Brushless ALTERNATOR Customer Training [PDF]

Zitiervorschau

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ALTERNATOR RANGE Brushless 5KVA To 1010KVA,1500rpm,3-Ph,415Volt Brushless 5KVA To 50KVA,1500rpm,1-Ph,240Volt Brushless 5KVA To 30KVA, 3000rpm,3-Ph,415Volt Brushless 5KVA To 15KVA,3000rpm,1-Ph,240-Volt

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AL. BODY ALTERNATOR ( 160 FR: 15 - 30KVA)

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AL. BODYALTERNATOR(200 FR: 35 -90kVA)

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AL.BODY ALTERNATOR(250 FR: 100-200kVA )

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FAB. BODY ALTERNATOR(315/355&400FR:250-1010kVA)

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WHAT IS ALTERNATOR..? Alternator or AC Generator is a Electrical Rotating M/c, which converts Mechanical INPUT power into Electrical output Power.

TYPES OF ATERNATOR 1. Brush less Alternator :- As the name indicates there is no slip ring & brushes for feeding the the DC power to Field winding. 2. Slip-ring Alternator :- There is slip ring & brushes for feeding the the DC power to Field winding. 7

SALIENT FEATURES OF CGL ALTERNATORS


Al. alloy gravity die cast stator body - Pleasing look & light in weight.




2/3 rd pitch windings : Offers better suitability for Non-linear loads.




Efficiencies - Better/ at par with competitors.




Spacious Terminal box with provision of double side entry – Flexibility & Ease of Al. customer cables termination inside the box.




Out-board Diode board assembly (as against inboard in case of competitors)- Ease of service.




Epoxy gel treatment on Winding overhangs : Offers better suitability for tropical environment.




Life long lubricated sealed bearings.

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DECODING OF MACHINES AND EXCISE REF. NO.

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STD./OPTIONAL TECHNICAL SPECN

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OPERATION PRINCIPLE OF BRUSHLESS ALTERNATOR

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FEW COMPONENTS

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Exciter Rotor & Main Rectifier Assembly Exciter Rotor 3 Phase with Internal Star Point

SHAFT

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Exciter Rotor & Main Rectifier Assembly Exciter Rotor with Internal Star Point

Rectifier Assembly

To Main Rotor

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Main Rectifier Assembly- Operation of a Diode +VE ✲ A.C Input to Rectifier Diodes ✲ Rectifier Diode Positive Heatsink Cathode Stud

+

0 -VE +VE 0 -VE

✲ Rectifier Diode Negative Heatsink Anode Stud

+VE 0 -VE

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Main Rectifier Assembly- 3 Phase Rectification ✲ A.C Input to Rectifier Diodes

+

✲ D.C output to Main Rotor

✲ Full wave 3 Phase rectification will produce a D.C output

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Metal Oxide Varistor (Surge Suppressor)

Diode Protection Device For Transient Suppression

SHAFT

Main Rotor Connections

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Main Rectifier Connections to Main Rotor

Main Rectifier ✲ Aluminium bus bar

SHAFT

Main Rotor

D.C

✲ The Rectifier Output is a smooth D.C Supply across the Aluminium bus bars ✲ This is fed to the Main Rotor windings

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What does “BRUSHLESS BRUSHLESS” BRUSHLESS Generator mean? D.C. FIELD POLES

OUTPUT

CARBON BRUSHES

A.C.ARMATURE

SHAFT

SLIPRINGS BEARINGS

✲ Long back CG Generators were designed with SLIPRINGS and CARBON BRUSHES, to transfer power from the rotating component of the Generator. ✲ These had a tendency to wear out, spark, burn, with vibration or high transient load currents. ✲ ‘BRUSHLESS’ Generators are designed to allow output to be taken from the Generator WITHOUT SLIP-RINGS AND BRUSHES.

