
imba
lanc
e in
the
supp
ly v
olta
ges,
trip
lens
ar
e pr
oduc
ed.
Sim
ilarly
, for
mul
ti-pu
lse
syst
ems
(e.g
. 12
puls
e) a
ny
imba
lanc
es in
the
para
llele
d 6
puls
e re
ctifi
ers,
pha
se s
hift
trans
form
er
seco
ndar
y w
indi
ngs
resu
lts in
trip
lens
an
d ot
her u
nwan
ted
nois
e em
issi
ons
bein
g pr
oduc
ed.
4.2.
The
unw
ante
d no
ise
sour
ces
in a
BD
MTh
e ab
ove
disc
ussi
on h
as s
how
n th
at, i
n a
BD
M, r
ectifi
ers
gen
erat
e cu
rren
ts a
t the
mai
ns fr
eque
ncy
and
its h
arm
onic
s, a
nd c
hopp
ers
gene
rate
vo
ltage
s at
kH
z fre
quen
cies
plu
s th
eir
harm
onic
s –
even
up
to te
ns o
f MH
z.
ampl
itude
s th
an lo
wer
freq
uenc
y on
es.
A D
C m
otor
driv
e ca
n us
e P
WM
just
lik
e a
VFD
, it o
nly
requ
ires
the
PW
M
wav
efor
m to
be
such
that
the
mot
or
curr
ent a
vera
ges
to a
DC
cur
rent
in
stea
d of
to a
n A
C o
ne.
But
som
e ty
pes
of p
ower
ful A
C a
nd
DC
mot
or d
rives
use
thyr
isto
r or t
riac
devi
ces
switc
hed
on a
nd o
ff at
the
frequ
ency
of t
he m
ains
pow
er, i
nste
ad
of p
lain
rect
ifi er
s. T
hey
don’
t nee
d to
us
e a
DC
-Lin
k or
a c
hopp
er. P
hase
-an
gle-
cont
rolle
d tri
acs
are
used
to
gene
rate
a v
aria
ble
DC
vol
tage
, an
d ap
prop
riate
on/
off s
witc
hing
of
thyr
isto
rs c
an g
ener
ate
AC
at
frequ
enci
es a
t up
to 5
0% o
f the
mai
ns
supp
ly fr
eque
ncy
(thes
e ar
e ca
lled
cycl
ocon
verte
rs).
Rec
tifi e
rs, w
heth
er p
lain
or p
hase
-an
gle
cont
rolle
d, o
r cyc
loco
nver
ters
, ge
nera
te h
arm
onic
s of
thei
r sw
itchi
ng
frequ
ency
– w
hich
is th
e m
ains
– a
nd
so th
ey g
ener
ate
wha
t we
call
“mai
ns
harm
onic
s” to
dis
tingu
ish
them
from
ot
her s
witc
hing
har
mon
ics.
Figu
re 1
1 sh
ows
the
fi rst
few
ha
rmon
ics
of th
e cu
rren
t in
a si
ngle
-ph
ase
brid
ge re
ctifi
er, w
hils
t Fig
ure
12 s
how
s th
ose
for a
pha
se-a
ngle
-co
ntro
lled
sing
le-p
hase
rect
ifi er
(whi
ch
coul
d be
a V
SD
for a
DC
mot
or).
The
curr
ent w
avef
orm
of a
linea
r loa
d, s
uppl
ied
from
asi
new
ave
volta
ge
The
non-
linea
r cur
rent
wav
efor
m ty
pica
lof
a s
ingl
e-ph
ase
rect
ifier
-cap
acito
r inp
utA
C-D
C p
ower
con
vert
er,
supp
lied
from
a s
inew
ave
volta
ge
5015
025
035
045
0
50 H
z m
ains
sup
ply
A
Hz
... a
nd it
s fr
eque
ncy
spec
trum
5015
025
035
045
0
50 H
z m
ains
sup
ply
A
Hz
... a
nd a
n ex
ampl
e sp
ectr
um
etc
Figu
re 1
1: H
arm
onic
cur
rent
s in
a s
ingl
e-ph
ase
brid
ge re
ctifi
er
2223
VFD
, the
mot
or d
raw
s its
ele
ctric
al
pow
er a
t the
AC
freq
uenc
y th
at
is s
ynth
esis
ed b
y th
e P
WM
of i
ts
chop
per,
and
as a
resu
lt th
e cu
rren
t in
the
DC
-Lin
k an
d th
e m
ains
cur
rent
de
man
d bo
th fo
llow
this
freq
uenc
y.
For e
xam
ple,
if a
VFD
is s
et to
39H
z,
then
whe
n dr
ivin
g its
load
ed m
otor
it
draw
s cu
rren
t fro
m th
e m
ains
at
39H
z. A
nd b
ecau
se m
ains
rect
ifi er
s ar
e sw
itchi
ng c
ircui
ts a
nd n
ot li
near
on
es, t
hey
gene
rate
har
mon
ics
of th
is
frequ
ency
too.
Thes
e lo
w-fr
eque
ncy
non-
fund
amen
tal-r
elat
ed (5
0Hz
in E
urop
e)
mai
ns c
urre
nts
are
calle
d m
ains
“in
terh
arm
onic
s”, a
nd ju
st li
ke m
ains
ha
rmon
ics
they
circ
ulat
e w
idel
y in
the
mai
ns d
istri
butio
n ne
twor
k,
caus
ing
exce
ss h
eatin
g an
d di
stor
ting
the
volta
ge w
avef
orm
. DC
driv
es
can
also
gen
erat
e in
terh
arm
onic
s to
som
e de
gree
, whe
n th
e lo
ad o
n th
eir m
otor
s, o
r the
ir m
otor
spe
ed,
fl uct
uate
s re
petit
ivel
y an
d ra
pidl
y.
Just
as
for m
ains
har
mon
ics,
[1] a
nd
othe
r sta
ndar
ds s
peci
fy te
sts
and
limits
for i
nter
harm
onic
em
issi
ons.
Inte
rhar
mon
ic e
mis
sion
s ar
e m
ade
mor
e co
mpl
ex b
y in
term
odul
atio
n w
ithin
the
mai
ns re
ctifi
er. T
he m
ains
vo
ltage
freq
uenc
y an
d its
har
mon
ics
(dis
torte
d w
avef
orm
) int
erm
odul
ates
w
ith th
e A
C m
otor
driv
e fre
quen
cy
and
its h
arm
onic
s, to
cre
ate
a hu
ge
num
ber o
f “In
term
odul
atio
n P
rodu
cts”
. Fi
gure
13
show
s a
mea
sure
men
t tha
t
was
mad
e on
the
curr
ent s
pect
rum
of
a 70
0kW
VFD
, and
sho
ws
sign
ifi ca
nt
curr
ent l
evel
s at
, for
inst
ance
24A
at
103
.75H
z, w
hich
is s
ix ti
mes
the
mai
ns fr
eque
ncy
(nea
r to
50H
z) m
inus
fi v
e tim
es th
e m
otor
freq
uenc
y of
39
.4H
z.
The
gene
rato
rs u
sed
to p
rovi
de m
ains
po
wer
onl
y ge
nera
te a
t 50H
z (o
r 60
Hz)
, so
mai
ns h
arm
onic
cur
rent
s ar
e a
nuis
ance
. The
y ci
rcul
ate
wid
ely
in th
e m
ains
dis
tribu
tion
netw
ork
caus
ing
exce
ss h
eatin
g of
the
cabl
es,
indu
ctio
n m
otor
s, tr
ansf
orm
ers,
fuse
s an
d ci
rcui
t-bre
aker
s, a
nd a
s th
ey
fl ow
in th
e im
peda
nces
of t
he s
uppl
y ne
twor
k th
ey c
ause
vol
tage
dro
ps th
at
dist
ort t
he m
ains
wav
efor
m s
o th
at it
is
not
a c
lean
sin
ewav
e an
ymor
e. W
e sa
y th
at it
is h
arm
onic
ally
dis
torte
d,
and
whe
n vo
ltage
dis
torti
on le
vels
ris
e to
o hi
gh, m
any
kind
s of
ele
ctro
nic
equi
pmen
t can
mal
func
tion.
For
mor
e on
the
prob
lem
s of
mai
ns h
arm
onic
s,
see
[29]
and
[30]
, and
als
o th
e R
EO
G
uide
s on
EN
610
00-3
-2 a
nd E
N
6100
0-4-
13, f
rom
the
list a
t [4]
.
Sin
ce m
ains
har
mon
ics
do n
ot
cont
ribut
e to
del
iver
ed p
ower
(the
y ar
e ca
lled
“wat
tless
pow
er”,
wor
seni
ng
the
True
Pow
er F
acto
r – c
ombi
natio
n of
the
disp
lace
men
t pow
er fa
ctor
and
th
e di
stor
tion
fact
or o
f har
mon
ics)
, an
d si
nce
they
cau
se m
any
prob
lem
s,
we
cons
ider
them
to b
e an
unw
ante
d no
ise
emis
sion
. EN
/IEC
618
00-3
[1]
defi n
es te
sts
and
sets
lim
its fo
r the
em
issi
ons
of m
ains
har
mon
ics
from
a
PD
S, a
s do
EN
/IEC
610
00-3
-2 (f
or
ratin
gs u
p to
15A
/pha
se) a
nd E
N/IE
C
6100
0-3-
12 (f
or ra
tings
up
to 7
5A/
phas
e).
Mot
ors
have
too
muc
h m
echa
nica
l in
ertia
and
ele
ctric
al in
duct
ance
to
resp
ond
to k
Hz
chop
ping
freq
uenc
ies,
ne
ver m
ind
thei
r har
mon
ics
– bu
t the
y ca
n su
ffer i
ncre
ased
dow
ntim
e du
e to
th
eir i
nsul
atio
n fa
ilure
, mot
or b
earin
g pr
oble
ms
and
cabl
es b
eing
deg
rade
d by
the
high
freq
uenc
ies.
In
addi
tion,
in
duct
ion
mot
ors
with
dee
p ba
r or
doub
le c
age
desi
gn c
an o
verh
eat
sign
ifi ca
nt o
n he
avily
dis
torte
d su
pplie
s. O
n ex
plos
ion
proo
f (E
Exd
) m
otor
s w
ith th
ese
type
s of
roto
r de
sign
, the
fl am
epro
of s
eals
on
the
shaf
t, w
hich
are
des
igne
d to
con
tain
an
y in
tern
al e
xplo
sion
, can
bec
ome
degr
aded
, pos
sibl
y al
low
ing
any
inte
rnal
exp
losi
on to
be
trans
mitt
ed
outs
ide
the
mot
or c
arca
ss w
ith
poss
ibly
dis
astro
us c
onse
quen
ces.
If th
e ch
oppi
ng fr
eque
ncie
s an
d/or
th
eir h
arm
onic
s co
uple
with
oth
er
equi
pmen
t (vi
a co
nduc
tion,
indu
ctio
n or
radi
atio
n) th
ey c
an in
terfe
re
with
its
oper
atio
n. S
o it
is g
ood
engi
neer
ing
prac
tice
to tr
eat t
he
chop
ping
freq
uenc
y an
d its
har
mon
ics
as p
oten
tial s
ourc
e of
noi
se o
r de
grad
atio
n th
at s
houl
d be
con
trolle
d.
[1] s
peci
fi es
test
s an
d se
ts li
mits
for
the
amou
nt o
f con
duct
ed a
nd ra
diat
ed
emis
sion
s, in
com
mon
with
man
y ot
her E
MC
sta
ndar
ds, s
uch
as th
e ge
neric
em
issi
ons
stan
dard
s E
N/IE
C
6100
0-6-
3 an
d E
N/IE
C 6
1000
-6-4
.
So,
we
have
to li
mit
our P
DS
’s
emis
sion
s of
mai
ns h
arm
onic
s,
and
chop
per f
requ
enci
es a
nd th
eir
harm
onic
s. B
ut th
is is
not
all.
In a
2425
and
volta
ge fl
uctu
atio
ns d
ue to
load
cu
rren
t cha
nges
; so
this
Gui
de w
ill
desc
ribe
the
tech
niqu
es th
at a
re u
sed
to c
ontro
l noi
se e
mis
sion
s fo
r VFD
s th
at u
se P
WM
. The
sam
e te
chni
ques
al
so w
ork
for t
hyris
tor a
nd tr
iac
driv
es, w
hich
will
pro
babl
y ne
ed m
ore
atte
ntio
n pa
ying
to s
uppr
essi
ng n
oise
em
issi
ons
in th
e lo
wer
freq
uenc
y ra
nge
(i.e.
bel
ow 1
50kH
z).
Varia
ble
spee
d m
otor
driv
es a
re a
lso
used
to d
rive
vario
us k
inds
of m
otor
s in
ser
vo s
yste
ms,
and
to d
rive
step
per
mot
ors.
The
se u
se th
e sa
me
DC
or
AC
PW
M m
otor
driv
e te
chno
logi
es
desc
ribed
abo
ve, s
o th
eir E
MC
sho
uld
be tr
eate
d th
e sa
me
way
.
Figu
re 1
4 sh
ows
how
the
nois
e cu
rren
ts fl
ow in
the
BD
M e
xam
ple
prev
ious
ly u
sed
in F
igur
e 7.
L1 L2 L3
Cho
pper
also
cal
led
switc
her
or in
verte
r
DC
Link
Rec
tifi
er6-
Pul
se ty
pesh
own
here
AC
Mot
orM
ains
Sup
ply
M 3 M
ains
har
mon
ics
and
DM
nois
e in
the
pow
er s
uppl
y
CM
noi
se d
ueto
the
rect
ifier
CM
noi
se d
ueto
the
chop
per
CM
noi
se fr
om re
ctifi
er a
nd c
hopp
erth
at a
lso
flow
s th
roug
h th
e D
C L
ink
PW
M o
utpu
t (ve
ryno
isy)
to th
e m
otor
This
sym
bol i
ndic
ates
inte
ntio
nal a
nd/o
r stra
y ca
paci
tanc
es to
thes
ite’s
ear
th/g
roun
d s
truct
ure
from
inte
rnal
com
pone
nts,
hea
tsin
ks, w
indi
ngs
etc.
(whe
ther
ext
erna
l cas
es/fr
ames
are
ear
thed
/gro
unde
d fo
r saf
ety
reas
ons
or n
ot)
To u
nder
stan
d Fi
gure
14,
we
have
to
unde
rsta
nd th
at th
ere
are
two
kind
s of
noi
se c
urre
nts
– di
ffere
ntia
l-mod
e (D
M) a
nd c
omm
on-m
ode
(CM
). A
ll cu
rren
ts fl
ow in
loop
s, a
nd D
M n
oise
cu
rren
ts fl
ow in
loop
s w
ithin
a s
ingl
e ca
ble
(or c
able
bun
dle)
. In
the
case
of
a th
ree-
phas
e de
lta c
onne
cted
V
FD li
ke th
at s
how
n in
Fig
ure
14, D
M
curr
ents
fl ow
out
and
bac
k al
ong
the
thre
e m
ains
pha
se c
ondu
ctor
s, a
nd
they
als
o fl o
w o
ut a
nd b
ack
alon
g th
e th
ree
mot
or p
hase
con
duct
ors.
How
ever
, CM
noi
se fl
ows
out a
long
all
of th
e co
nduc
tors
in a
cab
le o
r cab
le
bund
le a
t the
sam
e tim
e, a
nd re
turn
s vi
a a
diffe
rent
pat
h to
com
plet
e its
Figu
re 1
4:H
ow th
e no
ise
curr
ents
fl ow
in a
BD
M
The
rem
aind
er o
f thi
s G
uide
will
fo
cus
on V
FDs
and
VS
Ds
that
use
P
WM
, bec
ause
thes
e ar
e th
e w
orst
fo
r cre
atin
g hi
gh-fr
eque
ncy
nois
e em
issi
ons.
Thi
s is
bec
ause
thei
r ch
oppe
rs u
se v
ery
fast
-sw
itchi
ng
Pow
erFE
TS o
r IG
BTs
, whi
ch a
re
oper
ated
at k
Hz
switc
hing
rate
s –
as
low
as
1kH
z fo
r MW
pow
er ra
tings
; as
hig
h as
50k
Hz
for r
atin
gs a
roun
d 1k
W. W
e ca
n ex
pect
to h
ave
to
cont
rol n
oise
at f
requ
enci
es o
f up
to
1,00
0 tim
es th
e sw
itchi
ng ra
te (e
.g.
1MH
z fo
r a 1
kHz
chop
per,
50M
Hz
for
50kH
z).
Thyr
isto
rs a
nd tr
iacs
sw
itch
muc
h m
ore
slow
ly th
an P
ower
FETS
and
IG
BTs
, and
thei
r sw
itchi
ng ra
te is
no
high
er th
an th
e m
ains
freq
uenc
y. A
s a
resu
lt th
ey p
rodu
ce s
igni
fi can
tly
low
er le
vels
of h
igh-
frequ
ency
noi
se
emis
sion
s th
an a
PW
M d
rive
of th
e sa
me
pow
er ra
ting.
How
ever
, sin
ce
they
are
ofte
n us
ed a
t ver
y hi
gh
pow
ers,
thei
r hig
h-fre
quen
cy n
oise
em
issi
ons
can
be s
igni
fi can
t and
sh
ould
not
be
igno
red.
All
type
s of
VS
Ds
crea
te lo
w
frequ
ency
em
issi
ons
at h
arm
onic
s of
the
mai
ns s
uppl
y, in
terh
arm
onic
s,
From
Fig
ure
13 o
f: “P
ower
Sys
tem
Har
mon
ics,
Par
t 4: I
nter
harm
onic
s”R
. Yac
amin
i, IE
E P
ower
Jou
rnal
, Aug
ust 1
966
The
mot
or d
rive
frequ
ency
is 3
9.4H
z
Figu
re 1
3:Ex
ampl
e of
inte
rmod
ulat
ion
incr
easi
ng th
e in
terh
arm
onic
leve
ls in
a V
FD
2627
13) t
he ra
tios
of c
urre
nts
betw
een
the
loop
s is
freq
uenc
y-de
pend
ent.
