specification for oil cooling unit with casing for

lR;eso t;rs
Transformer /Converter of Three Phase Locomotives
Specification No. RDSO/2016/EL/SPEC/xxxx, Rev. ‘0’
Issued on XX/XX/2016
Prepared by Checked by Issued by
SSE/SE&AM ADE/SE&AM EDSE/SE&AM
Approved by Signature
Status of Revision
S. N. Date of Revision Page No. Revision Reasons for Revision
1. - All 0 First Issue.
2.
3.
INDEX
1 Scope
after finalization of
3 Reference Standards
4 Technical Particulars
5 Service Conditions.
7 Special construction features
TRANSFORMER /CONVERTER
1.0 Scope
1.1 This specification covers the performance requirements and tests of Oil Cooling Unit(OCU)
with Centrifugal Design Impellers for transformer/converter fitted in 25 KV AC/50 Hz 3
phase drive electric locomotives.
- Blower casing
- Mounting Base
- Blower including 3 –phase asynchronous motor
1.3 Each locomotive is equipped with 3 auxiliary converters each rated at 100 KVA. These
converters directly gets supply from a common auxiliary winding of 1000 V (corresponds to
25 KV catenary voltage) from the main transformer. The three phase output voltage of the
auxiliary convertor 1&2 feeds variable voltage and variable frequency to the oil cooler unit in
3 steps (17 HZ, 33HZ, and 50 HZ) by the control electronics which gets signal from the
temperature sensors in oil cooling unit circuit.
1.4 The vendors who were approved as per CLW specification no. CLW/ES/3/0647 Alt. E will
remain approved as per this specification also till the currency of their approval.
2.0 Terminology, symbols and units.
For the purpose of this specification, the definitions given in IS: 4894 and shall apply.
3.0 Reference Standards
In preparing this specification assistance has been taken from the following specifications.
IS: 4894 - Specification for centrifugal fans.
IS: 4729 - Measurement And Evaluation Of Vibration Of Rotating Electrical Machines
ISO-1940 - Specification for dynamic balancing.
IEC 61373 -Shock Vibration level test
4.0 Technical Particulars
The technical particulars of oil cooling unit is given under Annexure-I.
5.0 Service Conditions.
5.1 The equipment and mounting arrangement shall be of robust design for traction duty and shall
withstand satisfactorily the vibration and shocks normally encountered in service as indicated
below:
due to shock.
c) Maximum transverse acceleration 1.0g
5.1.1 The vibrations are of sine wave form and the frequency ‘f’ vibration is between 1 Hz and
50Hz. The amplitude ‘A’ expressed in millimeters is given as a function of f, by the
equations:
A= 25/f for values of f from 1 Hz to 10 Hz
A= 250/f 2 for values of f exceeding 10 Hz upto 50Hz.
5.1.2 In the direction corresponding to the longitudinal movement of the vehicle, the equipment is
subjected for 2 min to 50 Hz vibration of such a nature that the maximum acceleration is
equal to 3g (amplitude ‘A’=0.3mm).
Page 5 of 22
5.1.3 The level of harmonics in three phase electric locomotives is of the order of 50% each for
voltage & current.
Atmospheric
temperature
75 o C and
Minimum temperature: - 10 o C ( Also snow fall in certain
areas during winter season)
Reference site
ii) Humidity: 100%
Rain fall : Very heavy in certain areas.
Atmospheric
conditions
: Extremely dusty and desert terrain in certain areas. The dust
concentration in air may reach a high value of 1.6 mg/m 3 . In
many iron ore and coal mine areas, the dust concentration is
very high affecting the filter and air ventilation system
Coastal area : humid and salt laden atmosphere with maximum pH value
of 8.5, Sulphate of 7 mg per liter, maximum concentration
of chlorine 6 mg per liters and maximum conductivity of
130 micro Siemens / cm
Wind speed : High wind speed in certain areas, with wind pressure
reaching 150 kg/m 2
6.1 Drive and coupling
The fan impeller shall be directly mounted on the motor shaft. A steel/Aluminium boss of
circular shape should be cast/rolled and fixed with welding/brazing to Aluminum impeller
(centrifugal design). The drive may be by a key of adequate strength with the impeller locked
in position shall be further locked against, unscrewing in service by locking plates.
Alternatively a tapered shaft without a key but with locking arrangement by bolt and locking
plate may be used.
6.2 Direction of rotation
An arrow indication the direction of rotation shall be permanently marked on the blower
casing.
6.3 Balancing
The rotor and the blower impeller shall be dynamically balanced individually, in quality grade
G 2.5 of ISO-1940.