NOW LET’S LOOK AT A BRUSHLESS GENERATOR !! 19

Double Bearing Main Rotor Assembly Main Rotor Exciter Rotor

Fan

Bearings

Rectifier

Bearings are sealed for life.
Rotating rectifier assly is fitted to the non drive end of the Exciter rotor




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Single Bearing Main Rotor Assembly Main Rotor Exciter Rotor

Fan

Bearing

Rectifier

✲ Drive End of Generator Shaft is supported by the Engine Flywheel ✲Sealed bearing for life time

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Wound Main Stator Assembly ✲ ✲ ✲ ✲ ✲ ✲

Core built from high grade Electrical Steel, to reduce Iron losses (heat). Each lamination is electrically insulated to minimise Eddy Currents in the core. 12 Ends Out Re-connectable, 6 Ends out Star / Delta, or Dedicated Windings. Class ‘H’ Insulation as standard, 125 º C Temperature rise in 40º Ambient. 2/3rds Pitch windings, Multiple of 3 ( 3rd, 6th, 9th ect.), Harmonics are eliminated. VPI Impregnation with Class H resin as standard.

Laminated Steel core

Copper Windings

Output Leads

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Wound Main Rotor - Coil Group connections ANTI CLOCK

D.C Input From Main Rectifier

S CLOCK

N

N

CLOCK

S ANTI CLOCK

✲ The Rotor coils are connected in Series (4 Pole Rotor shown). ✲ Each coil is reversed to the adjacent coil, producing the required polarity

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Wound Main Rotor - Poles & Frequency Generator Frequency (HZ) = Speed (N) X Pairs of poles (P) 60

2 Pole

4 Pole

SHAFT

S

N N

N

S

SHAFT

S

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Main Rotor- Damper Windings

SHAFT

✲Damper Bars ✲Aluminium Damper Bars Welded to End Plates

N

N

S

S

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Main Rotor- Amortisseur (Damper) Windings

SHAFT

N

N

S

S ✲ Helps dampen speed oscillations resulting from cyclic irregularities in the engine, (cause of ‘light flicker’). ✲ Stabilises the mechanical systems during large load changes. ✲ Stabilises load sharing with other Generators in Parallel. ✲ Improves Harmonic Distortion in the Generator waveform

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Excitation System - Exciter Stator Exciter Stator

Main Stator Exciter Rotor & Stator Bearing

Main Rotor

Shaft

Rectifier Fan

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Excitation System - Wound Exciter Stator X+ (F1) XX- (F2)

To A.V.R Terminals

COIL CONNECTIONS

N

S

N

S

✲ High-remanence steel core ✲ Stores Residual Magnetism ✲ High frequency Generator FOR 132/160/200 FRAME = 6 POLES FOR 250/280 FRAME = 6 POLES FOR 315 / 355 FRAME = 12 POLES

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AL Series Double Bearing Alternator Terminal Block

Covers

AVR Main Stator Assembly

V1 W1 U1 V1

Main Rotor Assembly Exciter Rotor Laminated Steel core With RRA

Exciter Stator

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AL Series Single Bearing Alternator Assembled Alternator with Single Bearing Rotor

Coupling Disc / Flex Plate

Disc Tightening Bolts

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EXCITATION SYSTEM

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AVR SR-7/3(5 TO 40KVA) &7/6 (45 TO 200 KVA) SPECIAL FEATURES

SR-7/3

SR-7/6

SR-7/3-1-ph

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UVR7 (180 to 1010 KVA) SPECIAL FEATURES

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UVR7 (180 to 1010 KVA)SPECIAL FEATURES