Sim
ply
put,
we
shou
ld e
xpec
t the
CM
noi
se
from
a P
DS
to fl
ow a
ll ov
er th
e ea
rth/
grou
nd s
truct
ure
of a
site
or a
ves
sel.
L1 L2 L3
Cho
pper
also
cal
led
switc
her
or in
verte
r
DC
Link
Rec
tifi
er6-
Pul
se ty
pesh
own
here
AC
Mot
or
M 3
Filte
r mus
t be
RF-
bond
ed to
the
chop
per’s
met
alen
clos
ure
Rec
tifie
r and
cho
pper
met
alen
clos
ures
mus
t be
RF-
bond
ed
Mai
nsIn
duct
orha
rmon
icsu
ppre
ssio
n
Mai
ns F
ilter
very
clo
seto
rect
ifier
nois
e su
ppre
ssio
nkH
z - M
Hz
Out
put
Indu
ctor
and/
or F
ilter
ver
ycl
ose
to c
hopp
erno
ise
supp
ress
ion
kHz
- MH
z
Now
muc
h re
duce
d ha
rmon
ics,
DM
and
CM
noi
ses
flow
in th
e lo
ng m
ains
cab
le
Mos
t CM
noi
ses
now
flow
in m
uch
smal
ler l
oops
with
in th
e fil
ter/d
rive/
filte
r ass
embl
y
Now
muc
h re
duce
d D
M
and
CM
noi
ses
flow
in th
e lo
ng m
ains
cab
le
DC
noi
se in
the
mai
ns s
uppl
yP
WM
out
put
(ver
y no
isy)
Filte
r mus
tbe
RF-
bond
edto
the
rect
ifier
’s
met
al e
nclo
sure
Figu
re 1
5: U
sing
indu
ctor
s an
d fi l
ters
to s
uppr
ess
nois
e em
issi
ons
4.3.
Sup
pres
sing
the
nois
e so
urce
sFi
gure
15
show
s th
e us
e of
fi lte
rs a
t th
e B
DM
’s re
ctifi
er’s
inpu
t, an
d at
its
chop
per’s
out
put,
to s
uppr
ess
the
DM
an
d C
M n
oise
em
issi
ons.
The
best
way
to u
nder
stan
d ho
w a
fi l
ter s
uppr
esse
s D
M a
nd C
M n
oise
em
issi
ons,
is to
rega
rd it
as
a m
eans
of
pro
vidi
ng a
retu
rn p
ath
for t
he n
oise
cu
rren
t loo
ps th
at h
as a
muc
h lo
wer
im
peda
nce
than
the
othe
r loo
ps. T
he
nois
e cu
rren
t will
then
aut
omat
ical
ly
split
so
that
mos
t of i
t fl o
ws
in th
e pa
th
prov
ided
by
the
fi lte
r. Fi
lters
gen
eral
ly
use
capa
cito
rs to
pro
vide
thes
e lo
w-
impe
danc
e lo
ops.
Mos
t fi lt
ers
also
add
indu
ctor
s an
d ch
okes
to in
crea
se th
e im
peda
nce
of th
e m
ains
or m
otor
cab
les
on “t
he
othe
r sid
e” a
fter t
he p
rovi
sion
of t
he
low
-impe
danc
e re
turn
pat
h, to
hel
p en
cour
age
mos
t of t
he n
oise
cur
rent
s to
fl ow
in th
e ne
w p
ath
prov
ided
by
the
fi lte
r and
not
out
into
the
inst
alla
tion’
s ca
bles
whe
re it
mig
ht
caus
e in
terfe
renc
e.
Figu
re 1
5 sh
ows
the
mai
ns h
arm
onic
em
issi
ons
from
the
rect
ifi er
bei
ng
supp
ress
ed b
y a
thre
e-ph
ase
indu
ctor
, a
com
mon
tech
niqu
e of
ten
calle
d a
line
reac
tor (
or ju
st re
acto
r). O
ther
m
etho
ds a
re d
iscu
ssed
late
r.
loop
. Any
pat
h w
ill d
o, b
ut th
e on
e th
at
alw
ays
exis
ts is
via
the
earth
/gro
und
stru
ctur
e of
the
site
or v
esse
l the
P
SD
is in
stal
led
in. E
ven
whe
re n
o co
nduc
tive
path
exi
sts,
hig
h-fre
quen
cy
curr
ents
can
eas
ily fl
ow th
roug
h th
e ai
r or i
nsul
ator
s, v
ia s
tray
mut
ual
indu
ctan
ces
and
stra
y ca
paci
tanc
es.
Figu
re 1
4 in
dica
tes
som
e of
the
stra
y ca
paci
tanc
es th
at e
xist
in a
typi
cal
PD
S, w
hich
can
car
ry C
M c
urre
nts.
CM
cur
rent
s ar
e ca
used
by
imba
lanc
es b
etw
een
stra
y ca
paci
tanc
es a
nd s
tray
indu
ctan
ces,
fo
r exa
mpl
e, th
e st
ray
capa
cita
nce
of P
hase
1 to
ear
th/g
roun
d, v
ersu
s th
at o
f Pha
se 2
. The
se im
bala
nces
ar
e sm
all,
so C
M n
oise
cur
rent
s ar
e sm
all w
hen
com
pare
d w
ith th
e D
M
nois
e cu
rren
ts, b
ut s
ince
CM
cur
rent
s tra
vel i
n ve
ry la
rge
loop
s, w
hich
can
en
com
pass
a w
hole
site
or v
esse
l, th
ey h
ave
the
pote
ntia
l to
caus
e as
m
uch
(or m
ore)
inte
rfere
nce
as D
M
curr
ents
.
Figu
re 1
4 sh
ows
(as
a do
uble
-he
aded
arr
ow) t
he D
M n
oise
cu
rren
ts a
ssoc
iate
d w
ith th
e re
ctifi
er
– co
nsis
ting
of m
ains
har
mon
ics
and
inte
rhar
mon
ics
plus
hig
h-fre
quen
cy
switc
hing
noi
ses
from
the
rect
ifi er
s th
emse
lves
– fl
owin
g in
the
thre
e-ph
ase
mai
ns c
able
’s c
ondu
ctor
s.
It al
so s
how
s (a
lso
as a
dou
ble-
head
ed a
rrow
) the
DM
noi
se c
urre
nts
asso
ciat
ed w
ith th
e ch
oppe
r –
cons
istin
g of
the
set m
otor
freq
uenc
y an
d its
har
mon
ics,
plu
s th
e ch
oppe
r fre
quen
cy a
nd it
s ha
rmon
ics
– fl o
win
g in
the
thre
e-ph
ase
mot
or c
able
’s
cond
ucto
rs.
Figu
re 1
4 sh
ows
– as
red
ellip
ses
– th
e C
M n
oise
cur
rent
loop
as
soci
ated
with
the
rect
ifi er
and
mai
ns
supp
ly, a
nd th
e lo
op a
ssoc
iate
d w
ith
the
chop
per a
nd th
e m
otor
. It a
lso
show
s a
larg
er e
llips
e in
dica
ting
that
re
ctifi
er C
M n
oise
als
o fl o
ws
in a
loop
th
at c
ompr
ises
the
mot
or, c
hopp
er
and
DC
-Lin
k; a
nd th
at c
hopp
er n
oise
al
so fl
ows
in a
loop
that
com
pris
es th
e m
ains
sup
ply,
rect
ifi er
and
DC
-Lin
k.
I’m s
ure
the
read
er w
ill a
ppre
ciat
e th
at
Figu
re 1
4 is
a g
ross
sim
plifi
catio
n fo
r th
e pu
rpos
e of
illu
stra
tion,
and
that
its
sim
plifi
ed a
naly
sis
can
equa
lly w
ell b
e ap
plie
d to
VFD
s us
ing
sing
le-p
hase
, or
six
(or m
ore)
pha
se re
ctifi
ers.
Cur
rent
s fl o
w a
ccor
ding
to th
e im
peda
nce
that
they
exp
erie
nce
arou
nd th
eir e
ntire
loop
, and
whe
re
ther
e is
mor
e th
an o
ne a
ltern
ativ
e pa
th th
ey w
ill ta
ke a
ll of
them
, div
idin
g be
twee
n th
em in
a ra
tio th
at d
epen
ds
upon
the
impe
danc
es o
f eac
h, a
nd th
e fre
quen
cy c
once
rned
.
Stra
y ca
paci
tanc
e en
sure
s th
at th
ere
are
alw
ays
man
y al
tern
ativ
e lo
ops
for C
M c
urre
nts
to fl
ow in
, and
sin
ce
ther
e ar
e ve
ry m
any
nois
e fre
quen
cies
as
soci
ated
with
rect
ifi er
s an
d ch
oppe
rs (s
ee F
igur
es 1
0, 1
1, 1
2 an
d
2829
Figu
re 1
6 sh
ows
an e
xam
ple
of a
50
kW V
FD a
ssem
bled
in a
n in
dust
rial
cabi
net w
ith it
s m
ains
fi lte
r. N
ote
how
clo
se th
e m
ains
fi lte
r is
to th
e V
FD’s
rect
ifi er
, and
als
o ho
w b
oth
the
cond
uctiv
ely-
plat
ed m
etal
bod
ies
of th
e fi l
ter,
rect
ifi er
and
cho
pper
un
its a
re a
ll m
ulti-
poin
t bon
ded
to
the
cabi
net’s
con
duct
ivel
y-pl
ated
ba
ckpl
ate,
to p
rovi
de g
ood
RF-
bond
ing
up to
sev
eral
10s
of M
Hz.
Figu
re 1
5 sh
ows
how
this
app
roac
h re
duce
s P
DS
em
issi
ons,
by
show
ing
that
the
doub
le-h
eade
d ar
row
s of
th
e D
M n
oise
cur
rent
s, a
nd th
e re
d el
lipse
s of
the
CM
noi
se c
urre
nts,
are
al
l now
con
tain
ed w
ithin
the
asse
mbl
y co
mpr
isin
g th
e m
ains
fi lte
r, V
FD a
nd
outp
ut fi
lter.
They
are
not
sho
win
g as
fl o
win
g in
eith
er th
e m
ains
sup
ply
or
mot
or c
able
s.
See
4.4
.4 fo
r usi
ng a
n is
olat
ing
trans
form
er to
impr
ove
the
CM
pe
rform
ance
of m
ains
fi lte
rs, a
nd –
w
here
CM
noi
se is
the
only
sig
nifi c
ant
prob
lem
– p
ossi
bly
repl
acin
g th
e m
ains
fi lte
r ent
irely.
Figu
re 1
6:
Exam
ple
of a
50k
W d
rive
with
fi lte
red
mai
ns a
nd s
cree
ned
mot
or c
able
Mai
ns F
ilter
Mai
ns Is
olat
or
Filte
r, in
duct
or, r
ectifi
er a
nd c
hopp
er a
ll ha
ve m
etal
en
clos
ures
, are
all
clos
e to
geth
er, a
nd a
re a
ll m
ulti-
poin
t RF-
bond
ed to
one
con
duct
ivel
y-pl
ated
met
al b
ack-
plat
e
Mai
ns
Indu
ctor
s
50kW
VS
D C
hopp
er
Scr
eene
d m
otor
cab
le’s
scr
een
term
inat
ion
at c
hopp
er
50kW
VS
D R
ectifi
er
Not
e th
at F
igur
e 15
sho
ws
line
reac
tor
fi tte
d to
the
supp
ly s
ide
of th
e m
ains
fi l
ter,
not t
o its
BD
M s
ide,
bec
ause
th
is h
elps
pre
vent
reso
nanc
es in
the
mai
ns p
ower
dis
tribu
tion
netw
ork.
C
onne
ctin
g ca
paci
tors
dire
ctly
to
a su
pply
net
wor
k, w
ithou
t ser
ies
reac
tors
bet
wee
n th
em a
nd th
e su
pply,
has
bee
n se
en to
cau
se
reso
nanc
es th
at c
ause
d co
stly
da
mag
e to
equ
ipm
ent,
with
eve
n hi
gher
cos
ts d
ue to
its
dow
ntim
e.
Pro
vidi
ng a
low
-impe
danc
e pa
th fo
r D
M n
oise
cur
rent
s is
eas
y –
sim
ply
conn
ect c
apac
itors
bet
wee
n th
e ph
ase
cond
ucto
rs in
eac
h ca
ble.
Th
ese
will
tend
to “s
hort
out”
the
DM
cu
rren
ts, s
o th
ey d
on’t
get o
ut in
to th
e su
pply
or m
otor
cab
le, b
ut o
f cou
rse
no c
apac
itor i
s pe
rfect
so
the
nois
e cu
rren
t red
irect
ion
is n
ot p
erfe
ct e
ither
an
d so
me
DM
noi
se c
urre
nt w
ill s
till
fl ow
in th
e lo
ng c
able
s.
Red
irect
ing
the
CM
cur
rent
s al
so
uses
cap
acito
rs, b
ut th
ey h
ave
to
be c
onne
cted
to th
e ea
rth/g
roun
d st
ruct
ure,
so
to b
e ef
fect
ive
the
impe
danc
e in
the
earth
/gro
und
stru
ctur
e be
twee
n th
e fi l
ter a
nd th
e re
ctifi
er o
r cho
pper
mus
t be
very
sm
all
inde
ed. T
his
esse
ntia
lly m
eans
:
Loca
te th
e in
duct
ors
and/
or
fi lte
rs p
hysi
cally
as
clos
e as
pr
actic
able
to th
e un
it w
hose
no
ise
it is
to s
uppr
ess
(i.e.
the
rect
ifi er
or t
he c
hopp
er)
RF-
bond
the
met
al b
odie
s of
the
indu
ctor
s or
fi lte
rs to
the
met
al
body
of t
he u
nit w
hose
noi
se it
is
to s
uppr
ess.
(Eve
n th
ough
an
indu
ctor
has
no
inte
ntio
nal p
ath
to e
arth
/gro
und,
like
th
e ca
paci
tors
in a
fi lte
r, its
win
ding
s ha
ve s
igni
fi can
t stra
y ca
paci
tanc
e w
hich
will
hel
p co
ntro
l CM
cur
rent
s,
prov
idin
g th
e in
duct
or is
RF-
bond
ed.)
“RF-
bond
ing”
mea
ns p
rovi
ding
a
cond
uctiv
e pa
th th
at h
as a
ver
y lo
w im
peda
nce,
<<1
00m
Ω, a
t the
fre
quen
cy c
once
rned
. Ide
ally,
the
cond
uctiv
e pa
th s
houl
d ha
ve a
n im
peda
nce
of 1
mΩ
or l
ess
at th
e hi
ghes
t fre
quen
cy th
at it
is d
esire
d to
con
trol.
Rem
embe
r tha
t thi
s is
the
impe
danc
e of
a b
ond,
not
sim
ply
its
resi
stan
ce.
Wire
s or
bra
id s
traps
are
inef
fect
ive
for R
F-bo
ndin
g pu
rpos
es, b
ecau
se
thei
r im
peda
nce
is to
o gr
eat.
The
indu
ctiv
e im
peda
nce
of a
stra
ight
wire
is
2�ƒ
L, w
here
ƒ is
the
frequ
ency
to
be s
uppr
esse
d in
Her
tz (H
z) a
nd L
is
the
indu
ctan
ce o
f the
wire
in H
enrie
s (H
). W
e ca
n as
sum
e ab
out 1
μH/m
etre
fo
r a lo
ng w
ire a
nd a
bout
0.3
μH/m
etre
fo
r a w
ide
brai
d st
rap,
so,
for e
xam
ple,
at
1M
Hz
a 25
mm
wid
e br
aid
stra
p ju
st 1
00m
m lo
ng th
at m
ight
hav
e a
resi
stan
ce o
f 1m
Ω h
as a
n im
peda
nce
of n
early
0.2
Ω a
t 1M
Hz
– 20
to 2
00
times
too
high
to b
e a
good
RF-
bond
.
3031
of h
igh-
frequ
ency
noi
ses.
Eve
n w
here
the
chop
per d
oes
not
caus
e in
terfe
renc
e pr
oble
ms,
ther
e is
th
e pr
oble
m o
f bea
ring
life,
and
of t
he
degr
adat
ion
of th
e in
sula
tion
in m
otor
ca
bles
and
win
ding
s w
hen
long
mot
or
cabl
es a
re u
sed
(see
3.3
).Fig
ure
18
show
s an
alte
rnat
ive
to th
e ou
tput
fi l
ter s
how
n in
Fig
ure
15 –
a s
cree
ned
mot
or c
able
. As
this
fi gu
re s
how
s,
if th
e sc
reen
ed m
otor
cab
le h
as it
s sc
reen
cor
rect
ly R
F-bo
nded
at b
oth
ends
, the
CM
cur
rent
loop
s as
soci
ated
w
ith th
e V
FD’s
mot
or o
utpu
t pre
fer
to fl
ow in
side
the
cabl
e sc
reen
. Thi
s
is b
ecau
se th
e im
peda
nce
of th
e C
M
loop
pat
h do
wn
the
insi
de o
f the
cab
le
scre
en is
so
muc
h lo
wer
than
the
alte
rnat
ive
CM
loop
s th
at e
xist
in th
e ea
rth/g
roun
d st
ruct
ure.