6.4 Vibration: The vibration level when blower is coupled with motor shall not exceed 25 micron
(peak to peak) on motor bearing and 40 micron (peak to Peak) on the blower casing.
6.5 Lifting arrangements
Suitable lifting arrangement for the blower fan and the motor separately and for the complete
unit shall be provided.
7.0 Special construction features
7.1 Special manufacturing processes: As the blowers operate for long periods at high speeds; the
end rings of the impeller blade etc. should be designed with a higher margin of safety as
compared to normal industrial designs and stress calculation for the same shall be furnished.
7.2 Casing
Casing should be of heavy duty industrial design and shall be of mild steel with minimum
thickness of 5 millimeter or Aluminium alloy of suitable thickness. It should not deform during
lifting. It should be of single side intake having Mixed flow form with axial intake direction
and radial discharge direction with centrifugal impeller flow fan. The inlet cone (if required)
shall be manufactured by spinning .The inlet cone shall not be manufacture by welding ,it shall
not be hammered to give the cone shape. Inlet cone shall be die formed. Welding shall be
avoided on shroud portion of impeller. All outside welds of the housing should be welded
continuously, The welding shall be done by the qualified welder; casing shall be designed as
per existing arrangement of centrifugal fans provided on 25 KV ac electric locos type WAP-5
& 7 /WAG-9.
7.3 The mounting arrangement of the blower on the casing shall be properly secured so as to avoid
loosening during the vibrations countered in service.
7.4 Centrifugal Impeller can be fabricated /casted. The dimension in the drawing placed as
Annexure –IX is for reference, diameter of impeller shall not be more than 710 mm.
8. Finish The fan motor, the blades and the casing shall be suitably treated to remove rust and should be
coated with an anti rust primer and finished with two coats of battle ship grey synthetic paint.
All hardware’s shall be zinc plated.
9. Inter-Changeability The motor, impeller and casing shall be interchangeable with other make such that the
performance of the oil cooling unit is kept within the limits of the standard.
10. Marking plate
Each Oil cooling unit shall have a suitable name plate having the following information
engraved/punching on it:
ii) Air delivery
iv) Rated speed.
vii) Impeller diameter.
viii) Weight of the unit.
ix) Manufacturing date and year.
x) Impeller serial number , manufacturing date & year to be punched /etched on
steel /Aluminium boss
11. Maintenance Instructions
The manufacturer shall supply detailed maintenance instructions as desired by the
purchaser.
12. Drawings
The drawings (to be asked by the purchaser) giving the overall dimensions of the oil cooling
unit shall be supplied with the tender.
13. Data
The particulars of the Oil cooling Unit set shall be furnished in the data sheet at Annexure -
III.
14. Tests
14.1 General
14.2 Type & Routine tests on Motor
The type & Routine tests on prototype Motor shall be conducted as per RDSO specification
no. E-10/3/09(Motor) with Amendment no.1, 2, 3, 4, & 5.
14.3 Tests on Oil Cooling Unit
The following are the different tests on the complete Oil Cooling Unit with casing.
a) Type Tests
v) Shock Vibration level test in line with IEC 61373.
vi) Weighment
viii) Checking of dimensions, workmanship, clearance of impeller fixing and locking
arrangement.
ix) Starting current , running current ,starting time at full load at
- 373V, 33Hz
- 415V, 50Hz to be recorded.
x) The balancing of rotor with impeller shall be done and to be witness by inspection
officials. The balancing shall conform to grade 2.5of ISO-1940.
xi) DPT on impeller welding shall be witness by Inspecting officials.
xii) Noise measurement at a distance of one meter from the equipment in all direction.
b) Routine Tests
i) Checking of obligatory dimensions and clearance of impeller fixing and locking
arrangement.
iv) Condition of bearing by shock pulse meter.
v) Visual check workmanship and DPT on impeller welding to be done which shall
include checkup of welding, painting, workmanship etc.
vi) Noise measurement at a distance of one meter from the equipment in all direction.
Unless otherwise specified in the contract the test and the method of measurement adopted
shall comply within Indian standards specifications for centrifugal flow fans.
Page 8 of 22
14.3.1 DETAILS OF TYPE TESTS
14.3.1.1 Air delivery test
Test shall be carried out with the supply to the driving motor maintained at 415 (+-10%) at
50Hz. However it is desirable to conduct the tests at 33 Hz also with supply from the
VVVF drive. Adequate number of observations shall be made on both sides of the operating
point to plot the characteristic curve. Measure the following quantities.
i) Line voltage
ii) Line current
iii) Power input
v) Total pressure.
vi) Ambient temperature.
The manometer pressure readings shall be taken at least at 4 points to arrive to arrive at a
mean value as per IS 4894.