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AVR-SPECIFICATIONS

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DO’s & DON’T’s

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DO’S      

ENSURE RATED VOLTAGE ON NO-LOAD AT 52 Hz (ENGINE SPEED FOR 1560 RPM) ENSURE THAT ENGINE SPEED IS NEVER BELOW 50 Hz.(1500 RPM) FROM NO-LOAD TO FULL LOAD. ENSURE THAT ALTERNATOR NEUTRAL IS EARTHED PROPERLY ENSURE THAT ALL CONNECTIONS & FOOT FIXING HOLE ARE TIGHTNED PROPERLY TO AVOID VIBRATIONS. ENSURE PROPER AIR CIRCULATION INSIDE THE DG-SET ROOM SO THAT AMBIENT TEMP. IS NOT MORE THAN 40 ‘C . ENSURE THAT MEGGER VALUE OF THE WINDING IS MORE THAN 2MEG-OHMS. (REMOVE ALL THE CONNECTIONS

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DONT’S
DONOT DISTURB AVR POTENTIOMETER SETTING EXCEPT VOLT. POTENTIOMETER
DONOT CHARGE THE ALTERNATOR WHEN AVR IS IN CONNECTED CONDITION & ALTERNATOR IS RUNNING
DO NOT OVER LOAD THE ALTERNATOR .
DO NOT OPERATE THE ALTERNATOR ON LESS THAN 0.8 LAG PF
DO NOT OPERATE ON LEADING POWER FACTOR (CAPACITOR LOAD)
DO NOT MEGGER/HV TEST WINDINGS BEFORE REMOVING THE CONNECTIONS TO AVR
DO NOT OPERATE ON LESS THAN 1500 RPM. (50 Hz)

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1-BRG.SET.ASLY CHECK POINTS  DO NOT APPLY ANY FORCE TO THE ALTERNATOR FAN.  DO NOT REMOVE ANY COUPLING DISC FROM THE SET.  ENSURE “WA” DIMN. AN ENGINE & ALTERNATOR (i.e The dist. from coupling disc face to alternator Flange spigot face. It should be within 0.5mm)  USE ONLY 8.8 CL. SCREWS & HARDEDNED WASHERS  DO NOT USE SPRING WASHERS ON COUPLING DISC  DISC SCREWS TO BE TIGHTEND WITH SPECIFIED TORQUE AS BELOW M10-6 kg-m ,

M12 –10 kg-m ,

M16- 24 kg-m , M20- 48 kg-m

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COMMISIONING & INSTALLATION CHECK POINTS POINT OF OBSERVATION

CHECK POINTS

VISUAL OBSERVATION





ENSURE PROPER EARTHING


Check the voltage on No-load volts

NO-LOAD ELECTRICAL PARAMETERS

No-load freq
For brushless 51.5 to 52 hz
For capacitor type 50-51 hz No-load voltage
For 1-phase 230 or 240 as per N/p
For 3-ph 415v Voltage variation Should be less than 1volt on digital voltmeter having 1digit accuracy

ON LOAD PARAMETERS


Voltage to be measured
Load current to be seen (it should be well within the n/p data)
Freq should not go down below 50hz

GENERAL OBSERVATIONS


Vibration normal or abnormal
If any abnormality in sound

Proper tightening of all screws including base frame There should be no loose connection b/w body and neutral-it should be less than 3

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TROUBLE SHOOTING

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VOLTAGE FAULTS FAULT No voltage built-up

CAUSE 1.Insufficient residual voltage 2. Improper connection 3. Low speed 4. Faulty Winding 5.Rotating rectifier failure 6. Faulty AVR

Low no-load voltage

1. Low speed 2. Faulty Rotating rectifier 3. Faulty Winding

REPAIR 1.Excite the exc.stator using a battery 2. Correct the connection 3. Reset the speed to the nominal 4. Check the wdg. Resistance Rewind if required 5. Replace the rotating rectifier 6. Replace the AVR 1. Reset the speed to the nominal 2. Replace the Rotating rectifier 3. Check the wdg. Resistance Rewind if required

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FAULT

CAUSE

REPAIR

Voltage Oscillations

1. In correct AVR setting 2. Thyristor load more than specified limits

1. Set the AVR stability pot 2. Reduce the Tghyristor load

Unbalance voltage

1. Unbalance Load 2. Loose connections 3. Stator winding faulty

1. Correct the load 2. Tightend the loose connections 3. Check the wdg. Resistance Rewind if required

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FAULT Low voltage on load

CAUSE 1. Low speed at full load. 2. Faulty rotor Winding 3. Over load on Alternator

REPAIR 1. Set the rated speed of the Engine 2. Check the wdg. Resistance Rewind if required 3. Operate on specified load.