For e
xam
ple,
whe
n a
num
ber o
f re
sist
ors
are
conn
ecte
d in
par
alle
l, it
is th
e on
e(s)
with
the
low
est v
alue
th
at c
arry
the
bulk
of t
he c
urre
nt.
The
impe
danc
e of
the
CM
loop
s at
fre
quen
cies
abo
ve a
kH
z or
so
are
dom
inat
ed b
y in
duct
ive
and
capa
citiv
e re
acta
nces
, rat
her t
han
resi
stan
ce,
but t
he s
ame
prin
cipl
e ap
plie
s –
the
bulk
of t
he C
M c
urre
nt a
utom
atic
ally
L1 L2 L3
Cho
pper
also
cal
led
switc
her
or in
verte
r
DC
Link
Rec
tifi
er6-
Pul
se ty
pesh
own
here
AC
Mot
or
M 3
“RF
bond
ed”:
to th
ech
oppe
r’s m
etal
enc
losu
reat
one
end
; and
to th
em
otor
fram
e at
the
term
inal
box
at t
he o
ther
end
Rec
tifie
r and
cho
pper
met
alen
clos
ures
mus
t be
RF-
bond
ed
Mai
nsIn
duct
orha
rmon
icsu
ppre
ssio
n
Mai
ns F
ilter
very
clo
seto
rect
ifier
nois
e su
ppre
ssio
nkH
z - M
Hz
Now
muc
h re
duce
d ha
rmon
ics,
DM
and
CM
noi
ses
flow
in th
e lo
ng m
ains
cab
le
Mos
t CM
noi
ses
now
flow
in m
uch
smal
ler l
oops
with
in th
e fil
ter/d
rive/
cabl
e as
sem
bly
The
DM
and
CM
noi
ses
flow
ing
in th
e lo
ng m
otor
ca
ble
mos
tly s
tay
insi
de it
DC
noi
se in
the
mai
ns s
uppl
yP
WM
noi
se c
onta
ined
with
in c
able
Filte
r mus
tbe
RF-
bond
edto
the
rect
ifier
’s
met
al e
nclo
sure
Scr
eene
d ca
ble,
or u
nscr
eene
d ca
ble
with
an
over
brai
d,or
with
a s
hiel
ding
cond
uit a
nd/o
rca
ble
arm
our
Figu
re 1
8:Su
ppre
ssio
n w
ith m
ains
indu
ctor
s an
d fi l
ters
, and
scr
eene
d m
otor
cab
les
I don
’t ha
ve a
real
-life
pho
togr
aph
of
an o
utpu
t fi lt
er in
stal
led
on a
VFD
, but
th
e pr
inci
ples
are
exa
ctly
the
sam
e as
for t
he m
ains
fi lte
r in
Figu
re 1
6.
The
outp
ut fi
lter s
houl
d be
one
that
, lik
e th
e m
ains
fi lte
r, re
dire
cts
both
the
DM
and
CM
noi
se c
urre
nts
that
wou
ld
othe
rwis
e fl o
w in
the
mot
or c
able
and
m
otor
, suc
h as
the
RE
O “S
inus
++”
, ot
herw
ise
know
n as
fi lte
r typ
e C
NW
961.
Fig
ure
15 d
oes
not s
how
it, b
ut
CM
+ D
M o
utpu
t fi lt
ers
like
the
CN
W
961
gene
rally
requ
ire a
con
nect
ion
to
the
DC
-Lin
k as
wel
l.
Figu
re 1
7 sh
ows
som
e re
al-li
fe
mea
sure
men
ts o
n a
VFD
fi tte
d w
ith
serie
s in
duct
ors
to li
mit
emis
sion
s of
mai
ns h
arm
onic
s, th
en w
ith a
n ad
ditio
nal fi
lter
to s
uppr
ess
emis
sion
s
RE
O c
ompo
nent
s ar
e av
aila
ble
that
com
bine
serie
s in
duct
ors
with
mai
ns fi
lters
VFD
mai
ns c
urre
ntsh
owin
g ha
rmon
ic n
oise
VFD
mai
ns v
olta
gesh
owin
g R
F no
ise
And
add
ing
a fil
ter r
educ
es th
eR
F no
ise
on th
e m
ains
vol
tage
Add
ing
a se
ries
indu
ctor
redu
ces
the
mai
ns h
arm
onic
cur
rent
s
Figu
re 1
7:Ex
ampl
es o
f sup
pres
sing
mai
ns n
oise
s
3233
Figu
re 1
9:D
etai
l of t
he m
otor
cab
le c
onne
ctio
n to
the
chop
per i
n Fi
gure
16
Bra
id-s
cree
ned
mot
or c
able
’s s
cree
n te
rmin
atio
n at
cho
pper
Use
s a
met
al s
addl
ecla
mp
that
bon
ds
to a
wid
e fl a
nge
exte
ndin
g fro
m th
e ch
assi
s of
the
chop
per’s
ele
ctro
nics
50kW
VS
D
Cho
pper
take
s th
e lo
op th
at p
rese
nts
the
leas
t ov
eral
l im
peda
nce.
To a
chie
ve th
e lo
w im
peda
nce
nece
ssar
y to
con
trol t
he m
otor
ou
tput
’s C
M c
urre
nts:
At t
he c
hopp
er e
nd, t
he m
otor
ca
ble
scre
en m
ust b
e R
F-bo
nded
to th
e ch
oppe
r’s m
etal
en
clos
ure,
cha
ssis
or f
ram
e.
At t
he m
otor
end
, the
mot
or
cabl
e sc
reen
mus
t be
RF-
bond
ed to
the
mot
or’s
met
al
term
inal
box
, whi
ch in
turn
mus
t be
RF-
bond
ed to
the
mot
or’s
en
clos
ure
or fr
ame
(e.g
. by
seam
-wel
ding
or m
ultip
le s
pot o
r ta
ck w
elds
).
Not
e: F
igur
e 18
doe
s no
t sho
w a
n ea
rth/g
roun
d ca
ble
betw
een
the
mot
or
body
and
the
chop
per,
alth
ough
one
w
ill a
lmos
t cer
tain
ly b
e re
quire
d. T
his
is b
ecau
se s
ome
VFD
man
ufac
ture
rs
requ
ire it
to b
e co
ntai
ned
with
in th
e sc
reen
of a
scr
eene
d m
otor
cab
le,
whe
reas
oth
er m
anuf
actu
rers
requ
ire
it to
be
rout
ed o
utsi
de th
e sc
reen
(but
st
ill c
lose
to th
e m
otor
cab
le a
long
its
rout
e). T
hese
requ
irem
ents
com
e fro
m th
e el
ectro
nic
desi
gn o
f the
V
FD, s
o it
is im
porta
nt to
obt
ain
the
man
ufac
ture
r’s E
MC
inst
ruct
ions
for
the
exac
t mod
el o
f mot
or d
rive,
and
fo
llow
them
.
A go
od w
ay to
pre
vent
noi
se fr
om
the
chop
per w
hich
is c
ausi
ng E
MC
prob
lem
s, is
to m
ake
the
mot
or
cabl
e ve
ry s
hort
inde
ed –
less
than
on
e-te
nth
of th
e w
avel
engt
h at
the
high
est s
igni
fi can
t cho
pper
har
mon
ic
frequ
ency
(e.g
. 1m
for 3
0MH
z, 1
0m
for 3
MH
z, 1
00m
for 3
00kH
z). T
he
very
bes
t is
to c
ombi
ne th
e B
DM
with
th
e m
otor
, with
thei
r met
al fr
ames
m
ulti-
poin
t RF-
bond
ed to
geth
er,
or c
ombi
ned
in a
com
mon
cas
ting,
so
ther
e is
no
exte
rnal
mot
or c
able
at
all.
Thi
s te
chni
que
has
been
ve
ry s
ucce
ssfu
lly u
sed
by s
ome
man
ufac
ture
rs, i
nclu
ding
Dan
foss
.
All
VFD
and
VS
D m
anuf
actu
rers
sh
ould
pro
vide
det
aile
d E
MC
in
stru
ctio
ns fo
r the
ir pr
oduc
ts. I
do
not
reco
mm
end
usin
g an
y m
anuf
actu
rer
who
doe
s no
t (or
will
not
) pro
vide
th
em. T
hey
will
ofte
n be
diff
eren
t for
di
ffere
nt m
odel
s an
d ra
tings
of d
rives
, an
d fo
r exa
mpl
e, h
ighe
r rat
ed d
rives
w
ill g
ener
ally
requ
ire d
iffer
ent fi
lter
sp
ecifi
catio
ns.
Cab
le s
cree
n R
F-bo
ndin
g is
so
met
imes
cal
led
360°
term
inat
ion
or 3
60°
bond
ing,
bec
ause
it s
houl
d id
eally
mak
e el
ectri
cal c
onne
ctio
n al
l ar
ound
the
circ
umfe
renc
e or
per
iphe
ry
of th
e br
aid
scre
en. A
ltern
ativ
es, s
uch
as m
ulti-
poin
t bon
ding
, may
be
used
pr
ovid
ing
the
bond
ing
poin
ts s
urro
und
the
cabl
e.
Figu
re 1
9 sh
ows
an a
mpl
ifi ed
det
ail
of F
igur
e 16
, whe
re th
e m
otor
cab
le
conn
ects
to th
e 50
kW V
FD’s
cho
pper
un
it. It
sho
ws
that
the
cabl
e’s
brai
d is
cl
ampe
d to
a fl
ange
pro
trudi
ng fr
om
the
chop
per’s
cha
ssis
, usi
ng a
met
al
sadd
lecl
amp.
3435
Figu
re 2
1:Ex
ampl
es o
f thr
ee k
inds
of E
MC
cab
le g
land
A lo
w-c
ost E
MC
Gla
nd fr
om H
umm
el(r
equi
res
the
shie
ld to
be
cut a
nd
care
fully
spr
ead
out,
so is
not
gen
eral
ly
appl
icab
le a
nd is
als
o su
scep
tible
to
qual
ity o
f wor
kman
ship
A hi
gh q
ualit
y ca
ble
glan
d fro
m
KE
C(u
ses
an ir
is s
prin
g to
mak
e an
ex
celle
nt R
F-bo
nd An
EM
C G
land
from
La
pp K
abel
(mul
ti-po
int s
hiel
d co
nnec
tion)
Figu
re 2
0 sh
ows
the
othe
r end
of t
he
mot
or c
able
in th
e sy
stem
driv
en b
y th
e V
FD in
Fig
ure
16. H
ere
the
mot
or
cabl
e’s
brai
d us
es a
n “E
MC
Gla
nd”
to 3
60°
bond
to th
e m
otor
’s te
rmin
al
box.
Fig
ure
21 s
how
s a
varie
ty o
f
type
s of
EM
C g
land
, the
top
left-
hand
on
e be
ing
the
pref
erre
d ty
pe. W
here
co
nnec
tors
are
use
d in
stea
d, th
ey
shou
ld te
rmin
ate
the
cabl
e sc
reen
in
360°
just
like
an
EM
C g
land
.
Figu
re 2
0:D
etai
l of t
he c
able
con
nect
ion
to th
e m
otor
driv
en b
y th
e VF
D o
f Fig
ure
16
Bra
id-s
cree
ned
mot
or c
able
’s s
cree
n te
rmin
atio
n at
mot
orU
ses
a 36
0O sc
reen
-bon
ding
cab
le
glan
d
3637
Figu
res
15 a
nd 1
8 sh
ow th
e D
M a
nd
CM
cur
rent
s fl o
win
g en
tirel
y w
ithin
th
e V
SD
ass
embl
y, w
hich
incl
udes
an
y m
ains
cho
kes
or fi
lters
, and
any
ou
tput
fi lte
rs a
nd/o
r mot
or c
able
sc
reen
bon
ds (a
t the
cho
pper
end
). H
owev
er, e
lect
rical
inst
alle
rs o
ften
seem
to b
e of
the
opin
ion
that
all
earth
s or
gro
unds
are
equ
ival
ent,
and
also
that
it d
oes
not m
atte
r exa
ctly
w
here
the
vario
us c
ompo
nent
s
asso
ciat
ed w
ith a
VS
D a
re in
stal
led
([37]
reco
rds
som
e di
ffi cu
lties
with
th
is).
So,
in p
ract
ice,
the
elec
trica
l in
stal
latio
n of
a V
SD
and
/or i
ts
asso
ciat
ed c
ompo
nent
s (c
hoke
s,
fi lte
rs, i
sola
ting
trans
form
ers,
mot
or
cabl
e sc
reen
bon
ds, e
tc.)
mig
ht n
ot
be c
ompa
ct, a
nd it
s ea
rth/g
roun
d co
nduc
tors
may
con
nect
all
over
the
plac
e.
Figu
re 2
3:Ex
ampl
e of
a s
uita
ble
360°
bon
d fo
r sol
id c
ondu
it
Whe
re it
is d
iffi c
ult t
o so
urce
hig
h-cu
rren
t cab
les
with
goo
d qu
ality
sc
reen
s, o
r whe
n su
ppre
ssin
g th
e no
ise
from
a le
gacy
sys
tem
that
us
ed a
n un
scre
ened
mot
or c
able
, ov
erbr
aids
or s
hiel
ded
fl exi
ble
cond
uit
can
be u
sed,
as
show
n in
Fig
ure
22.
Whe
n ch
oosi
ng e
ither
, mak
e su
re th
at
appr
opria
te 3
60°
glan
ds o
r con
nect
ors
are
avai
labl
e fo
r it.
Sol
id c
ondu
it m
akes
the
best
scr
een
for a
mot
or c
able
, but
the
usua
l “b
anjo
” was
hers
are
use
less
for
supp
ress
ion
purp
oses
bec
ause
they
re
ly o
n le
ngth
s of
wire
to b
ond
them
to
an e
arth
/gro
und
term
inal
, and
so
have
to
o hi
gh a
n im
peda
nce
at R
F. F
igur
e 23
sho
ws
one
man
ufac
ture
r’s s
olut
ion
– a
cond
uit n
ut th
at m
akes
a m
ulti-
poin
t 360
° bo
nd b
etw
een
the
solid
co
ndui
t and
a m
etal
enc
losu
re a
t the
po
int o
f pen
etra
tion
of th
e en
clos
ure.
Figu
re 2
2:Ex
ampl
es o
f scr
eene
d fl e
xibl
e co
ndui
t and
ove
rbra
id
3839
stru
ctur
e, u
sing
ver
y sh
ort
elec
tric
al b
onds
. Fol
low
all
the
nece
ssar
y sa
fety
cod
es ta
king
th
e ea
rth/
grou
nd le
akag
e cu
rren
t fro
m e
ach
into
acc
ount
(c
ould
be
seve
ral a
mps
, due
to
the
mai
ns fi
lterin
g).
4.4.
Mor
e de
tails
on
supp
ress
ing
PDS
emis
sion
sA
little
Gui
de li
ke th
is c
anno
t be
a te
xtbo
ok a
nd p
rovi
de e
very
thin
g on
e m
ight
nee
d to
kno
w, b
ut a
t lea
st it
can
pr
ovid
e th
e ba
sics
, and
this
has
bee
n do
ne a
bove
. Thi
s se
ctio
n pr
ovid
es
a fe
w a
dditi
onal
not
es, a
nd m
any
refe
renc
es, o
n su
ppre
ssin
g P
DS
em
issi
ons.
4.4.
1. O
btai
n m
anuf
actu
rer’s
EM
C in
stru
ctio
ns a
nd fo
llow
th
emV
FD a
nd V
SD
man
ufac
ture
rs E
MC
de
sign
/inst
alla
tion
guid
es s
houl
d al
way
s be
obt
aine
d, a
nd th
eir a
dvic
e fo
llow
ed a
ccur
atel
y. H
owev
er, t
hey
may
not
aim
to a
chie
ve th
e de
gree
of
nois
e su
ppre
ssio
n th
at is
nee
ded
(for
exam
ple
whe
n in
stal
ling
man
y P
DS
s in
one
sys
tem
, suc
h as
the
exam
ple
of
Figu
re 3
).
Ther
e ar
e m
any
gene
ral g
uide
s an
d te
xtbo
oks
on s
uppr
essi
ng e
mis
sion
s fro
m m
otor
driv
es, i
nclu
ding
[31]
, [32
], [3
3], [
34],
[35]
and
[36]
, and
thes
e m
ight
pro
vide
suf
fi cie
nt in
form
atio
n to
ove
rcom
e an
y sh
ortc
omin
gs in
the
driv
e m
anuf
actu
rer’s
EM
C in
stal
latio
n in
stru
ctio
ns. I
f eve
n m
ore
info
rmat
ion
is re
quire
d, s
ee th
e fo
llow
ing
subs
ectio
ns.
It is
how
ever
ver
y im
porta
nt in
deed
th
at th
e fo
llow
ing
two
gene
ral
inst
alla
tion
rule
s ar
e fo
llow
ed:
a) A
ll of
the
com
pone
nt p
arts
of
a VS
D, p
lus
its a
ssoc
iate
d su
ppre
ssio
n co
mpo
nent
s (c
hoke
s, fi
lters
, iso
latin
g tr
ansf
orm
ers,
mot
or c
able
sc
reen
bon
ds, e
tc.)
mus
t be
in
very
clo
se p
roxi
mity
, ide
ally
al
l con
tain
ed w
ithin
one
met
al
encl
osur
e.
b) A
ll of
the
eart
h/gr
ound
co
nduc
tors
ass
ocia
ted
with
th
e co
mpo
nent
par
ts in
a)
abov
e m
ust c
onne
ct to
one
po
int,
idea
lly th
e ch
assi
s,
fram
e, b
ackp
late
or s
urfa
ce
of th
e m
etal
cab
inet
they
are
al
l con
tain
ed w
ithin
. Th
is o
ne
poin
t mus
t the
n co
nnec
t to
the
site
’s o
r ves
sel’s
saf
ety
eart
h/gr
ound
str
uctu
re v
ia o
ne
cond
ucto
r – fo
llow
ing
all t
he
nece
ssar
y sa
fety
cod
es ta
king
th
e ea
rth/
grou
nd le
akag
e cu
rren
t int
o ac
coun
t (it
coul
d be
sev
eral
am
ps, d
ue to
the
mai
ns fi
lterin
g).