Calculate the blower output at standard conditions Wt=1.2 kg/m 3 .The standard procedures
to be followed for calculation for fan delivery parameters is given under Annexure-II.
14.3.1.2 Starting time test
With a test installation similar to that adopted for the air delivery test, start the blower
successively at 415V and 373V. Measure oscillographically or by any other
accurate/superior methods for measuring starting time of the motor for oil cooling blower
unit from zero speed to the full speed. Record final load current and voltage reading.
Starting current, running current, starting time at full load at 373V, 33Hz and 415V, 50Hz to
be recorded.
14.3.1.3 Starting duty test
The oil cooling unit shall be subjected to repeated start and stop cycling for 1000 times at a
supply voltage of 415V. The ‘ON’ and ‘OFF’ period shall be 1 minute in each case. If the
unit takes more than 1 minute to stop fully the next start shall commence immediately after
the unit has stopped. At the end of the test the efficacy of impeller locking device shall be
checked; the impeller shall then be dismantled and various parts like key, key way and the
fit of the impeller on the shaft shall be examined for abnormal wear.
14.3.1.4 Endurance test
This test shall be conducted for a period of 48 hours with rated output and head and with a
415 V supply at the motor terminals. After the test the blower and the motor shall be
dismantled and examined for wear and tear of the parts conditions of rings and bearings etc.
14.3.1.5 Shock &vibration level test.
For the measurement of vibration intensity on electronic vibration measurement equipment
having a frequency range of 5 to 2000 CPS, shall be employed. The machine under test shall
be mounted in accordance with IS: 4729.Vibration measurement shall be made at the
bearing housing of the machine which shall operate at no load at rated voltage and at rated
speed.
Limits of vibration intensity: The peak to peak value shall not exceed 25 microns on
motor body, foot and bearing of motor and 40 microns at blower casing.
Page 9 of 22
14.3.1.6 Condition of bearing by shock pulse meter
Condition of bearing shall be checked at rated voltage. The deflection shall be within green
zone of the instrument.
14.3.1.7 Testing of material and welding strength.
(i) Suitable size of test piece of material used for manufacturing of impeller shall be
prepared for testing the tensile strength of material.
(ii) two sets of test piece shall be welded & be kept ready for checking the welding
strength.
Note: The test for welding strength shall be preferably be done in firms premises, However
same may be tested at government accredited laboratory if facility is not available.
14.3.2 DETAILS OF ROUTINE TESTS
Same as item no: 14.3 b) and its procedure given in type test 14.3.1
15.0 Field Trial
Oil Cooling Unit with Casing shall be subjected to extensive field trials for a period of at
least 12 months after fitment on locomotives. During field trials; performance of the OCU
with casing shall be observed & recorded. Based upon the field performance of OCU with
casing; RDSO will consider the prototype approval accordingly.
16.0 List of Drawings
The drawings are for guidance, However , the dimension are to be followed strictly so as to
ensure interchangeability of motor, impeller and casing with other makes.
SN Drawing No. Title Page no.
i CLW/ES/3/SK-2/0647 Motor(200L) for oil cooling unit for
transformer/converter
ANNEXURE-IV
transformer/converter (for guidance
ANNEXURE-VI
v CLW/ES/3/SK-6/0647 Support for bracket , rubber gasket,
looming bar & MS channel
ANNEXURE-IX
ANNEXURE-I
1. Blower
and 20 0 C
(iii) Rated speed : 2920 rpm
(iv) Driving motor : 30kW Squirrel cage Induction Motor
(v) Details of Pressure drops
- Cooler section ,air
Totally enclosed surface cooled as per
RDSO specification No.E-10/3/09(Motor)
(ii) Frame Size & Mounting
(iii) Motor Rating:
(c) Rated Voltage : 415 +/-10%V,3 Phase
(d) Rated Current : 50Amp
(g) Type of Enclosure : TESC
(h) Duty cycle : S1 continuous
(i) Wave form : Quasi-square wave
(j) cosφ : Not less than 0.84
(k) Efficiency : Not less than 88%
(l) Bearing Size : DE & NDE 6312-open type
Make: From RDSO approved sources of
relevant size
winding wire of RDSO approved make
should be used)
(n) Harmonics in Voltage : 50%
(o) Harmonics in current : 50%
(p) dv/dt : Less than 1000V/micro second
Note: - Other parameters & performance requirement of motor will remain same as mentioned
in RDSO specification No. E-10/3/09 (Motor).
3. Starting performance: The blowers shall accelerate from stop to the full speed within 6
seconds over the entire range of supply voltage i.e.415±10%.
4. The following tolerance shall be applicable:
Characteristics
Speed
-5%
±10%
5. The centrifugal flow fans covered by this specification are capable of working against
pressure.
