37911206 ups fundamentals

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UNINTERRUPTIBLE POWER SUPPLY



1. Power Fundamentals2. Power Problems.

* Types of Power Problem.

* Solutions/Protection.

1. Types Of UPS systems.

2. UPS tech. Specs Fundamentals.

1) Power Factor

2) Crest Factor

3) Voltage Regulation

4) a) Line Interactive specs. b) On Line specs.

1. Battery.

2. Power Drawn by Computer.

3. Comparison Of Line Interactive & On-Line UPS systems.



INDEX:INDEX: POWER FUNDAMENTALS

POWER PROBLEMS (a)TYPES (b)

PROTECTION

UPS SYSTEMS

TYPES OF UPS DIFFERENCE BETWEEN

LINE INTERACTIVE AND

ON LINE UPS

TECHNICAL TERMSASSOCIATED WITH UPS

BATTERIES

DATEX



POWER FUNDAMENTALS

VOLTAGE

CURRENT

RESISTANCE DC VOLTAGE

AC VOLTAGE

POWER

FREQUENCY WAVEFORM

TRANSFORMER



Power FundamentalsPower Fundamentals VoltageVoltage : is the source of power that makes the

current flow and helps the electrical

appliances to perform their functions.

Symbol: V Measured in:

V olts. In our household

we get : 220volts



VOLTAGE

Voltage is the electrical force that moveselectrons through a conductor. Voltage is

electrical pressure also known as EMF (Electro

Motive Force) that pushes electrons.

The greater the difference in electrical potential push (difference between positive and negative),

the greater the voltage force potential.



MEASUREMENT

VOLTMETER measures the voltageotential across or parallel to the circuit.The

Voltmeter measures the amount of electrical ressure difference between two points

being measured.Voltage can exist between

two points without electron flow.



CURRENT (AMPERES)

CU RRENT is the quantity or flow rate of electrons moving past a

point within one second. C urrent flow is also known asamperage, or amps for short. It is similar to flow of water in a pipe.

Higher voltage will produce higher current flow, and lower voltage will produce lower current flow. Just like higher pressuremakes more water flow, and less pressure means less water flow.



MEASUREMENT Of Current

An AMMETER AMMETER measures the quantity of current flow.

Ammeters are placed in series (inline) to count the

electrons passing through it.

ExampleExample: A water meter counts the gallons of water flowing through it.



Power FundamentalsPower Fundamentals

CurrentCurrent :: It refers to flow of electric

charge.Current has been the result of motion

of electrons or ions under the influence of an

e.m.f. or we can simply say it is a flow of

electrically charged electrons.

Symbol: I

Measured in : Amperes (A).



Electrical Fundamentals

Units of measurement of Current

Current flow is measured in units called

Amperes or AMPS.

Amperage measurements can use different value

prefixes, such as micro-amp, milli-amp, and Amp.

AMPERAGE Symbol µAµA mAmA AA

Pronounced Microamp milliamp Amp

Multiplier 0.000001 0.001 1



RESISTANCE

Resistance is the force that reduces or stops the flow of electrons. It opposes voltage.

Higher resistance will decrease the flow of electrons and

lower resistance will allow more electrons to flow.

Therefore a Load with less resistance will cause more current to flow

through it. That is why a short circuit in an electrical line causes infinite

amount of current to flow, as there is zero resistance.This causes heating

and eventually burning of the wire.



MEASUREMENTMEASUREMENT

An OHMMETEROHMMETER measures the resistance of an electrical circuit or component. No voltage can be applied while the

ohmmeter is connected, or damage to the meter will occur.

Example:Example: Water flows through a garden hose, and someone steps on the hose. The greater the pressure placed on the hose, the greater the hose restriction and

the less water flows.



RESISTANCE FACTORSRESISTANCE FACTORS

Various factors can affect the resistance. Theseinclude:

LENGTH of the conductor. The longer theconductor, the higher the resistance.

DI AMETER of the conductor. The narrower theconductor, the higher the resistance.

TEMPER AT U RE of the material. Depending on thematerial, most will increase resistance as

temperature increases.

PHYSI CAL C ONDITION (D AM AGE) to the material. Any damage will increase resistance.

TYPE of M ATERI AL used. Various materials have a

wide range of resistances.



DIRECT CURRENT (DC)DIRECT CURRENT (DC)

Electricity with electrons flowing in only one direction is called Direct C urrent or

DC .

DC electrical systems are used in cars.



ALTERNATING CURRENT (AC)ALTERNATING CURRENT (AC)

Electricity with electrons flowing back and forth, negative- positive- negative, is called Alternating C urrent, or AC .