I mak
e no
apo
logy
for r
epea
ting
som
e of
the
poin
ts a
lread
y em
phas
ised
in
the
earli
er te
xt. E
lect
rical
inst
alle
rs
mus
t be
cont
rolle
d ve
ry c
aref
ully
to
ensu
re th
at th
ese
rule
s ar
e m
et in
fu
ll –
othe
rwis
e al
l the
tim
e an
d co
st
of d
eter
min
ing
how
to s
uppr
ess
the
driv
es w
ill b
e w
aste
d, a
nd th
e E
MC
engi
neer
s in
volv
ed w
ill b
e bl
amed
for
getti
ng it
wro
ng, w
hen
the
prob
lem
is
inco
rrec
t ins
talla
tion.
I stro
ngly
reco
mm
end
to a
ll E
MC
en
gine
ers
asso
ciat
ed w
ith s
uch
proj
ects
, tha
t the
y w
rite
dow
n m
anda
tory
requ
irem
ents
for t
he
inst
alla
tion
of th
eir s
uppr
essi
on
devi
ces,
usi
ng a
s m
uch
deta
il as
ne
eded
to c
omm
unic
ate
with
the
elec
trica
l ins
talle
rs in
term
s th
at th
ey
will
cle
arly
und
erst
and
– an
d in
sist
ing
that
the
cont
ract
with
the
cust
omer
in
clud
es a
n ite
m c
over
ing
thei
r in
spec
tion
and
appr
oval
of t
he fi
nal
elec
trica
l ins
talla
tion.
Som
e re
ader
s m
ight
con
trast
poi
nt b
) ab
ove
with
oth
er R
EO
Gui
des,
boo
ks
and
artic
les
I hav
e w
ritte
n (e
.g. [
19]
[26]
) in
whi
ch th
e vi
rtues
of m
eshe
d co
mm
on-b
ondi
ng n
etw
orks
(ME
SH
-C
BN
s) a
re e
xtol
led
at le
ngth
. Not
e th
at th
ese
also
allo
w th
e po
ssib
ility
of
com
bini
ng s
ingl
e-po
int b
onde
d sy
stem
s w
ith m
esh-
bond
ed o
nes,
so
ther
e is
no
confl
ict.
How
ever
, if a
M
ES
H-C
BN
or M
ES
H-IB
N (s
ee [1
9] o
r [2
6] fo
r defi
niti
ons)
that
can
con
trol u
p to
30M
Hz,
at l
east
, exi
sts
in th
e ar
ea
whe
re th
e V
SD
and
its
supp
ress
ion
com
pone
nts
are
loca
ted,
then
b) c
an
be m
odifi
ed to
read
as
follo
ws:
b*) A
ll of
the
eart
h/gr
ound
co
nduc
tors
ass
ocia
ted
with
th
e co
mpo
nent
par
ts in
a)
abov
e m
ust c
onne
ct to
thei
r lo
cal m
eshe
d C
BN
or I
BN
4041
phas
e C
M c
hoke
com
pone
nts
can
be
conn
ecte
d in
ser
ies.
Whe
n try
ing
to s
peci
fy y
our o
wn
mai
ns fi
lter i
n th
e ab
senc
e of
gui
danc
e fro
m th
e dr
ive
man
ufac
ture
r (or
whe
n th
at in
form
atio
n pr
oves
inad
equa
te)
it is
impo
rtant
to u
nder
stan
d th
at,
in re
al li
fe, m
ains
fi lte
rs o
pera
te
with
“mis
mat
ched
” inp
ut a
nd o
utpu
t im
peda
nces
– i.
e. th
ey a
re n
ot b
oth
50Ω
, or e
ven
both
the
sam
e. A
ll m
ains
fi lte
rs re
sona
te a
nd p
rovi
de
gain
rath
er th
an a
ttenu
atio
n at
thei
r re
sona
nt fr
eque
ncie
s, a
nd e
spec
ially
so
whe
n op
erat
ed m
ism
atch
ed
– as
they
alw
ays
are
in re
al-li
fe. B
ut
atte
nuat
ion
data
from
mos
t dis
tribu
ters
an
d so
me
man
ufac
ture
rs d
o no
t sho
w
this
, bec
ause
they
onl
y sh
ow th
e re
sults
of “
mat
ched
” tes
ts (i
.e. 5
0Ω
inpu
t and
out
put).
How
to d
eal w
ith th
e pr
oble
ms
of fi
lter
reso
nanc
e is
dis
cuss
ed in
det
ail i
n se
ctio
n 5.
10.1
of [
19],
4.7.
1 of
[20]
an
d C
hapt
er 8
.1.3
.1 o
f [26
]. Th
ese
all b
asic
ally
reco
mm
end
getti
ng
all t
he C
M a
nd D
M, m
atch
ed a
nd
mis
mat
ched
test
dat
a fro
m th
e fi l
ter
supp
lier (
6 cu
rves
in a
ll), d
raw
ing
the
wor
st c
ase
of a
ll of
the
atte
nuat
ion
curv
es, a
nd a
ssum
ing
that
a fi
lter’s
re
al-li
fe p
erfo
rman
ce w
ill b
e no
bet
ter
than
that
.
Cas
cadi
ng m
ains
fi lte
rs is
gen
eral
ly
a ba
d id
ea. R
eson
ance
s ca
n oc
cur
that
mak
e th
e at
tenu
atio
n of
the
com
bina
tion
wor
se th
an a
ny o
f the
fi lte
rs o
n th
eir o
wn,
so
grea
t car
e sh
ould
be
take
n w
hen
a V
FD is
fi tte
d w
ith a
n in
tern
al m
ains
fi lte
r, bu
t its
pe
rform
ance
is n
ot e
noug
h an
d yo
u ar
e te
mpt
ed to
add
ano
ther
fi lte
r in
serie
s w
ith it
.
How
ever
, mul
ti-st
age
fi lte
rs a
re
avai
labl
e th
at h
ave
exce
llent
pe
rform
ance
, alth
ough
the
mor
e st
ages
they
hav
e, th
e la
rger
, hea
vier
an
d m
ore
cost
ly th
ey te
nd to
be.
But
th
e au
thor
kno
ws
cust
om-e
ngin
eerin
g co
ntro
l cub
icle
man
ufac
ture
rs w
ho
auto
mat
ical
ly fi
t a 1
00A
3-ph
ase
5-st
age
mai
ns fi
lter t
o th
e in
com
ing
supp
ly o
f the
ir ca
bine
ts. A
lthou
gh
over
-spe
cifi e
d in
mos
t cas
es, t
hey
reck
on th
at it
sav
es th
em ti
me
and
cost
ove
rall,
by
avoi
ding
the
need
to
spe
nd ti
me
choo
sing
and
pro
ving
w
hich
is th
e m
ost c
ost-e
ffect
ive
fi lte
r fo
r eac
h ca
bine
t.
Mos
t sta
ndar
d m
ains
fi lte
rs s
old
as
‘EM
C fi
lters
’ will
not
pro
vide
muc
h at
tenu
atio
n fo
r the
VS
D’s
em
issi
ons
belo
w 1
50kH
z (s
ee th
e ca
se s
tudy
in
3.4)
. Filt
ers
suita
ble
for V
SD
s m
ust
prov
ide
good
atte
nuat
ion
dow
n to
the
chop
per’s
fund
amen
tal f
requ
ency
(i.e
. sw
itchi
ng fr
eque
ncy)
for b
oth
the
DM
an
d C
M n
oise
em
issi
ons.
The
CM
at
tenu
atio
n is
esp
ecia
lly im
porta
nt.
CM
+ D
M o
utpu
t fi lt
ers
conv
ert t
he
PW
M o
utpu
t int
o a
rela
tivel
y “c
lean
” D
C o
r AC
wav
efor
m, t
hat c
an b
e se
nt
sign
ifi ca
nt d
ista
nces
, ove
r per
fect
ly
ordi
nary
cab
les
to th
e m
otor
, with
out
4.4.
2. F
ilter
ing
The
spec
ifi ca
tions
for t
he fi
lters
sh
ould
be
obta
ined
from
the
VFD
or
VS
D m
anuf
actu
rer’s
det
aile
d E
MC
in
stru
ctio
ns fo
r exa
ctly
the
mod
el o
f dr
ive
bein
g us
ed. W
hen
not u
sing
an
outp
ut fi
lter,
long
er m
otor
cab
les
– or
sc
reen
ed o
r arm
oure
d m
otor
cab
les
– w
ill h
ave
mor
e st
ray
capa
cita
nce,
ca
usin
g an
incr
ease
in th
e m
agni
tude
of
the
chop
per’s
CM
cur
rent
s, a
nd
may
ther
efor
e ne
ed to
use
hig
her-
spec
ifi ca
tion
mai
ns fi
lters
for t
he s
ame
leve
l of e
mis
sion
s (a
ll el
se b
eing
the
sam
e).
So
the
mai
ns fi
lter s
peci
fi cat
ions
in a
pr
oper
ly d
ocum
ente
d E
MC
inst
alla
tion
guid
e sh
ould
sho
w h
ow th
e fi l
ter
spec
ifi ca
tions
dep
end
on th
e le
ngth
of
the
mot
or c
able
, and
in s
ome
case
s on
the
type
of c
able
too
(e.g
. scr
eene
d ca
ble,
or c
able
rout
ed in
con
duit,
will
ha
ve h
ighe
r stra
y ca
paci
tanc
e th
an
the
sam
e le
ngth
of u
nscr
eene
d).
For m
ore
info
rmat
ion
on E
MC
fi lte
ring,
an
d ho
w to
ass
embl
e it
in c
abin
ets,
sy
stem
s an
d in
stal
latio
ns to
get
max
i-m
um b
enefi
ts, s
ee s
ectio
n 5.
10 o
f [1
9], 4
.7 o
f [20
] and
Cha
pter
8 o
f [26
].
Mai
ns h
arm
onic
s ca
n be
fi lte
red,
in
stea
d of
sim
ply
redu
ced
by li
ne
indu
ctor
s. H
owev
er, b
ecau
se o
f the
ir lo
w fr
eque
ncie
s sp
ecia
l pas
sive
and
/or
act
ive
fi lte
ring
tech
niqu
es a
re u
sed,
an
d th
ese
are
disc
usse
d in
pag
es 5
1 th
roug
h 55
of [
29].
Whe
re R
F in
terfe
renc
e is
sus
pect
ed
from
a m
ains
or o
utpu
t cab
le, i
t will
us
ually
be
the
CM
cur
rent
s th
at a
re
to b
lam
e. C
lam
ping
a fe
rrite
toro
id
arou
nd a
ll of
the
phas
e an
d ne
utra
l co
nduc
tors
in th
e ca
ble
or b
undl
e, w
ith
or w
ithou
t inc
ludi
ng th
eir a
ssoc
iate
d pr
otec
tive
earth
ing
(saf
ety
grou
ndin
g)
cond
ucto
r, ca
n so
met
imes
be
enou
gh
to s
top
the
inte
rfere
nce,
and
is
espe
cial
ly e
ffect
ive
at fr
eque
ncie
s ab
ove
30M
Hz.
At f
requ
enci
es b
elow
30
MH
z tw
o or
mor
e fe
rrite
toro
ids
may
be
nee
ded
in s
erie
s on
the
cabl
e.
Dis
tribu
tors
sto
ck m
any
suita
ble
ferr
ite to
roid
s, a
nd th
e sp
lit v
ersi
ons
are
bette
r for
retro
fi ttin
g (a
ll E
MC
en
gine
ers
carr
y m
any
kilo
gram
s of
va
rious
type
s of
ferr
ite w
hen
visi
ting
a si
te to
try
to s
olve
a p
robl
em).
It is
impo
rtant
to e
nsur
e th
at a
ll of
th
e po
wer
con
duct
ors
asso
ciat
ed
with
a m
ains
sup
ply
or m
otor
load
pa
ss th
roug
h th
e fe
rrite
toro
id, a
nd
it m
ay b
e ne
cess
ary
to w
ind
thos
e co
nduc
tors
two
or e
ven
thre
e tim
es o
n th
e to
roid
. Alw
ays
chec
k th
at –
whe
n in
stal
led
on a
cab
le –
the
ferr
ites
do
not g
et to
o ho
t to
hold
you
r han
d on
fo
r sev
eral
min
utes
, whe
n th
e dr
ive
is ru
nnin
g at
full
pow
er. I
deal
ly, th
ey
wou
ld h
ardl
y ge
t war
m a
t all,
and
if
they
do
it us
ually
mea
ns th
at a
muc
h la
rger
ferr
ite is
requ
ired.
For e
ven
bette
r per
form
ance
from
a
ferr
ite C
M fi
lter a
t low
freq
uenc
ies,
w
ound
sin
gle-
phas
e an
d th
ree-
4243
Shi
ps a
nd o
ther
ves
sels
gen
eral
ly
use
mai
ns s
uppl
ies
that
do
not h
ave
thei
r neu
tral d
irect
ly b
onde
d to
thei
r ea
rth/g
roun
d st
ruct
ure
[35]
, and
som
e la
nd-b
ased
inst
alla
tions
als
o us
e th
is
prac
tice.
Thi
s si
tuat
ion
is d
iscu
ssed
in
Sec
tion
4.5.
4.4.
3. S
afet
y is
sues
with
fi l
terin
gFi
lters
con
tain
cap
acito
rs fr
om th
e ph
ase
cond
ucto
rs (m
ains
or m
otor
) to
the
earth
/gro
und,
and
thes
e in
crea
se th
e cu
rren
t in
the
prot
ectiv
e ea
rthin
g co
nduc
tor (
the
gree
n/ye
llow
st
riped
wire
in th
e m
ains
sup
ply)
. S
afet
y st
anda
rds
and
elec
trica
l w
iring
cod
es s
et q
uite
low
lim
its o
n th
is c
urre
nt, t
o he
lp p
reve
nt e
lect
ric
shoc
k ha
zard
s, b
ut th
ey w
ill a
llow
an
y am
ount
of e
arth
/gro
und
leak
age
curr
ent w
hen
high
-inte
grity
ear
thin
g/gr
ound
ing
syst
ems
are
used
with
a
fi xed
VS
D in
stal
latio
n (i.
e. o
ne th
at
does
not
hav
e a
fl exi
ble
mai
ns le
ad o
r m
ains
plu
g, s
omet
imes
cal
led
“non
-pl
ugga
ble”
equ
ipm
ent.)
.
The
high
ear
th/g
roun
d le
akag
e cu
rren
ts c
ause
d by
fi lte
rs c
an a
lso
mak
e it
impo
ssib
le to
use
resi
dual
-cu
rren
t circ
uit b
reak
ers
(RC
CB
s),
earth
leak
age
circ
uit b
reak
ers
(ELC
Bs)
or g
roun
d-fa
ult i
nter
rupt
ers
(GFI
s).
Whe
re th
e m
ains
sys
tem
is is
olat
ed
from
the
safe
ty e
arth
/gro
und
(see
4.5
),
or w
hen
it is
“cor
ner-
grou
nded
” (on
e ph
ase
conn
ecte
d to
ear
th/g
roun
d,
rath
er th
an th
e ne
utra
l), a
ll ca
paci
tors
co
nnec
ted
to th
e ea
rth/g
roun
d (e
.g.
in a
fi lte
r) s
houl
d be
saf
ety-
rate
d fo
r th
e fu
ll ph
ase-
to-p
hase
vol
tage
, rat
her
than
pha
se-to
-neu
tral.
4.4.
4. B
enefi
ts o
f iso
latin
g tr
ansf
orm
ers
Whe
re a
BD
M is
not
pow
ered
from
a
co-lo
cate
d de
dica
ted
step
-dow
n is
olat
ing
mai
ns tr
ansf
orm
er, a
nd
whe
re th
e m
ains
pow
er s
uppl
y th
at
feed
s it
is s
hare
d w
ith o
ther
ele
ctro
nic
equi
pmen
t (w
hich
may
incl
ude
othe
r B
DM
s) th
at a
re n
ot c
o-lo
cate
d w
ith
the
BD
M c
once
rned
– th
en a
num
ber
of E
MC
issu
es a
rise
that
may
be
best
dea
lt w
ith b
y fi t
ting
the
BD
M
with
a d
edic
ated
co-
loca
ted
isol
atin
g tra
nsfo
rmer
.
Isol
atin
g tra
nsfo
rmer
s ar
e la
rge
and
cost
ly c
ompo
nent
s, e
spec
ially
for
high
-pow
er B
DM
s, b
ut o
mitt
ing
them
or
tryi
ng to
use
less
cos
tly a
ltern
ativ
es
can
prov
e to
be
mor
e co
stly
ove
rall
(see
sec
tion
3).
In s
ituat
ions
whe
re a
mai
ns p
ower
su
pply
feed
s tw
o or
mor
e ite
ms
of
equi
pmen
t spr
ead
over
a s
ite o
r ve
ssel
, the
DM
impe
danc
es o
f the
ph
ases
can
bec
ome
diffe
rent
from
ea
ch o
ther
due
to u
nequ
al lo
adin
g,
and
the
CM
impe
danc
e be
twee
n th
e ph
ases
and
the
earth
/gro
und
can
caus
ing
inte
rfere
nce
prob
lem
s –
inci
dent
ally
impr
ovin
g ca
ble
and
mot
or
life
as m
entio
ned
earli
er. B
ut b
ecau
se
they
are
cos
tly, s
uch
outp
ut fi
lters
w
ill p
roba
bly
not e
ven
be m
entio
ned
in m
ost d
rive
man
ufac
ture
rs’ E
MC
in
stru
ctio
ns.