ANNEXURE-II
STANADARD PROCEDURES FOR CALCULATION OF FAN DELIVERY PARAMETERS
1. Test set up for air delivery shall be as per IS 4894.
2. Make a sketch of testing duct and record various dimensions of test set up arrangement.
3. Air delivery test shall be carried out at 373V, 415V and 457V, all at 50Hz, 3 phase power supply to
driving motor.
4. Starting from full open position to full close ,adequate number of measurements on either side of duty
point shall be recorded as per procedure given in IS 4894 so that sufficient data point becomes
available for drawing a smooth fan characteristic curve. In any case, at least 2 readings on either side
of duty point and one reading near duty point must be taken. The suitable no: of charges of mesh with
difference holes simulating to 25% ,50% & 75 % closing shall be available in line with IS 4894.
Observed values starting from full open to full
close position
Pressure at section AA(Paa) in mmWG
Pressure at section BB(Pbb) in mmWG
Test speed in rpm
degree Celsius
5. For each of above observations, the values of air flow, fan total pressure, fan static pressure; fan
efficiency and overall combined unit efficiency shall be calculated and shall be converted at rated
speed and temperature.
6. From the values of air flow and fan total pressure at rated speed and temperature, Fan characteristics
curve along with system resistance curve shall be drawn. The curves for fan efficiency and static
pressure versus flow shall be drawn on same graph. The intersection of fan characteristics curve and
system resistance curve shall be taken as operating point of the fan. The operating point should fall on
right side of the specified fan duty point.
7. Three set of observations, calculations sheets and curves for 373 V, 415 V and 457 Volts shall be
furnished.
8. Calculation sheet along with formulas to be used for determining fan characteristic curve & efficiency
is as under.
Rated Q(m 3 /s)
Rated RPM
Fan Dia
Test Duct Area(sq m)
Fan Outlet area(sq m)
Coefficient of discharge, Cd
to full close
section BB,
Wt(kg/m 3 )
1.2 X
(B+0.0737Ps)
Volume at rated
Rated speed
Qv X
Test speed
Q1
3600
FTP at rated RPM
and temp Rated rpm
rated speed & temp
Fan efficiency (%) Air Power
Motor input
Record details of equipment’s used and their calibration due date .Calculation is to be carried out from
observed values as per above formula .
Page 15 of 22
ANNEXURE-III
1. Blower
A.1 Type, model and make.
A.2 Air delivered in cubic meter per minute and total head in mm WG corrected to 20 0 C and 760
mm barometric pressure at rated voltage
A.3 Design data
a) Impeller diameter.
c) Number of blades.
d) Method of fixing of the blades.
e) Clearance between inlet cone and impeller (maximum 6mm and minimum 1.5mm)
f) Maximum shaft speed of the impeller.
g) Motor shaft and impeller bore diameter (maximum and minimum)
h) Method of fixing of impeller on motor shaft and locking arrangement.
i) GD 2 value of the impeller (indicated the maximum variation in manufacture).
J) Stress calculation for impeller and casing.
Note: - GD 2 value of the impeller will be made use for calculating the starting performance of
the blower with regard to the specified electric motor. As such the value to be
furnished should take into account the inertia, the friction and the resistive torque of
the impeller while it is being started.
A.4 The manufacture shall furnish the speed- torque characteristic of the blower. This is required
for matching the motor and the impeller.
A.5 Torque necessary for the blower when working against constant rated head and delivering
the rated output.
A.6 The supplier shall enclose the following characteristic curves at 20 0 C and 55
0 C.
c) Air horse power vs. air delivery.
d) Power absorbed vs. air delivery.
e) Speed vs. Air quantity in m 3 /sec.
A.7 Vibration level in microns.
A.8 Furnish the welding strength calculation for the joint between impeller and back plate and
cone.
strength.
A.10 Necessary dimensioned drawings of the blowers and its all components showing the
constructional and material specification as per IS or any other relevant international standard
for assembly details shall be submitted.
2. Data sheet for Motor
1 Application
2 Type
a) Rated voltage (415V)
17 Size of bearing and their estimated L10 life
18 Weight of the motor
- Weight of rotor
19 Rotor construction
20 GD 2 value of the rotor(indicate the maximum variation)
21 Starting current and torque in kgm
a)at 373 V
b)at 457 V
c)at 415 V
22 Any deviation from the specification indicating reasons thereof may please be explained.
23 Corona resistant winding wire used as per amendment no 3
Page 17 of 22
Annexure-IV
Annexure-V
Annexure-VI
Annexure-VII
Annexure-VIII
Annexure-IX

specification for oil cooling unit with casing for

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