The electrical appliances in your home use AC power.



Power FundamentalsPower Fundamentals

PowerPower :It may be defined as the rate of energy

transfer (or work done) by or to a system.In an

electrical system power has been given by V I,

where V is the potential difference across a

conductor and I the current through it.

Symbol : P Measured in

: Watts(it is the energy transfer in joules per second).



Power ( P ) = Volts X Amp. ( VA)

Another unit for power is Watts.

W hat is the relation between VA and

watts ?

There are two types of electrical loads

1. Purely resitive

2. Inductive or Capacitive collectively

called reactive loads.



In purelyIn purely resistive loadsresistive loads

VA = Watts or VA is same as watts.

Examples of purely resistive loads are

Electric Bulbs, heaters, toasters etc.

What it means is that the load is consumingand converting all electrical energy into

heat and/or light energy.



There are other types of loads which behave in a different

manner, when a voltage is applied to them a current flows

through them but they do not consume all the current passing through. Examples of such loads are

Motors like in Fans, Air conditioners, transformers,

elevators etc.

Some amount of current keeps flowing in the system without

being consumed. In this case

Watts { VA

and VA > watts

The ratio of VA to Watts in such types of loads is

called Power factor Power factor.

Ø = watts / VA



Sine Wave Form

One Cycle

T

Frequency ( f ) = 1/ T

Peak Voltage = 320 V

R.M.S. Voltage = 220 VAverage Voltage = 207 V

T = 20 msec,

f = 1/20 m sec = 50 Hz

A.C. Voltage as it comes in our householdsA.C. Voltage as it comes in our households



The common voltage which comes in our households is known as

Sine W ave.

As is clear from the diag. This voltage keeps alternating between

positive and negative.

It starts from Zero, continuously increases to reach a peak of

about 320 Volts, then starts decreasing to zero again and

continues the reducing trend to reach a negative peak of -320 V.

It then again starts increasing to Zero Volts. This is one complete

cycle, which is then repeated again and again.

Time taken to complete one cycle is 20 milisecond.

And it traverses 50 cycles in one second. This is known as

frequency.The peak AC voltage is 320 Volts , and RMS voltage is 220 Volts.



TransformerTransformer

A device which is used for changing the voltage of an

alternating supply. Transformers are not having moving parts and operate by the current in one coil , the Primary

winding, electromagnetically inducing a current in

another , the Secondary winding,which forms part of a

separate electrical circuit.The ratio of the voltages in the

primary and secondary circuits , V1/V 2 has been approx.

equal to the ratio of the number of turns in the primary

and secondary coils .

STEP UP transformers are used to increase voltage and

reduce the current of the output from power stations sothat losses in transmisssion lines are minimised.The

voltage gets reduced in stages by STEP DOWN

transformers nearer the user.



Types Of TransformerTypes Of Transformer

Step Up Step Down

Isolated

Step Up Step Down

Automotive

Transformer



What are power problems ?

How do they affect working of computers ?

What are the ways to cure them ?



Black Out

Brown Outs- (dips)

Spikes

Sags

Surges

Line noise

Continuous Low and High Voltages



BLACK OUTSBLACK OUTS

* Implies total power failure

Cause : Excessive demand on the power grid, snapping of

power cables, load shedding by electricity supply

boards.

Effects :* Loss of data stored on the hard drives due to sudden switching

off of the computer systems.

* Loss of work due to non functioning of Computers.

* Frequent corruption in Operating system and application soft-

wares which need to be loaded again and again. Resulting in loss

of Many Man hours and delays in meeting deadlines.



BROWN OUTS/ DIPSBROWN OUTS/ DIPS

* Implies a significant drop in voltage .

* Cause :(i) Start up power demands of many electrical devices

(Like motors, compressors, elevators etc).

(ii)Electric utilities lowering voltage levels to cope with

extra ordinary power demands which are in excess of the

generating capacity.

* Effects : Possibilities of frozen keyboards and unexpected system

crashes. Resulting in Hanged motherboards.



SURGESSURGES

* Implies a short term increase in voltage typically lasting1/120th of a second.

*Cause : High powered electrical motors in air conditioners,

house hold appliances etc. when switched off, causes

extra voltage to be dissipated through the power line.

*Effects: Delicate components can get stressed and this can cause

system failure.



A/C

Elevator

TUBE-

LITE

FANS

PCs

MOTOR



SPIKESSPIKES* Implies an instantaneous increase in voltage of a very high

orders.

* Cause :Typically caused by a nearby lightning strike or by

power lines being broken in a storm etc.