Whe
re u
sing
scr
eene
d m
otor
cab
les
is im
prac
tical
for s
ome
reas
on,
CM
+, D
M fi
lters
like
RE
O’s
Sin
us +
+ se
ries
may
be
the
only
sol
utio
n. T
he
man
ufac
ture
rs o
f the
fi lte
rs s
houl
d be
able
to te
ll yo
u w
hich
VFD
s or
VS
Ds
they
are
sui
tabl
e fo
r.
In b
etw
een
low
-cos
t fer
rite
toro
ids
and
expe
nsiv
e C
M +
DM
mot
or o
utpu
t fi l
ters
, the
re a
re v
ario
us m
ediu
m-c
ost
alte
rnat
ives
. So-
calle
d dV
/dt fi
lter
s “r
ound
off”
the
edge
s of
the
mot
or
outp
ut P
WM
wav
efor
ms,
whi
ch –
in
the
frequ
ency
dom
ain
– at
tenu
ates
th
e hi
gher
freq
uenc
y no
ise
spec
trum
. Fi
gure
24
show
s th
e ef
fect
of a
pply
ing
a R
EO
dV
/dt o
utpu
t fi lt
er to
a V
FD.
Ris
ing
edge
of P
WM
out
put
wav
efor
m fr
om a
VFD
The
sam
e VF
D o
utpu
tw
avef
orm
with
a R
EO
CN
W 8
11 “d
V/dt
filte
r” fit
ted
Figu
re 2
4:“R
ound
ing
off”
the
PWM
wav
efor
m w
ith a
dV/
dt fi
lter
4445
Ant
i-vib
ratio
n de
vice
,e.
g. A
nti-v
ibra
tion
was
her
or o
ther
met
hod
But
nev
er u
se c
hem
ical
‘thre
ad-lo
ck’
Not
e: th
is R
F-bo
ndis
sho
wn
parti
ally
disa
ssem
bled
Met
al c
ompo
nent
s to
be R
F-bo
nded
Rel
iabl
e R
F-bo
nds
re c
reat
ed b
y pr
essi
ngto
geth
er h
ighl
y-co
nduc
tive
met
al s
urfa
ces
Mat
eria
ls s
houl
d be
cho
sen
to p
reve
ntox
idat
ion
or c
orro
sion
ove
r the
life
cycl
e,ta
king
the
real
-life
env
ironm
ent i
nto
acco
unt
Any
insu
latin
g fin
ishe
sre
mov
ed fr
om e
ntire
bond
ing
area
(e.g
. pai
nt, a
nodi
sing
,po
lym
er p
assi
vatio
n)
Con
duct
ive
gask
ets
coul
d be
inse
rted
here
Do
not r
ely
on s
crew
thre
ads
of a
ny ty
pe to
mak
e th
e R
F-bo
nds
Figu
re 2
5: R
F-bo
ndin
g tw
o m
etal
sur
face
s
beco
me
quite
low
due
to th
e st
ray
capa
cita
nces
of t
he lo
ng c
able
s an
d th
e C
M fi
lters
in o
ther
equ
ipm
ent.
Thes
e im
peda
nce
effe
cts
nega
tivel
y af
fect
the
perfo
rman
ce o
f a B
DM
’s
mai
ns fi
lter (
see
[36]
). Fi
tting
an
isol
atin
g tra
nsfo
rmer
rest
ores
the
bala
nce
to th
e D
M im
peda
nces
, and
al
so re
stor
es a
hig
h C
M im
peda
nce,
he
lpin
g th
e m
ains
fi lte
r ach
ieve
its
desi
gned
pot
entia
l.
Ear
lier,
I dis
cuss
ed h
ow a
BD
M’s
C
M re
turn
cur
rent
s w
ere
‘ste
ered
’ by
capa
cito
rs in
its
inpu
t and
/or o
utpu
t fi l
ters
and
thei
r low
-impe
danc
e bo
ndin
g to
the
BD
M’s
cha
ssis
/fram
e,
so th
at th
ey fl
owed
mos
tly in
the
BD
M’s
ass
embl
y. B
ut w
hen
the
CM
im
peda
nce
of th
e m
ains
sup
ply
is lo
w th
e ra
tio b
etw
een
the
path
im
peda
nces
pro
vide
d by
the
mai
ns
fi lte
r and
that
pro
vide
d by
the
mai
ns
supp
ly m
ight
not
be
as h
igh
as w
e w
ould
like
. For
exa
mpl
e, w
here
ther
e ar
e tw
o or
mor
e eq
uipm
ents
fi tte
d w
ith
mai
ns fi
lters
con
nect
ed to
a m
ains
su
pply,
thei
r low
CM
impe
danc
es
enco
urag
e th
e C
M c
urre
nts
of e
ach
item
of e
quip
men
t to
fl ow
in th
e ot
her’s
mai
ns fi
lter –
enc
oura
ging
CM
cu
rren
ts to
fl ow
wid
ely,
whi
ch is
not
w
hat w
e w
ant.
Whe
re a
BD
M’s
mai
ns fi
lter d
oes
not
incl
ude
a C
M c
hoke
on
the
supp
ly
side
of i
ts C
M c
apac
itors
, thi
s pr
oble
m
can
be re
duce
d by
fi tti
ng a
CM
cho
ke
in th
at p
ositi
on, c
o-lo
cate
d w
ith th
e
mai
ns fi
lter.
But
all
chok
es c
ause
so
me
volta
ge d
rop
and
so th
is m
ight
ca
use
an in
crea
sed
rate
of t
rippi
ng
due
to s
ags
or d
ips
in th
e su
pply.
A
noth
er p
ossi
bilit
y is
to fi
t an
earth
/gr
ound
cho
ke to
the
BD
M, w
hich
of
cour
se w
ill o
nly
wor
k if
it is
fi tte
d to
th
e si
ngle
con
duct
or th
at c
onne
cts
the
BD
M’s
ear
th/g
roun
d to
the
earth
/gr
ound
stru
ctur
e of
the
site
or v
esse
l (s
ee it
em b
in S
ectio
n 4.
3).
But
an
isol
atin
g tra
nsfo
rmer
ded
icat
ed
to th
e B
DM
and
co-
loca
ted
with
it
(see
item
a in
sec
tion
4.3)
will
pro
vide
m
uch
bette
r con
trol o
f CM
cur
rent
s th
an a
ny c
hoke
s.
A m
ains
isol
atin
g tra
nsfo
rmer
mig
ht
also
pro
ve to
be
suffi
cien
t, on
its
own
with
out a
mai
ns fi
lter,
for p
reve
ntin
g th
e C
M n
oise
from
a B
DM
’s m
ains
in
put f
rom
circ
ulat
ing
wid
ely.
It w
ould
do
littl
e or
not
hing
for t
he B
DM
’s D
M
nois
e em
issi
ons,
or t
he re
sulti
ng
wav
efor
m d
isto
rtion
, but
this
is o
ften
not a
s m
uch
of a
pro
blem
as
the
CM
no
ise
emis
sion
s an
yway
.
Whe
re a
BD
M is
fi tte
d w
ith a
mai
ns
fi lte
r tha
t dea
ls w
ith C
M n
oise
as
wel
l as
DM
, the
maj
ority
of p
robl
ems
with
wid
ely-
circ
ulat
ing
CM
cur
rent
s oc
cur a
t low
er fr
eque
ncie
s, b
elow
15
0kH
z. In
this
cas
e ex
perie
nce
seem
s to
sho
w th
at th
e no
rmal
ty
pe o
f con
stru
ctio
n fo
r an
isol
atin
g tra
nsfo
rmer
is a
dequ
ate
for c
ontro
lling
C
M c
urre
nts
in th
is fr
eque
ncy
rang
e.
How
ever
, the
re a
re te
chni
ques
av
aila
ble
for d
ecre
asin
g th
e st
ray
prim
ary-
seco
ndar
y in
terw
indi
ng
capa
cita
nce,
and
for a
ddin
g in
terw
indi
ng s
cree
ns. T
hese
can
be
use
d to
pro
vide
bet
ter i
sola
tion
perfo
rman
ce a
nd h
ighe
r CM
sou
rce
impe
danc
e, fr
om D
C to
radi
o fre
quen
cies
, whi
ch m
ay b
e ne
eded
on
occa
sion
, for
exa
mpl
e w
hen
a m
ains
fi l
ter i
s no
t fi tt
ed a
t all.
4.4.
5. M
ore
deta
il on
RF-
bond
ing
tech
niqu
esFi
gure
25
show
s th
e ba
sics
of t
he
idea
l met
hod
of R
F-bo
ndin
g tw
o m
etal
item
s to
geth
er (e
.g. R
F-bo
ndin
g th
e m
etal
bod
ies
of th
e m
ains
fi lte
r, re
ctifi
er a
nd c
hopp
er to
the
back
plat
e in
Fig
ure
16).
But
ther
e ar
e m
any
mor
e de
tails
th
at c
ould
be
impo
rtant
, and
in
som
e ca
ses
alte
rnat
ives
mig
ht b
e ap
prop
riate
, so
the
info
rmat
ion
in
4647
4.4.
7. S
cree
ned
(shi
elde
d)
encl
osur
esE
N/IE
C 6
1800
-3 is
rath
er d
ism
issi
ve
of th
e po
tent
ial o
f PD
Ss
to in
terfe
re
with
radi
o re
cept
ion
thro
ugh
radi
ated
em
issi
ons.
How
ever
, VFD
s –
espe
cial
ly lo
w-p
ower
one
s sw
itchi
ng
at o
ver 2
0kH
z –
have
bee
n kn
own
to
inte
rfere
with
radi
ocom
mun
icat
ions
, as
som
e ite
ms
in [1
5] s
how
(e.g
. No.
24
).
As
long
ago
as
the
early
199
0s I
have
had
to im
prov
e th
e sh
ield
ing
of in
dust
rial c
ontro
l cab
inet
s th
at
cont
aine
d se
vera
l VFD
s, to
pas
s th
e ra
diat
ed e
mis
sion
test
s to
the
gene
ric
emis
sion
s st
anda
rd fo
r the
indu
stria
l en
viro
nmen
t (w
hich
was
EN
500
82-1
,
but i
s no
w E
N/IE
C 6
1000
-6-4
). E
ach
VFD
com
plie
d on
its
own,
but
whe
n al
l th
e dr
ives
in th
e ca
bine
t wer
e ru
nnin
g,
thei
r agg
rega
te e
mis
sion
s w
ere
sign
ifi ca
ntly
abo
ve th
e lim
it lin
e.
As
Pow
erFE
Ts a
nd IG
BTs
dev
elop
, th
ey a
re d
esig
ned
to s
witc
h fa
ster
to
redu
ce h
eat l
osse
s an
d in
crea
se
effi c
ienc
y, s
o th
e pr
ospe
cts
for
radi
ated
inte
rfere
nce
can
only
wor
sen.
A
nd a
s m
entio
ned
in s
ectio
n 3,
mor
e ra
dioc
omm
unic
atio
ns a
re b
eing
use
d ev
eryw
here
, whi
ch a
lso
incr
ease
s th
e po
tent
ial f
or ra
diat
ed in
terfe
renc
e fro
m
PD
Ss.
Des
igni
ng a
nd/o
r ins
talli
ng s
hiel
ded
encl
osur
es re
quire
s a
lot o
f atte
ntio
n to
det
ail,
but t
he b
asic
prin
cipl
es a
re
outli
ned
in F
igur
e 27
, whi
ch s
how
s
Cho
pper
Scr
eene
d B
DM
enc
losu
reM
otor
Scr
eene
d ca
bles
mus
tha
ve 3
60O R
F-bo
ndin
gco
nnec
tors
or g
land
sat
bot
h en
ds
Uns
hiel
ded
cabl
esm
ust a
ll be
filte
red
byth
roug
h-bu
lkhe
ad fi
lters
All
cabl
esro
uted
clo
seto
the
PE
C
Filte
rs
The
Par
alle
l Ear
th C
ondu
ctor
‘PE
C’ (
e.g.
a c
able
tray
)
Figu
re 2
7:Th
e ba
sic
prin
cipl
es o
f em
ploy
ing
a sc
reen
ed e
nclo
sure
Two
strip
s of
sof
t con
duct
ive
gask
et c
reat
e 36
0O
RF-
bond
s be
twee
n th
e ca
bles
’ scr
eens
and
the
high
ly-c
ondu
ctiv
e su
rface
of t
he c
hopp
er’s
met
alen
clos
ure,
cha
ssis
or f
ram
e - w
hen
the
clam
ping
plat
e is
tigh
tene
d do
wn.
Scr
eene
d ca
bles
ent
erin
g/le
avin
g th
e B
DM
(Stra
in re
lief a
nd e
nviro
nmen
tal s
ealin
g no
t sho
wn)
Met
al c
lam
ping
pla
teC
able
scr
eens
exp
osed
to m
ake
good
con
tact
with
the
gask
ets
Figu
re 2
6:A
low
-cos
t way
to R
F-bo
nd m
ultip
le c
able
scr
eens
sect
ion
5.7
of [1
9], 2
.2 th
roug
h 2.
5 of
[20]
and
Cha
pter
5 o
f [26
] may
be
usef
ul.
4.4.
6. M
ore
deta
il on
cab
le
scre
enin
g (s
hiel
ding
) te
chni
ques
This
will
be
foun
d in
sec
tions
5.7
.6
thro
ugh
5.7.
10 a
nd 5
.11
of [1
9], 3
.7 o
f [2
0] a
nd C
hapt
er 7
.2 o
f [26
].
Scr
een
bond
ing
need
not
be
cost
ly,
espe
cial
ly w
here
ther
e ar
e nu
mbe
r of
cab
les
scre
ens
to b
e bo
nded
(e.g
. to
a c
abin
et b
ackp
late
) as
show
n by
the
DIY
scr
een-
bond
ing
tech
niqu
e of
Fi
gure
26.
How
ever
, whe
re a
scr
eene
d en
clos
ure
(e.g
. cab
inet
, roo
m, e
tc.)
is u
sed
(see
4.
4.5)
, “pr
oper
” gla
nds
like
the
top
left-
hand
sid
e on
in F
igur
e 21
sho
uld
alw
ays
be u
sed
(or c
onne
ctor
s w
ith
sim
ilar s
cree
ned
brai
d te
rmin
atio
ns).
4849
whi
nes
and
whi
stle
s if
rout
ed to
o cl
ose
to c
able
s as
soci
ated
with
a d
rive,
and
ar
e a
mat
ter o
f som
e co
ncer
n to
EN
/IE
C 6
1800
-3 (s
ee 6
.2.5
in [1
]). F
or a
re
al-li
fe e
xam
ple
of s
erio
us te
leph
one
inte
rfere
nce
from
a h
igh-
pow
er d
rive,
se
e Ite
m 1
in [1
5].
Cab
le c
lass
ifi ca
tion
and
segr
egat
ion
is c
over
ed in
sec
tion
4.8
of [1
9] (4
.4
is a
lso
impo
rtant
); 3.
3 of
[20]
and
C
hapt
er 7
.4 o
f [26
].
4.4.
9. C
omm
utat
ion
notc
hes
Volta
ge “n
otch
ing”
is a
n em
issi
on
prob
lem
cau
sed
by n
atur
ally
co
mm
utat
ed th
yris
tors
/tria
cs in
DC
dr
ives
. The
cro
ss-c
ondu
ctio
n w
hen
one
thyr
isto
r or t
riac
turn
s on
bef
ore
anot
her h
as fi
nish
ed tu
rnin
g of
f, m
omen
taril
y sh
orts
-out
thei
r pha
ses
caus
ing
a di
p w
ith a
dep
th o
f 100
%.
Alth
ough
this
is a
low
-freq
uenc
y no
ise,
it is
ver
y se
vere
and
can
in
terfe
re w
ith o
ther
equ
ipm
ent t
hat
is u
sing
thos
e ph
ases
. How
ever
, a
“3%
indu
ctor
” suc
h as
is o
ften
fi tte
d to
redu
ce e
mis
sion
s of
mai
ns
harm
onic
s an
d in
terh
arm
onic
s (s
ee
4.4.
8), w
ill g
ener
ally
pro
vide
ade
quat
e su
ppre
ssio
n.
[1] c
alls
this
ser
ies
indu
ctor
a
“dec
oupl
ing
reac
tanc
e” a
nd re
quire
s th
at it
s si
ze b
e sp
ecifi
ed.
4.4.
10.
Mai
ns h
arm
onic
s an
d in
terh
arm
onic
sTh
ese
are
typi
cally
sup
pres
sed
by
usin
g a
“3%
indu
ctor
” in
serie
s w
ith
the
rect
ifi er
, as
show
n in
Fig
ures
15
and
16. T
he 3
% re
fers
to th
e fa
ct th
at
whe
n ca
rryi
ng it
s fu
ll ra
ted
curr
ent,
its
inte
rnal
impe
danc
e re
duce
s th
e m
ains
vo
ltage
by
3%. T
his
is c
onsi
dere
d to
be
a co
st-e
ffect
ive
com
prom
ise,
bu
t som
etim
es it
is n
eces
sary
to g
o as
hig
h as
a 4
% in
duct
or. I
ncre
asin
g th
e im
peda
nce
even
furth
er is
not
ad
vise
d, s
o if
serie
s in
duct
ors
have
no
t man
aged
to re
duce
the
harm
onic
an
d in
terh
arm
onic
em
issi
ons
by
enou
gh, o
ther
tech
niqu
es m
ust b
e us
ed in
stea
d of
, or a
s w
ell a
s, s
erie
s in
duct
ors.