* Effect : Catastrophic damage to hardware. Loss of data`

Upto 2000



Transmission

Line

GENERATION

OF ELECTRIC

CONSUMER

LIGHTNING

Electric what



LINE NOISELINE NOISE

* Implies Electro Magnetic Interference (EMI) & Radio Frequency Interference (RFI) in the line.

* Cause : Electrical noise is caused by lightning, load switching,

generators, radio transmitters & industrial equipment.

* Effect : Noise introduces glitches & errors into executable

programs and data files.



Types of Protection-Stabilizers

- Servo Stabilizers

- Spikebusters- CVTs

- UPS Systems



SERVO STABILIZERSSERVO STABILIZERS

* Maintains a stable output in the presence of an erratic

fluctuating input but has a slow response.

* It is not so suitable as the only protection device for computers

because of their slow response and they are useless during apower failure.



STABILIZERSSTABILIZERS

*It is a machine which gives stabilize /regulated

output for a particular input range.Operation is

achieved by the help of auto transformer and

electromechanical relays.



SPIKEBUSTERSSPIKEBUSTERS

* It reduce the severity of voltage spikes on the mains line.

* But they can neither provide a regulated output nor provide

power in the event of a power failure.



CVTsCVTs

* It produce a very stable out-put voltage.

* It can remove voltage sags & surges from the mains voltage quite

effectively.

* But CVTs are expensive and noisy.

* They are useless in the event of a power failure.



UPS SYSTEMSUPS SYSTEMS

* Protect the computer & other power sensitive equipments incase

of power failure.

* Ensures a regulated stable output and additional filtering duringspikes and surges.



Off-line

On-lineLine-Interactive UPS



Off -Line DATEX UPS systems

have a battery power conversion circuit with a switch that senses power irregularities and automatically switches to

battery.

The main drawbacks of offline UPSs are that theyoffer only limited regulation

and have a comparativelylarger switchover time.

Charger Battery

Off -Line

AC

InputAC

Output

AC

AC



In Datex Online UPS system,even in the presence of mains, the computer is always powered by the battery/inverter circuit.

Another charger circuit keeps charging the battery.

Theres no switchover involved.

Online are more complex,

bulkier and more expensive but offer a better Voltage regulation and pure sine wave output.

By Pass Switch

Battery

On-Line

AC

OutputAC

DC

ACAC

Input



Similar to the offline units,

Datex UPSs also switch to

battery whenever input voltage

hits predetermined levels.

Line-interactive models provide voltage regulation features and

have lesser switchover time and

better performance than the

offline models.

They provide better protection

against spikes and switching

transients.

Regulator

Battery

Line Interactive

AC

Input

Buck/

Boost

AC

Output

DC

AC

Discharge Charge

COMPARISON BET W EEN LINE INTERACTIVE AND ONLINE UPS SYSTEM



FEATURES

LINE INTERACTIVE

UPS

ON LINE UPS REMARKS

COST ECONOMICAL EXPENSIVE LI is more economical ascompared to Online ups.

VOLTAGE

REGULATION

ADEQUATE

(220s 10%)

EXCELLENT

(220s 2%)

Online¶s voltage regulation ismuch superior than LI.

TRANSIENT

RESPONSE

O.K EXCELLENT LI takes typically 20 to 50 ms tocorrect a voltage and also some

amount of transition always passed on the load. But online

UPS output is completely isolatedfrom input hence, no transient is

carried to the load.

W AVE FORM

QUASI SINEWAVE(MOSTLY)

PURE SINEWAVE There are some voltage sensitivedevices which require pure sinewave which can be only provided by online ups.

TRANSFER TIME

5 ±10 Millisecond ZERO Online ups provides purelyuninterrupted and regulated

supply to the load.

SERVICEABILITY

EASY TO SERVICE LITTLE DIFFICULT TOSERVICE

Because of compact size and

simple design LI is easy to serviceand replace as and when requiredand online is little difficult to

service bcz of its complicateddesign.

SIZE

COMPACT BULKY LI is small and relatively moreuser-friendly.



Comparison on the basis of costComparison on the basis of cost

Line-Interactive On-Line Remarks

Economical Expensive LI is more economical as

compared to Online UPS.



Comparison on the basis of VoltageComparison on the basis of Voltage

Regulation.Regulation.


Adequate Excellent Online¶s voltage

regulation is

much superior

than LI.



Comparison on the basis of Comparison on the basis of

Transient ResponseTransient Response


O.K Excellent LI takes typically 20

to 50ms to correct a

voltage and also some

amount of transition is

always passed on the

load .But Online UPS

output is completely

isolated from input

hence ,no transition is

carried to the load



Comparison on the basis of WaveComparison on the basis of Wave

FormFormLine-Interactive On-Line Remarks

Quasi Sine wave

(Mostly)

Pure Sinewave There are some

voltage sensitivedevices which

require pure sine

wave,which can be

only provided by

On-Line UPS.