Sin
gle-
phas
e V
SD
s an
d V
FDs
suffe
r fro
m e
mitt
ing
all o
f the
odd
-nu
mbe
red
mai
ns h
arm
onic
s, in
clud
ing
tripl
ens
as m
entio
ned
earli
er.
On
four
wire
sys
tem
s (i.
e. 3
pha
se +
N)
the
tripl
ens
add
arith
met
ical
ly in
the
neut
ral c
ondu
ctor
cau
sing
sig
nifi c
ant
prob
lem
s w
ith lo
calis
ed p
ower
qua
lity
and
equi
pmen
t ope
ratio
n.
How
ever
, th
ree-
phas
e (6
pul
se) d
rives
runn
ing
from
reas
onab
ly lo
w-d
isto
rtion
mai
ns
supp
lies
have
ver
y lo
w le
vels
of
“trip
len”
har
mon
ics,
of w
hich
the
mos
t im
porta
nt a
re th
e 3rd
and
9th. L
osin
g th
e 3rd
mak
es it
eas
ier t
o us
e se
ries
indu
ctor
s to
get
goo
d le
vels
of m
ains
ha
rmon
ic re
duct
ion.
that
no
cond
ucto
r of a
ny ty
pe (e
ven
a m
echa
nica
l pus
h-ro
d or
met
al p
ipe)
ca
n en
ter/e
xit a
scr
eene
d en
clos
ure
with
out e
ither
:
a) B
eing
RF-
bond
ed to
the
encl
osur
e’s
met
al w
all a
t the
poi
nt o
f en
try/e
xit,
or
b) B
eing
fi lte
red
to a
n ap
prop
riate
sp
ecifi
catio
n, w
ith th
e fi l
ter R
F-bo
nded
to
the
encl
osur
e’s
met
al w
all a
t the
po
int o
f ent
ry/e
xit,
or
c) B
eing
a s
cree
ned
cabl
e w
ith a
n ap
prop
riate
spe
cifi c
atio
n, th
e sc
reen
be
ing
RF-
bond
ed (i
.e. 3
60°
bond
ed)
to th
e en
clos
ure’
s m
etal
wal
l at t
he
poin
t of e
ntry
/exi
t.
No
alte
rnat
ives
are
eve
r per
mitt
ed, f
or
any
reas
on. I
am
ofte
n as
ked
to s
olve
re
al-li
fe p
robl
ems
in w
hich
exp
ensi
ve
shie
lded
cab
inet
s ar
e fo
und
to b
e “le
akin
g”, a
nd th
e us
ual p
robl
em is
th
at s
ome
cond
ucto
r ass
umed
to
be in
sign
ifi ca
nt (e
.g. h
ydra
ulic
pip
e,
mou
se c
able
, etc
.) ha
s be
en a
llow
ed
to e
nter
/exi
t the
enc
losu
re w
ithou
t on
e of
the
abov
e th
ree
met
hods
bei
ng
appl
ied.
How
ever
, som
etim
es th
e pr
oble
m h
as
been
that
the
syst
em in
tegr
ator
has
si
mpl
y cu
t a la
rge
hole
in th
e w
all o
r do
or o
f the
scr
eene
d en
clos
ure,
to
mou
nt th
eir h
uman
-mac
hine
inte
rface
, de
stro
ying
the
scre
enin
g ef
fect
iven
ess
in th
e pr
oces
s.
A gr
eat d
eal o
f det
ail o
n th
e de
sign
and
inst
alla
tion
of s
hiel
ded
encl
osur
es, o
f all
size
s fro
m ju
st la
rge
enou
gh fo
r one
sm
all V
FD, u
p to
sc
reen
ing
an e
ntire
room
or e
ven
a bu
ildin
g, w
ill b
e fo
und
in th
e fo
llow
ing:
se
ctio
n 5.
12 o
f [19
], se
ctio
n 5
of [2
0]
and
Cha
pter
6 o
f [26
].
4.4.
8. O
ther
EM
C te
chni
ques
The
abov
e di
scus
sion
has
not
ad
dres
sed
all t
he E
MC
tech
niqu
es
that
will
pro
babl
y be
requ
ired,
for
whi
ch re
ad [3
1] [3
2] [3
3] [3
4] [3
6] a
nd
[19]
[20]
and
[26]
.
For e
xam
ple,
mos
t (if
not a
ll) V
FD
man
ufac
ture
r’s E
MC
inst
alla
tion
inst
ruct
ions
, as
wel
l as
[33]
[34]
and
[3
6] w
ill in
clud
e th
e re
quire
men
t to
clas
sify
the
cabl
es a
ssoc
iate
d w
ith
a P
DS
acc
ordi
ng to
som
e ru
les,
and
th
en to
rout
e th
ese
“cab
le c
lass
es”
sepa
rate
ly fr
om e
ach
othe
r, w
ith
certa
in m
inim
um s
paci
ngs
to b
e m
aint
aine
d be
twee
n ca
ble
clas
ses
whe
re th
ey a
re ro
uted
in p
aral
lel.
This
ack
now
ledg
es th
e fa
ct th
at n
o ca
ble
scre
ens
or fi
lters
are
per
fect
, so
it h
elps
to re
duce
the
cros
stal
k be
twee
n th
e ca
bles
, esp
ecia
lly fr
om
the
mot
or o
utpu
t to
the
mai
ns s
uppl
y or
con
trol c
able
s. It
als
o he
lps
ensu
re
low
cro
ssta
lk to
cab
les
that
are
not
as
soci
ated
with
the
driv
e, s
uch
as
tele
phon
e ca
bles
, whi
ch c
an s
uffe
r dr
amat
ical
ly fr
om a
udio
-freq
uenc
y
5051
is re
ally
a c
hopp
er th
at is
con
trolle
d to
sou
rce
or s
ink
mai
ns c
urre
nts
in
antip
hase
to th
ose
that
are
cau
sing
pr
oble
ms,
and
– d
espi
te it
s na
me
– is
no
t a fi
lterin
g te
chni
que
at a
ll. P
assi
ve
and
activ
e ha
rmon
ic fi
lters
are
ofte
n us
ed w
here
it is
des
ired
to d
eal w
ith
the
harm
onic
s of
all
the
equi
pmen
t on
one
fl oo
r of a
bui
ldin
g, o
r eve
n an
en
tire
build
ing,
site
or v
esse
l, in
stea
d of
dea
ling
with
them
at t
he le
vel o
f in
divi
dual
item
s of
equ
ipm
ent.
Act
ive
fi lte
rs, i
ntro
duce
d so
me
10
year
s ag
o, a
re e
xpen
sive
but
wid
ely
used
. Th
ese
elec
troni
c ‘fi
lters
’ pro
vide
a
very
low
impe
danc
e so
urce
(<1%
) fo
r the
har
mon
ic c
urre
nts.
The
refo
re,
if ra
ted
corr
ectly
, the
load
(s) d
raw
the
harm
onic
cur
rent
s fro
m th
e ac
tive
fi lte
r whi
lst t
he s
ourc
e pr
ovid
es o
nly
the
fund
amen
tal c
urre
nt.
Dep
endi
ng
on th
e ty
pe, a
ctiv
e fi l
ters
can
redu
ce
harm
onic
em
issi
ons
to b
elow
5%
. A
ctiv
e fi l
ters
are
par
alle
l dev
ices
, an
d so
onl
y ne
ed to
be
rate
d fo
r the
ha
rmon
ic c
urre
nt.
The
othe
r typ
e of
har
mon
ic fi
lter
whi
ch is
ver
y po
pula
r is
wor
ldw
ide
the
pass
ive
“wid
e sp
ectru
m fi
lter”
. Th
ese
are
mul
ti-lim
bed
reac
tors
w
ound
on
a co
mm
on c
ore,
fi tte
d w
ith a
sm
all c
apac
itor b
ank
(not
like
tra
ditio
nal p
assi
ve fi
lters
). Th
ey a
re
conn
ecte
d in
ser
ies
with
the
load
(s)
and
– de
pend
ing
on m
anuf
actu
rer
– ca
n al
so re
duce
the
I thd t
o ar
ound
5%
. O
ne m
anuf
actu
rer s
uppl
ies
thes
e
fi lte
rs u
p to
alm
ost 3
,000
kW fo
r bot
h A
C a
nd D
C d
rives
. B
eing
pas
sive
an
d lin
ear,
they
do
not c
ause
EM
I em
issi
ons.
Cos
t-effe
ctiv
enes
s ca
lcul
atio
ns m
ay
show
that
it c
osts
less
to a
llow
all
the
PD
Ss
on a
site
or i
n a
vess
el to
em
it th
eir h
arm
onic
s, a
nd to
cle
an
them
up
with
a s
ingl
e fi l
ter (
pass
ive
or
activ
e) s
o th
at th
ey d
o no
t cau
se to
o m
uch
dist
ortio
n of
the
mai
ns v
olta
ge
wav
efor
m.
Thes
e an
d ot
her “
inst
alla
tion
leve
l” te
chni
ques
are
dis
cuss
ed in
pag
es
42-6
2 of
[29]
, and
[35]
.
4.4.
11.
Mai
ns v
olta
ge
fl uct
uatio
ns[1
] set
s lim
its fo
r the
gen
erat
ion
of
mai
ns v
olta
ge fl
uctu
atio
ns, f
or w
hich
th
ere
are
only
a fe
w in
stal
latio
n-le
vel m
itiga
tion
tech
niqu
es, s
uch
as
Dyn
amic
Vol
tage
Res
tore
rs (D
VR
s)
see
page
s 36
-49
of [3
0].
At t
he le
vel o
f the
mot
or d
rive,
the
maj
or b
enefi
t co
mes
from
usi
ng “s
oft-
star
ting”
, esp
ecia
lly fo
r AC
mot
ors
beca
use
they
can
dra
w v
ery
larg
e m
agne
tisin
g cu
rren
ts w
hen
switc
hed
Dire
ct-O
n-Li
ne (D
OL)
nea
r the
ze
ro-c
ross
ings
of t
he m
ains
vol
tage
. U
sing
VFD
s so
lves
this
pro
blem
au
tom
atic
ally.
Whe
re h
igh-
pow
ered
driv
es h
ave
a ra
pidl
y fl u
ctua
ting
load
, the
fl uc
tuat
ing
Pha
se-s
hifti
ng m
ains
tran
sfor
mer
s ca
n be
use
d to
cre
ate
six-
phas
e (o
ften
calle
d 12
-pul
se) r
ectifi
ers
, w
hich
has
the
effe
ct o
f cau
sing
the
5th
and
7th h
arm
onic
s to
be
subs
tant
ially
ca
ncel
led
out i
n th
e re
ctifi
er’s
circ
uits
, so
that
its
fi rst
sig
nifi c
ant m
ains
ha
rmon
ic is
the
13th. I
ncre
asin
g m
ultip
les
of th
ree
phas
es (o
r six
pu
lses
) atte
nuat
es e
ven
high
er-o
rder
ha
rmon
ics,
but
the
spec
ifi ca
tion
on
the
purit
y of
the
mai
ns s
uppl
y’s
sine
w
avef
orm
and
equ
ipm
ent a
nd p
hase
sh
ift tr
ansf
orm
er q
ualit
y (in
tern
al
imba
lanc
e to
lera
nce
leve
ls) m
ust
incr
ease
with
the
num
ber o
f pha
ses
for t
his
to b
e ef
fect
ive.
How
ever
, us
ing
larg
e or
mul
tiple
-pha
se-s
hift
trans
form
ers,
as
is ty
pica
l of o
il pr
oduc
tion
plat
form
s, c
an s
till r
educ
e th
is e
xces
sive
vol
tage
dis
torti
on,
espe
cial
ly a
t hig
her o
rder
whe
re th
ey
are
both
mos
t pro
blem
atic
and
diffi
cul
t to
trea
t.
Shi
ps a
nd o
ther
ves
sels
ofte
n ha
ve
very
dis
torte
d m
ains
sup
plie
s be
caus
e th
eir e
lect
ricity
gen
erat
ors
have
muc
h hi
gher
(abo
ut 3
tim
es) t
he s
ourc
e im
peda
nce
of a
land
lubb
er’s
HV
tra
nsfo
rmer
of t
he s
ame
VA ra
ting,
and
al
so b
ecau
se o
f the
incr
ease
d us
e of
po
wer
ful V
FDs
in “e
lect
ric th
rust
ers”
an
d ev
en e
lect
rical
pro
puls
ion.
For
th
is re
ason
, 6-p
hase
and
hig
her
(12-
puls
e an
d hi
gher
) rec
tifi e
rs a
re
ofte
n un
suita
ble
for s
hips
, bec
ause
th
ey re
ly o
n lo
w-d
isto
rtion
mai
ns fo
r th
eir h
arm
onic
impr
ovem
ents
. So
ship
s an
d ve
ssel
s of
ten
use
spec
ial
harm
onic
sup
pres
sion
tech
niqu
es th
at
are
not c
omm
only
use
d in
land
-bas
ed
inst
alla
tions
, see
[35]
for d
etai
ls.
A re
ason
ably
new
des
ign
tech
niqu
e,
at th
e tim
e of
writ
ing,
is th
e “a
ctiv
e fro
nt e
nd” (
AFE
), w
hich
use
s IG
BTs
in
stea
d of
pla
in o
ld re
ctifi
ers.
The
se
are
switc
hed
at a
hig
h ra
te, j
ust l
ike
a ch
oppe
r tha
t driv
es P
WM
into
a
mot
or, b
ut c
ontro
l sof
twar
e ar
rang
es
the
sequ
enci
ng a
nd ti
min
g so
that
, af
ter p
assi
ng th
roug
h a
serie
s in
duct
or
to a
vera
ge o
ut th
e P
WM
, the
resu
lt is
a
rect
ifi er
that
app
ears
to th
e m
ains
su
pply
as
a su
bsta
ntia
lly li
near
(i.e
. re
sist
ive)
load
, whi
ch a
s a
dire
ct
cons
eque
nce
is c
laim
ed to
ach
ieve
lo
w e
mis
sion
s of
mai
ns h
arm
onic
s (<
5% I th
d).
How
ever
, AFE
s ac
hiev
e th
is a
t the
co
st o
f sig
nifi c
ant h
arm
onic
cur
rent
s in
the
supp
ly a
t the
sw
itchi
ng
frequ
ency
of t
he A
FE b
ridge
, hig
her
EM
I em
issi
ons
betw
een
10kH
z an
d 10
0kH
z, a
nd o
ther
a n
umbe
r of o
ther
is
sues
. A
FE re
ctifi
ers,
bei
ng s
erie
s de
vice
s, h
ave
to b
e di
men
sion
ed
for t
he to
tal l
oad.
Thi
s, o
f cou
rse,
is
a m
atte
r of d
rive
sele
ctio
n, a
nd is
no
t oth
erw
ise
unde
r the
con
trol o
f a
syst
em in
tegr
ator
or i
nsta
ller.
Filte
ring
was
men
tione
d ea
rlier
as
a m
eans
of s
uppr
essi
ng m
ains
ha
rmon
ics,
usi
ng p
assi
ve fi
lters
suc
h as
reso
nant
trap
s. A
noth
er te
chni
que
is th
e so
-cal
led
“act
ive
fi lte
r”, w
hich
5253
nece
ssar
y) e
ither
fi lte
red
or s
cree
ned.
W
hen
fi lte
ring
tech
niqu
es a
re u
sed,
fi l
ters
may
be
need
ed a
t bot
h en
ds,
beca
use
the
DC
-Lin
k ca
rrie
s no
ises
ge
nera
ted
by b
oth
the
rect
ifi er
and
the
chop
per.
4.4.
14.
Neu
tral
shi
ft ca
n st
ress
mot
or in
sula
tion
Sec
tion
4-12
of [
36] d
iscu
sses
the
prob
lem
s of
incr
easi
ng n
eutra
l-ea
rth/g
roun
d vo
ltage
cau
sed
by
VS
Ds
with
Wye
-con
nect
ed in
puts
. It
also
dis
cuss
es s
olut
ions
that
can
be
used
whe
n a
Del
ta c
onne
cted
mai
ns
inpu
t can
not b
e us
ed. T
hese
incl
ude
usin
g an
isol
atio
n tra
nsfo
rmer
at t
he
mai
ns in
put a
nd fl
oatin
g th
e ne
utra
l co
nnec
tion
to th
e V
SD
.
4.5.
Ins
ulat
ed N
eutr
al,
“fl o
atin
g” m
ains
pow
er
syst
ems
Shi
ps a
nd o
ther
ves
sels
gen
eral
ly u
se
mai
ns s
uppl
ies
that
do
not h
ave
the
neut
ral o
f the
ir m
ains
pow
er s
uppl
y di
rect
ly b
onde
d to
thei
r ear
th/g
roun
d st
ruct
ure
[35]
, and
som
e la
nd-b
ased
in
stal
latio
ns a
lso
use
this
pra
ctic
e.
This
is k
now
n as
an
IT p
ower
net
wor
k (n
othi
ng to
do
with
Info
rmat
ion
Tech
nolo
gy!).
EN
/IEC
618
00-3
[1] a
ssum
es
(D.1
.2.2
and
D.2
.2) t
hat fi
lter
ing
is
an u
nsui
tabl
e te
chni
que
whe
re th
e m
ains
pow
er n
etw
ork
is is
olat
ed
from
gro
und,
and
say
s th
at in
su
ch s
ituat
ions
the
only
miti
gatio
n po
ssib
le is
to e
nsur
e th
at a
ll th
e ot
her
equi
pmen
t on
the
site
is im
mun
e en
ough
to th
e no
ise
emitt
ed b
y th
e P
DS
. But
this
igno
res
the
poss
ibili
ty o
f in
terfe
renc
e w
ith e
quip
men
t off-
site
, an
d w
ith ra
dio
rece
iver
s, s
o is
not
a
com
plet
e so
lutio
n.
How
ever
, if fi
lter
s ar
e fi t
ted
to
indi
vidu
al B
DM
s as
reco
mm
ende
d in
this
Gui
de, a
ll th
at is
nec
essa
ry
is to
“fl o
at” t
he c
hass
is, f
ram
e or
en
clos
ure
of th
e B
DM
. Sin
ce th
e m
ains
and
out
put fi
lter
s (if
use
d) w
ill
be R
F-bo
nded
dire
ctly
to th
e B
DM
’s
chas
sis,
fram
e or
enc
losu
re th
ey w
ill
not i
ncre
ase
the
leak
age
curr
ent i
nto
the
earth
/gro
und.
Of c
ours
e, th
is w
ill
mea
n pr
otec
ting
the
BD
M fr
om b
eing
to
uche
d, to
pre
vent
per
sonn
el fr
om
suffe
ring
elec
tric
shoc
ks if
ther
e is
a
phas
e-to
-ear
th/g
roun
d fa
ult i
n th
e sy
stem
.
Whe
n us
ing
cabl
e sc
reen
s an
d/or
ar
mou
r ins
tead
of o
utpu
t fi lt
ers,
a
capa
citiv
e R
F-bo
nd c
ould
be
used
at
one
end
of th
e m
otor
cab
le, e
ither
at
the
BD
M o
r in
the
mot
or’s
term
inal
bo
x. T
his
will
not
be
as e
ffect
ive
as
a pr
oper
360
° R
F-bo
nd, b
ut m
ay b
e go
od e
noug
h if
thei
r lea
d le
ngth
s ar
e ke
pt v
ery
shor
t. Fo
r saf
ety,
suc
h sc
reen
-bon
ding
cap
acito
rs s
houl
d be
saf
ety-
rate
d fo
r the
full
phas
e-to
-ph
ase
volta
ge, a
nd o
f cou
rse
thei
r ef
fect
on
the
amou
nt o
f ear
th/g
roun
d
mot
or c
urre
nts
can
also
giv
e ris
e to
si
gnifi
cant
mai
ns v
olta
ge fl
uctu
atio
ns.
This
may
be
able
to b
e cu
red
by
addi
ng in
ertia
l ene
rgy
stor
age
(e.g
. a
larg
er fl
ywhe
el) o
r by
inst
allin
g a
DV
R
with
an
adeq
uate
ratin
g, s
ee 5
.3.9
on
page
48
of [3
0].
4.4.
12.
Rad
iate
d EM
di
stur
banc
es –
low
freq
uenc
y H
-fi el
dsTh
ese
are
supp
ress
ed b
y th
e fi l
terin
g an
d ca
ble
scre
enin
g m
etho
ds
disc
usse
d ea
rlier
, and
by
ensu
ring
that
all
cond
ucto
rs c
arry
ing
DM
loop
s ar
e in
clo
se p
roxi
mity
, pre
fera
bly
twis
ted
toge
ther
, alo
ng th
eir e
ntire
ro
ute,
see
sec
tion
4.4
of [1
9].
Whe
re c
able
s ca
rry
curr
ents
that
are
to
o la
rge
to p
erm
it th
em to
be
twis
ted
or p
lace
d cl
ose
toge
ther
, bec
ause
of
the
phys
ical
dam
age
that
wou
ld
occu
r to
thei
r ins
ulat
ion
due
to th
e el
ectro
-mot
ive
forc
es a
ctin
g on
thei
r co
nduc
tors
, it m
ay b
e po
ssib
le to
ar
rang
e fo
r ext
erna
l shi
eldi
ng a
roun
d th
e bu
ndle
of c
ondu
ctor
s to
pro
tect
ne
arby
equ
ipm
ent f
rom
the
mag
netic
fi e
lds
(see
5.1
2 in
[19]
).
But
shi
eldi
ng c
an b
e ve
ry c
ostly
, es
peci
ally
in th
e ca
se o
f ver
y lo
w
frequ
enci
es –
say
bel
ow 1
kHz
– w
here
it c
an a
lso
be v
ery
diffi
cult
to d
o at
all.
Whe
re p
robl
ems
aris
e w
ith lo
w-
frequ
ency
mag
netic
fi el
d em
issi
ons,
fo
r ins
tanc
e in
a ±
8kA
DC
driv
e I s
aw
in a
ste
el m
ill, o
ften
the
only
sol
utio
ns
are
eith
er to
mak
e su
re th
at s
ensi
tive
equi
pmen
t is
loca
ted
far e
noug
h aw
ay
not t
o be
effe
cted
, use
equ
ipm
ent
that
is n
ot s
ensi
tive
(e.g
. use
pla
sma
or L
CD
com
pute
r scr
eens
inst
ead
of
cath
ode
ray
tube
(CR
T) ty
pes)
, or fi
t lo
calis
ed s
cree
ning
to th
e af
fect
ed
item
s of
equ
ipm
ent.
Scr
eeni
ng fo
r ver
y lo
w fr
eque
ncie
s ca
n be
pas
sive
(e.g
. usi
ng
MuM
etal
TM);
or a
ctiv
e, in
whi
ch m
etal
fra
mew
orks
are
driv
en w
ith c
urre
nts
to c
reat
e m
agne
tic fi
elds
that
“can
cel
out”
the
loca
l am
bien
t mag
netic
fi el
d.
Whe
re th
ere
are
pow
erfu
l cur
rent
s th
ere
is a
lway
s th
e po
ssib
ility
that
hu
man
exp
osur
e to
the
resu
lting
m
agne
tic fi
elds
cou
ld b
e to
o hi
gh, s
ee
[10]
and
[11]
for l
imits
, and
met
hods
fo
r tes
ting
and
calc
ulat
ion.
4.4.
13.
Emis
sion
s fr
om th
e D
C-L
ink
DC
-Lin
k co
nduc
tors
can
car
ry a
s m
uch
nois
e as
the
outp
ut c
able
s.
Figu
re 1
4 sh
ows
that
ther
e is
som
e st
ray
capa
cita
nce
to e
arth
/gro
und
from
the
DC
-Lin
k co
nduc
tors
, so
the
nois
e vo
ltage
s an
d cu
rren
ts o
n th
e D
C-L
ink
can
coup
le n
oise
into
oth
er
equi
pmen
t and
radi
o re
ceiv
ers
by
indu
ctio
n or
radi
atio
n.
The
DC
-Lin
k sh
ould
ther
efor
e be
tre
ated
like
a m
otor
cab
le: m
ade
as s
hort
as p
ract
icab
le, a
nd th
en (i
f
5455
5.1.
Pow
er q
ualit
y is
sues
Sec
tion
5 of
[30]
is th
e m
ost r
elev
ant
refe
renc
e fo
r ins
talla
tion-
leve
l m
etho
ds fo
r dea
ling
with
poo
r pow
er
qual
ity, a
nd 4
.2 o
f [19
] will
als
o be
us
eful
.
Par
t 6.5
of [
21] d
escr
ibes
a n
umbe
r of
way
s of
des
igni
ng e
quip
men
t to
impr
ove
its im
mun
ity to
pow
er q
ualit
y is
sues
, and
som
e of
thos
e te
chni
ques
ca
n al
so b
e ap
plie
d “s
tand
-alo
ne” t
o a
PD
S, s
yste
m o
r ins
talla
tion.
And
the
tech
niqu
es fo
r dea
ling
with
co
mm
utat
ion
notc
hing
and
oth
er
low
-freq
uenc
y em
issi
ons
such
as
harm
onic
s an
d in
terh
arm
onic
s de
scrib
ed in
sec
tion
4 ab
ove,
may
al
so b
e ab
le to
be
used
to im
prov
e im
mun
ity to
thos
e el
ectro
mag
netic
di
stur
banc
es.
5.2.
Mag
netic
fi el
ds,
cond
ucte
d/ra
diat
ed
dist
urba
nces
, fas
t tra
nsie
nts
Whe
re a
PD
S h
as p
robl
ems
com
plyi
ng w
ith th
e te
sts
for i
mm
unity
to
mag
netic
fi el
ds; c
ondu
cted
co
ntin
uous
EM
dis
turb
ance
s (1
50kH
z to
80M
Hz)
; fas
t tra
nsie
nts,
an
d/or
radi
ated
con
tinuo
us E
M
dist
urba
nces
(80M
Hz
to 1
GH
z)
– th
e us
ual s
olut
ions
are
to u
se th
e fi l
terin
g an
d sc
reen
ing
tech
niqu
es
disc
usse
d in
sec
tion
4 ab
ove
for
supp
ress
ing
emis
sion
s of
low
and
high
freq
uenc
ies.
A te
chni
que
that
atte
nuat
es a
n eq
uipm
ent’s
em
issi
ons
of a
par
ticul
ar
elec
trom
agne
tic d
istu
rban
ce,
gene
rally
pro
vide
s a
sim
ilar l
evel
of
atte
nuat
ion
whe
n pr
otec
ting
equi
pmen
t fro
m in
terfe
renc
e by
that
sa
me
type
of d
istu
rban
ce.
5.3.
Sur
ge tr
ansi
ents
Ser
ies
indu
ctor
s us
ed fo
r sup
pres
sing
em
issi
ons
of h
arm
onic
s or
co
mm
utat
ion
notc
hes
also
hel
p in
crea
se a
driv
e’s
imm
unity
to s
urge
tra
nsie
nts.
Oth
er te
chni
ques
are
ga
lvan
ic is
olat
ion
and
surg
e pr
otec
tion
devi
ces
(SP
Ds)
, whi
ch a
re d
iscu
ssed
in
sec
tions
4.3
and
5.1
3 of
[19]
, re
spec
tivel
y.
Thes
e te
chni
ques
can
be
used
in
divi
dual
ly, o
r tog
ethe
r in
any
com
bina
tion.
5.4.
Ele
ctro
stat
ic d
isch
arge
(E
SD)
ES
D te
chni
ques
for e
quip
men
t are
co
vere
d in
par
t 6.1
of [
21],
and
they
ca
n be
app
lied
to a
com
plet
e B
DM
by
enc
losi
ng it
in e
ither
a p
last
ic
encl
osur
e (to
pre
vent
ES
D fr
om
occu
rrin
g at
all)
or i
n a
shie
lded
en
clos
ure
(to d
iver
t ES
D d
istu
rban
ces
away
from
the
BD
M’s
ele
ctro
nics
w
ithin
).
Pla
stic
enc
losu
res
do n
ot p
rote
ct
leak
age
curr
ent m
ust b
e ta
ken
into
ac
coun
t.
Ano
ther
tech
niqu
e fo
r red
ucin
g th
e ea
rth/g
roun
d le
akag
e of
fi lte
rs a
nd
cabl
e sc
reen
/arm
our b
onds
, is
to fi
t a
co-lo
cate
d is
olat
ing
trans
form
er
to th
e P
DS
so
that
it c
an b
e bo
nded
di
rect
ly to
the
earth
/gro
und
with
out
com
prom
isin
g th
e re
st o
f the
sys
tem
. O
f cou
rse,
if th
e P
DS
is p
ower
ed fr
om
a de
dica
ted
and
co-lo
cate
d st
ep-
dow
n is
olat
ing
mai
ns tr
ansf
orm
er,
a se
para
te is
olat
ing
trans
form
er is
no
t req
uire
d –
its E
MI s
uppr
essi
on
func
tion
is p
rovi
ded
by th
e st
ep-d
own
trans
form
er.
5. I
mm
unity
As
wel
l as
deal
ing
with
em
issi
ons,
E
N/IE
C 6
1800
-3 [1
] spe
cifi e
s te
st
met
hods
and
test
leve
ls fo
r im
mun
ity.
The
issu
es it
is c
once
rned
with
are
:
Pow
er q
ualit
y is
sues
, inc
ludi
ng:
Dis
torte
d m
ains
sup
plie
s (in
clud
ing
harm
onic
dis
torti
on
and
com
mut
atio
n no
tche
s)
Sup
ply
volta
ge d
evia
tions
, va
riatio
ns, c
hang
es, fl
uct
uatio
ns,
dips
, dro
pout
s an
d sh
ort
inte
rrup
tions
Thre
e-ph
ase
volta
ge u
nbal
ance
Mai
ns fr
eque
ncy
varia
tions
Mag
netic
fi el
dsC
ondu
cted
con
tinuo
us E
M
dist
urba
nces
(150
kHz
to 8
0MH
z)Fa
st tr
ansi
ents
Rad
iate
d co
ntin
uous
EM
di
stur
banc
es (8
0MH
z to
1G
Hz)
Sur
ge tr
ansi
ents
Ele
ctro
stat
ic d
isch
arge
Mos
t of t
hese
are
bes
t dea
lt w
ith
by th
e de
sign
of t
he e
quip
men
t, as
de
scrib
ed in
[21]
and
[22]
, and
so
not
in th
e sc
ope
of th
is G
uide
.
To d
iscu
ss w
hat c
an b
e do
ne to
im
prov
e th
e im
mun
ity o
f a P
DS
by
usin
g in
stal
latio
n te
chni
ques
, the
im
mun
ity p
robl
ems
can
be b
roke
n do
wn
into
four
gro
ups,
see
bel
ow.
5657
7. R
efer
ence
san
d fu
rthe
r rea
ding
[1]
EN
618
00-3
:200
4, “A
djus
tabl
e S
peed
Ele
ctric
al P
ower
Driv
e S
yste
ms
– P
art 3
: EM
C
requ
irem
ents
and
spe
cifi c
test
m
etho
ds”.
Iden
tical
to IE
C
6180
0-3:
2004
.
[2]
Eur
opea
n U
nion
Dire
ctiv
e 20
04/1
08/E
C (a
s am
ende
d) o
n E
lect
rom
agne
tic C
ompa
tibili
ty
(2nd
Edi
tion)
in E
nglis
h: h
ttp://
eur-
lex.
euro
pa.e
u/Le
xUriS
erv/
site
/en/
oj/2
004/
l_39
0/l_
3902
0041
231e
n002
4003
7.pd
f
– in
any
EU
lang
uage
: http
://ec
.eur
opa.
eu/e
nter
pris
e/el
ectr_
equi
pmen
t/em
c/di
rect
iv/d
ir200
4_10
8.ht
m
The
Dire
ctiv
e’s
offi c
ial
EU
hom
epag
e in
clud
es a
do
wnl
oada
ble
vers
ion
of th
e cu
rren
t EM
C D
irect
ive
and
its
succ
esso
r; a
tabl
e of
all
the
EN
sta
ndar
ds li
sted
und
er
the
Dire
ctiv
e; a
gui
danc
e do
cum
ent o
n ho
w to
app
ly th
e D
irect
ive;
list
s of
app
oint
ed E
MC
C
ompe
tent
Bod
ies;
etc
., al
l at
: ht
tp://
euro
pa.e
u.in
t/com
m/
ente
rpris
e/el
ectr_
equi
pmen
t/em
c/in
dex.
htm
.
[3]
Kei
th A
rmst
rong
, “C
ompl
ying
w
ith th
e E
MC
Dire
ctiv
e (2
004/
108/
EC
), S
econ
d E
ditio
n”,
Con
form
ity, M
arch
200
8, p
ages
12
-22,
http
://w
ww
.con
form
ity.
com
/PD
Fs/0
803/
0803
_F1.
pdf.
Als
o pu
blis
hed
in a
slig
htly
am
ende
d fo
rm in
Con
form
ity’s
20
09 A
nnua
l Ref
eren
ce G
uide
.
[4]
Sev
ente
en E
MC
Gui
des
on E
M
phen
omen
a, le
gal c
ompl
ianc
e an
d E
MC
test
ing
have
bee
n w
ritte
n by
Kei
th A
rmst
rong
an
d pu
blis
hed
by R
EO
(UK
) Lt
d. T
hey
are
very
read
able
an
d pr
actic
al, a
nd c
an b
e do
wnl
oade
d fro
m w
ww
.reo.
co.u
k/kn
owle
dgeb
ase.
They
are
als
o av
aila
ble
from
R
EO
(UK
) Ltd
and
Che
rry
Clo
ugh
Con
sulta
nts
as a
CD
-R
OM
that
con
tain
s al
l 17
of th
em
plus
two
othe
r RE
O E
MC
Gui
des
and
a gr
eat d
eal o
f oth
er u
sefu
l in
form
atio
n on
EM
C.
[5]
“On-
Site
EM
C T
est M
etho
ds”,
Kei
th A
rmst
rong
, EM
C T
est L
abs
Ass
ocia
tion
(ww
w.e
mct
la.c
o.uk
) Te
chni
cal G
uida
nce
Not
e N
o.
TGN
49,
als
o av
aila
ble
from
the
“Pub
licat
ions
and
Dow
nloa
ds”
page
s at
ww
w.c
herr
yclo
ugh.
com
.
[6]
The
EC
’s o
ffi ci
al G
uide
to
2004
/108
/EC
can
be
dow
nloa
ded
from
: http
://ec
.eur
opa.
eu/
ente
rpris
e/el
ectr_
equi
pmen
t/em
c/di
rect
iv/d
ir200
4_10
8.ht
m#g
uide
from
the
radi
ated
fi el
ds o
f a n
earb
y di
scha
rge,
so
it m
ay tu
rn o
ut th
at a
sh
ield
ing
solu
tion
is b
ette
r. Th
is is
th
en ju
st a
mat
ter o
f app
lyin
g th
e sh
ield
ing
tech
niqu
es b
riefl y
intro
duce
d in
4.4
.5 a
bove
, usu
ally
aim
ing
for t
he
uppe
r fre
quen
cy to
be
cont
rolle
d to
be
at le
ast 1
GH
z, id
eally
3G
Hz.