Comparison on the basis of TransferComparison on the basis of Transfer

TimeTimeLine-Interactive On-Line Remarks

5-10 Millisecond Zero Online UPS provides purely uninterrupted

and regulated supply

to the load.




ServiceabilityServiceability


Easy to Service Little

difficult to

Service

Because of compact

size and simple

design LI is easy to

service and replaceas and when

required and online

is little difficult to

service because of

its complicated

design.



Comparison on the basis of SizeComparison on the basis of Size


Compact Bulky LI is small andrelatively more user-

friendly.



Comparison on the basis of WeightComparison on the basis of Weight


Light Heavy LI occupies

less space and

can be

conveniently

moved around.




CapacityCapacity


Maximum Rating

upto 3KVA

Any rating Customer gets

wider choice in

On-Line UPS

system.



Rating (VA & Watt)Transfer Time

Input Voltage Window

AVR (Voltage Regulation)Backup Time

Crest Factor

Transient response



UPS RATINGUPS RATING

VA = V x I (volt ampere)

Watts = V x I x Power factor

(watts is the actual energy consumed per unit time by an electrical load)

Power factor = Cosø

(the ratio of actual power to reactive power is called power factor)

(For Datex Accure power factor is 0.8/>4.0)

(For Datex Clarrion power factor is 0.7 to unity)



TRANSFER TIMETRANSFER TIME

Switch over time in case of power failure from mains

mode to the battery mode.

(For Datex Accure it is typically 2-3msec.)

(For Datex Clarrion it is Zero as in this case there is no transfer

time.)

.



INPUT VOLTAGE WINDOWINPUT VOLTAGE WINDOW

Input voltage range within which the UPS continues to be in the mains

mode.

(For Datex Accure input voltage window is 150-270 V )

(For Datex Clarrion input voltage window is 160-280 V)



AVRAVR

(Automatic Voltage Regulation)(Automatic Voltage Regulation)

This is a feature which provides a regulated output voltage to the load

& protects the load from voltage fluctuations.

(Datex Accure regulates output voltage within 220V ± 8%)

(Datex Clarrion regulates output voltage within 220V ± 1%)



BACKUP TIMEBACKUP TIME

The time period for which the UPS can supply

power to the recommended load in the battery

mode is known as backup time.



CR EST FACTOR CR EST FACTOR

It is defined as the ratio of Peak power load to

average power load.

In case of DATEX it is >3



TR ANSIENT R ESPONSETR ANSIENT R ESPONSE

It is a sudden fluctuation in voltage lasting

from 100th of a second to few seconds.

( In case of Datex Accure it is 20 to 50 ms).

( In case of Datex Clariion it is zero).



Battery Fundamentals

THE AUTOMOTIVE BATTERY



THE AUTOMOTIVE BATTERY

A lead-acid storage battery is an electrochemical device that producesvoltage and delivers electrical current. The battery is the primary

"source" of electrical energy used in vehicles today. It's important toremember that a battery does not store electricity, but rather it stores

a series of chemicals, and through a chemical process electricity is produced. Basically, two different types of lead in an acid mixture

react to produce an electrical pressure called voltage. Thiselectrochemical reaction changes chemical energy to electrical energy

and is the basis for all automotive batteries

Battery Basics



Battery Basics

CELL VOLTAGE

Each cell element of the battery producesapproximately 2.1 volts, regardless of the quantity orsize of the plates. Automobile batteries have six cells

that are connected in series, which produces a totalvoltage of 12.6 volts.



BATTERYBATTERY

Specifications:-

(1) Voltage 12V 6V & 2V Cells

(2) Ampere Hour (AH)



BATTERY CHARACTERSTICS

TYPES OF BATTERIES

-Ni Cd Batteries

-Lead Acid



Ni Cd Batteries

Used for low power applications like, mobile phone,

cordless phones etc.



Lead Acid Batteries

Used for high power applications, like UPS, Telephone exchange,Automobiles.

There are two types of Lead Acid Batteries

-Sealed Maintenance free (SMF)

-Automotive



DIFFERENT BATTERIES GENERALLY IN USE

-12V 7AH

-12V 17AH

-12V 28AH

-12V 45AH

-12V 65AH

-Automotive 150Ah (trucking battery) exide.



Lead Acid Ni cd

HighPower

Choice

for UPS Low Power

Automotive

TYPES OF BATTER IES

Sealed

Maintenance

free (SMF)

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