To s
uppr
ess
ES
D w
ithin
an
inst
alla
tion
mea
ns p
reve
ntin
g it
from
hap
peni
ng
by u
sing
sta
tic c
ontro
l mea
sure
s:
diss
ipat
ive
fl oor
ing
and
othe
r sur
face
s,
diss
ipat
ive
clot
hing
, ion
isin
g bl
ower
s,
cont
rol o
f rel
ativ
e hu
mid
ity e
tc.,
all
very
fam
iliar
to a
nyon
e w
ho h
as
wor
ked
in s
emic
ondu
ctor
man
ufac
ture
or
ligh
t ele
ctro
nic
asse
mbl
y.
6. E
MC
sup
pres
sion
pr
oduc
ts fr
om R
EOFi
gure
28
show
s th
e ra
nge
of p
rodu
cts
that
RE
O p
rovi
des
for s
uppr
essi
ng
and/
or p
rote
ctin
g m
otor
driv
es.
L1 L2 L3
M 3
Inpu
t Filt
erLi
ne In
duct
or
Com
bine
d Fi
lter I
nduc
tor
DC
Lin
k C
hoke
Bra
king
Res
isto
r
dV/d
tFi
lter
Mot
orIn
duct
or
Sin
usoi
dal
Filte
r
DC
Con
verte
rP
WM
Inve
rter
Out
put F
ilter
Figu
re 2
8: R
EO’s
mot
or d
rive
prod
ucts
5859
Mor
e “B
anan
a S
kins
” are
pu
blis
hed
6 tim
es a
yea
r in
“The
E
MC
Jou
rnal
”, av
aila
ble
free
at
ww
w.th
eem
cjou
rnal
.com
or w
ww
.co
mpl
ianc
e-cl
ub.c
om.
[16]
IEC
TS
610
00-1
-2, b
asic
saf
ety
publ
icat
ion,
dra
ft se
cond
edi
tion,
Ja
nuar
y 20
08, “
Ele
ctro
mag
netic
C
ompa
tibili
ty (E
MC
) – P
art 1
-2:
Gen
eral
– M
etho
dolo
gy fo
r the
ac
hiev
emen
t of t
he fu
nctio
nal
safe
ty o
f ele
ctric
al a
nd e
lect
roni
c eq
uipm
ent w
ith re
gard
to
elec
trom
agne
tic p
heno
men
a.”
[17]
The
IET,
“Gui
de o
n E
MC
for
Func
tiona
l Saf
ety”
, Aug
ust 2
008,
IS
BN
978
-0-9
5551
18-2
-0
Cos
t £27
plu
s p&
p fro
m h
ttp://
ww
w.e
mca
cade
my.
org/
book
s.as
p or
free
dow
nloa
d fro
m w
ww
.th
eiet
.org
/fact
fi les
/em
c/in
dex.
cfm
.
[18]
The
“Mac
hine
ry S
afet
y D
irect
ive”
: “D
irect
ive
98/3
7/E
C o
f the
E
urop
ean
Par
liam
ent a
nd o
f th
e C
ounc
il of
22
June
199
8 on
th
e ap
prox
imat
ion
of th
e la
ws
of
the
Mem
ber S
tate
s re
latin
g to
m
achi
nery
”
The
new
Mac
hine
ry S
afet
y D
irect
ive:
“Dire
ctiv
e 20
06/4
2/E
C
of th
e E
urop
ean
Par
liam
ent a
nd
of th
e C
ounc
il of
17
May
200
6 on
mac
hine
ry, a
nd a
men
ding
D
irect
ive
95/1
6/E
C (r
ecas
t)”
[19]
RE
O G
uide
on
“Goo
d E
MC
E
ngin
eerin
g P
ract
ices
in th
e D
esig
n an
d C
onst
ruct
ion
of F
ixed
Inst
alla
tions
”, fre
e do
wnl
oad
from
: ww
w.re
o.co
.uk/
know
ledg
ebas
e
[20]
RE
O G
uide
on
“Goo
d E
MC
E
ngin
eerin
g P
ract
ices
in th
e D
esig
n an
d C
onst
ruct
ion
of In
dust
rial C
abin
ets”
, av
aila
ble
from
ww
w.re
o.co
.uk/
know
ledg
ebas
e
[21]
Kei
th A
rmst
rong
, “D
esig
n Te
chni
ques
for E
MC
” in
six
parts
, The
EM
C J
ourn
al, I
ssue
62
thro
ugh
Issu
e 77
(Jan
uary
20
06 th
roug
h Ju
ly 2
008)
, ww
w.
thee
mcj
ourn
al.c
om, (
sear
ch b
y “K
eith
Arm
stro
ng”)
[22]
Kei
th A
rmst
rong
, “E
MC
for
Prin
ted
Circ
uit B
oard
s –
Bas
ic
and
Adv
ance
d D
esig
n an
d La
yout
Tec
hniq
ues”
, Nut
woo
d/A
rmst
rong
, Feb
ruar
y 20
07, £
47
plus
p&
p.
Per
fect
bou
nd (w
ith ti
tled
spin
e):
ISB
N 9
78-0
-955
5118
-1-3
Spi
ral b
ound
(lay
s fl a
t):
ISB
N 9
78-0
-955
5118
-0-6
Ord
er v
ia h
ttp://
ww
w.
emca
cade
my.
org/
book
s.as
p
[23]
Kei
th A
rmst
rong
, “B
OM
Cos
t and
P
rofi t
abili
ty”,
The
EM
C J
ourn
al,
Issu
e 82
, May
200
9, p
ages
32-
34, w
ww
.thee
mec
jour
nal.c
om
[7]
The
EM
C R
egul
atio
ns 2
006,
U
nite
d K
ingd
om S
tatu
tory
In
stru
men
t 200
6 N
o. 3
418:
http
://w
ww
.ops
i.gov
.uk/
si/s
i200
6/uk
si_
2006
3418
_en.
pdf,
impl
emen
ting
2004
/108
/EC
in U
K la
w.
[8]
The
offi
cial
gui
de to
the
UK
’s
2006
EM
C R
egul
atio
ns is
pos
ted
unde
r “R
elat
ed D
ocum
ents
” at
: http
://w
ww
.ber
r.gov
.uk/
dius
/in
nova
tion/
regu
latio
ns/e
cdire
ct/
page
1246
9.ht
ml
[9]
The
cons
olid
ated
ver
sion
of t
he
Low
Vol
tage
Dire
ctiv
e, 2
006/
95/
EC
, rep
lace
s 73
/23/
EE
C a
nd it
s am
endm
ent b
y 93
/68/
EE
C, h
ttp://
euro
pa.e
u.in
t/com
m/e
nter
pris
e/el
ectr_
equi
pmen
t/lv/
inde
x.ht
m
[10]
199
9/51
9/E
C, “
Cou
ncil
reco
mm
enda
tion
1999
/519
/EC
on
the
limita
tion
of e
xpos
ure
of th
e ge
nera
l pub
lic to
el
ectro
mag
netic
fi el
ds (0
Hz
to 3
00 G
Hz)
”, fro
m: h
ttp://
ec.e
urop
a.eu
/ent
erpr
ise/
elec
tr_eq
uipm
ent/l
v/em
f.htm
[11]
EN
623
11:2
008,
“Gen
eric
st
anda
rd to
dem
onst
rate
th
e co
mpl
ianc
e of
ele
ctro
nic
and
elec
trica
l app
arat
us
with
the
basi
c re
stric
tions
re
late
d to
hum
an e
xpos
ure
to
elec
trom
agne
tic fi
elds
(0 H
z -
300
GH
z)” (
a m
odifi
ed v
ersi
on o
f IE
C 6
2311
:200
7, it
repl
aces
EN
50
392:
2004
).
[12]
200
4/40
/EC
, “O
n th
e m
inim
um
heal
th a
nd s
afet
y re
quire
men
ts
rega
rdin
g th
e ex
posu
re o
f w
orke
rs to
the
risks
aris
ing
from
ph
ysic
al a
gent
s (e
lect
rom
agne
tic
fi eld
s) (1
8th
indi
vidu
al D
irect
ive
with
in th
e m
eani
ng o
f Arti
cle
16(1
) of D
irect
ive
89/3
91/E
EC
)”,
date
d 29
Apr
il 20
04. F
rom
: ht
tp://
ww
w.h
se.g
ov.u
k/ra
diat
ion/
noni
onis
ing/
l184
emf.p
df
[13]
EN
/IEC
618
00-5
-2, “
Adj
usta
ble
spee
d el
ectri
cal p
ower
driv
e sy
stem
s –
Par
t 5-2
: Saf
ety
requ
irem
ents
– F
unct
iona
l”
[14]
IEC
615
08: “
Func
tiona
l Saf
ety
of E
lect
rical
, Ele
ctro
nic
and
Pro
gram
mab
le E
lect
roni
c S
yste
ms”
(sev
en p
arts
)
[15]
The
Firs
t 500
“Ban
ana
Ski
ns”,
Nut
woo
d U
K, 2
007,
500
repo
rts
and
anec
dote
s co
ncer
ning
el
ectro
mag
netic
inte
rfere
nce
(EM
I). R
ead
it at
ww
w.
thee
mcj
ourn
al.c
om, o
r buy
fro
m p
am@
nutw
ood.
eu.c
om
(app
roxi
mat
ely
£10)
or v
ia h
ttp://
ww
w.e
mca
cade
my.
org/
book
s.as
p.
Num
bers
: 1, 1
8, 5
0, 1
01, 1
62,
168,
233
, 274
, 278
, 279
, 282
, 32
4, 4
33, 4
38, 4
55, 4
69, 4
83
conc
ern
inci
dent
s as
soci
ated
w
ith s
witc
h-m
ode
pow
er
conv
ersi
on, i
nclu
ding
var
iabl
e sp
eed
mot
or d
rives
.
6061
Inte
rnat
iona
l EM
C S
ympo
sium
, A
ustin
Tex
as, U
SA
, 17-
22 A
ugus
t 20
09, I
SB
N: 9
78-1
-424
4-42
85-0
EN
and
IEC
sta
ndar
ds m
ay b
e pu
rcha
sed
from
Brit
ish
Sta
ndar
ds
Inst
itutio
n (B
SI)
at: o
rder
s@bs
i-glo
bal.
com
. To
enqu
ire a
bout
a p
rodu
ct o
r se
rvic
e ca
ll B
SI C
usto
mer
Ser
vice
s on
+44
(0)2
0 89
96 9
001
or e
-mai
l th
em a
t cse
rvic
es@
bsi-g
loba
l.com
. IE
C s
tand
ards
can
als
o be
pur
chas
ed
with
a c
redi
t car
d, in
Eng
lish
and
man
y ot
her l
angu
ages
, fro
m h
ttp://
web
stor
e@ie
c.ch
.
[24]
Kei
th A
rmst
rong
, “G
ettin
g W
hat
You
Wan
t”, T
he E
MC
Jou
rnal
, Is
sue
77, J
uly
2008
, pag
es 1
9-21
, ww
w.th
eem
cjou
rnal
.com
[25]
Kei
th A
rmst
rong
, “A
bsen
ce o
f P
roof
is N
ot P
roof
of A
bsen
ce
(and
the
“pro
ven
in u
se” f
alla
cy)”
, Th
e E
MC
Jou
rnal
, Iss
ue 7
8,
Sep
tem
ber 2
008,
pag
es 1
6-20
, w
ww
.thee
mcj
ourn
al.c
om
[26]
Tim
Will
iam
s an
d K
eith
A
rmst
rong
, “E
MC
for S
yste
ms
and
Inst
alla
tions
”, N
ewne
s,
2000
, IS
BN
: 0-7
506-
4167
-3,
ww
w.b
h.co
m/n
ewne
s, R
S
Com
pone
nts
16/N
o. 3
77-6
463,
(a
ppro
xim
atel
y £4
7, p
aper
back
)
[27]
Kei
th A
rmst
rong
, “Th
e Tr
uth
of M
urph
y’s
Law
”, Th
e E
MC
Jo
urna
l, Is
sue
79, N
ovem
ber
2008
, pag
es 1
6-18
, ww
w.
thee
mcj
ourn
al.c
om
[28]
Pul
se-W
idth
Mod
ulat
ion
(PW
M),
see:
http
://en
.wik
iped
ia.o
rg/w
iki/
Pul
se-w
idth
_mod
ulat
ion
[29]
RE
O (U
K) L
td G
uide
on
“Har
mon
ics”
, ava
ilabl
e fro
m
ww
w.re
o.co
.uk/
know
ledg
ebas
e.
[30]
RE
O G
uide
on
“Pow
er Q
ualit
y”,
avai
labl
e fro
m w
ww
.reo.
co.u
k/kn
owle
dgeb
ase.
[31]
RE
O G
uide
on
“Pow
er Q
ualit
y fo
r Var
iabl
e S
peed
Driv
es”,
free
dow
nloa
d fro
m: w
ww
.reo.
co.u
k/kn
owle
dgeb
ase
[32]
“Var
iabl
e S
peed
Driv
es –
A G
uide
to
Sup
ply
Har
mon
ics
and
Oth
er
Low
-Fre
quen
cy D
istu
rban
ces”
, E
mer
son
Indu
stria
l Aut
omat
ion,
fre
e do
wnl
oad
from
: ww
w.
cont
rolte
chni
ques
.com
/gui
des
[33]
“A G
uide
to E
lect
rom
agne
tic
Com
patib
ility
(EM
C) f
or
Varia
ble
Spe
ed D
rives
”, E
mer
son
Indu
stria
l Aut
omat
ion,
fre
e do
wnl
oad
from
: ww
w.
cont
rolte
chni
ques
.com
/gui
des
[34]
“Con
trol T
echn
ique
s D
rives
and
C
ontro
ls H
andb
ook,
2nd
Edi
tion”
, B
ill D
rury
, IE
T pu
blis
hers
, 200
9,
ISB
N 9
78-1
-849
19-0
13-8
, ww
w.
thei
et.o
rg/p
ublis
hing
/boo
ks/
pow
-en/
cont
rol-t
echn
ique
s-2n
d-ed
.cfm
[35]
Am
eric
an B
urea
u of
Shi
ppin
g,
“Gui
danc
e N
otes
on
Con
trol o
f H
arm
onic
s in
Ele
ctric
al P
ower
S
yste
ms”
, May
200
6, fr
ee
dow
nloa
d fro
m: w
ww
.eag
le.
org/
absd
ownl
oads
/get
pub.
cfm
?pub
=150
[36]
EP
RI,
“Tro
uble
-Sho
otin
g G
uide
fo
r Low
-Vol
tage
AS
D/M
otor
S
yste
ms”
, TR
-110
97, fi
nal
repo
rt N
ovem
ber 1
998,
free
dow
nloa
d:
http
://m
ydoc
s.ep
ri.co
m/d
ocs/
publ
ic/T
R-1
1109
7.pd
f
[37]
K O
Phi
pps,
P F
Kee
bler
and
R
F A
rritt
, “R
eal W
orld
AS
D
Inte
rfere
nce
Cas
e S
tudy
with
M
odel
ed S
olut
ions
”, IE
EE
200
9
Ack
now
ledg
emen
t
Man
y th
anks
to Ia
n E
vans
of H
arm
onic
Sol
utio
ns C
o.U
K, f
or re
view
ing
this
text
an
d m
akin
g m
any
very
use
ful s
ugge
stio
ns.
62 Kei
th A
rmst
rong
from
Che
rry
Clo
ugh
Con
sulta
nts
Kei
th A
rmst
rong
gra
duat
ed in
el
ectri
cal e
ngin
eerin
g w
ith a
B.S
c (H
ons.
) fro
m Im
peria
l Col
lege
Lon
don
in 1
972,
maj
orin
g in
ana
logu
e ci
rcui
t de
sign
and
ele
ctro
mag
netic
fi el
d th
eory
, with
a U
pper
Sec
ond
Cla
ss
Hon
ours
(Cum
Lau
de).
Muc
h of
his
lif
e si
nce
then
has
invo
lved
con
trolli
ng
real
-life
inte
rfere
nce
prob
lem
s in
hi
gh-te
chno
logy
pro
duct
s, s
yste
ms,
an
d in
stal
latio
ns, f
or a
var
iety
of
com
pani
es a
nd o
rgan
isat
ions
in a
ra
nge
of in
dust
ries.
Kei
th h
as b
een
a C
harte
red
Ele
ctric
al
Eng
inee
r (U
K) s
ince
197
8, a
Gro
up
1 E
urop
ean
Eng
inee
r sin
ce 1
988,
and
has
writ
ten
and
pres
ente
d a
grea
t man
y pa
pers
and
arti
cles
on
EM
C. H
e is
a p
ast c
hairm
an o
f the
IE
E’s
Pro
fess
iona
l Gro
up (E
2) o
n E
lect
rom
agne
tic C
ompa
tibili
ty, i
s a
mem
ber o
f the
IEE
E’s
EM
C S
ocie
ty,
the
EM
C T
est L
abs
Ass
ocia
tion
[59]
, th
e E
MC
Indu
strie
s A
ssoc
iatio
n (w
ww
.em
cia.
org)
, and
cha
irs th
e IE
E’s
Wor
king
Gro
up o
n ‘E
MC
and
Fu
nctio
nal S
afet
y’.
Con
tact
: Kei
th A
rmst
rong
by
emai
l at
keith
.arm
stro
ng@
cher
rycl
ough
.com
or
vis
it th
e C
herr
y C
loug
h w
ebsi
te
w
ww
.che
rryc
loug
h.co
m.