High voltage on load

1. Capacitor on the load side

1. Disconnect the PF improvement capacitor

Too high No-load voltage

1. Excessive speed

1. Adjust the speed

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HOW TO SELECT ALTERNATOR RATING

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DERATING FACTORS DERATION FOR AMB. TEMP. DERATING FACTOR

1.05 1 0.95 0.9 0.85 0.8 0.75

D.Factor

40

45

50

55

60

1

0.96

0.92

0.88

0.84

AMB. TEMP

No deration upto Std. Amb : 40°c .

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DERATING FACTORS

CONTD…..

DERATION FOR ALTITUDE. DERATING FACTOR

1.2 1 0.8 0.6 0.4 0.2 0

D.Factor

1000

1500

2000

2500

3000

3500

1

0.96

0.92

0.88

0.84

0.8

ALTITUDE

No deration upto Std. Altitude level : 1000 M . 49

DERATING FACTORS

CONTD…..

DERATION FOR POWER FACTOR( LAG) DERATING FACTOR

1.05 1 0.95 0.9 0.85 0.8 0.75

D.Factor

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

1

0.95

0.91

0.88

0.86

0.85

0.84

0.84

0.84

POWER FACTOR

No deration for UPF to 0.8 Pf 50

SELECTION OF ALT. FOR VARIOUS LOADS

LINEAR LOAD


Includes Resistance,Inductance & Capacitance.




Estimate connected load in KW & operating power factor




Our alternators are suitable for 0.8 lag to Unity pf.

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SELECTION OF ALT. FOR VARIOUS LOADSCONTD….. UNBALANCE LOAD


Maximum unbalance allowed is 25% I.e.( ( I Max – I Min ) / I Max ) * 100 = 25%




Any phase current should not exceed rated current

WELDING LOAD


3 phase welding load should be < 50% KVA rating




1 phase welding load should be < 33% KVA rating

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SELECTION OF ALT. FOR VARIOUS LOADS INDUCTION MOTOR LOAD


Capable of starting 1HP with 1 kVA (upto 10kVA)




Capable of delivering 3.5 times of rated current for 10 Sec.

THYRISTOR LOAD


Generates harmonics which is harmful to alternator,so required derating.




Alternator KVA rating = 1.5 X + Y Where X is thyristor load & Y is linear load. 53

WHY ?… DERATING REQUIRED FOR NON-LINEAR LOADS Due to excess heating because of:


High Hysterisis loss.




High Eddy-Current loss.




Skin effect in armature winding.

NOTE:- NO STANDARD IS AVALIABLE FOR DERATING,

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GUIDELINES FOR NON-LINEAR LOADS LOAD

GUIDELINES

FLOURESCENT LIGHTING LOAD

No derating required.

UPS & TELECOM LOAD CONTROLLED BY A TWELVE PULSE THYRISTOR BRIDGE PLUS A FILTER

Non linear load should not exceed 90% of the alternator rating

UPS & TELECOM LOAD CONTROLLED BY A SIX PULSE THYRISTOR BRIDGE PLUS A FILTER

Non linear load should not exceed 66% of the alternator rating

UPS & TELECOM LOAD CONTROLLED BY A THREE PULSE THYRISTOR BRIDGE PLUS A FILTER

Non linear load should not exceed 35% of the alternator rating

VARIABLE SPEED 6 PULSE THYRISTOR BRIDGE CONTROL DRIVE.

Non linear load should not exceed 50% of the alternator rating

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REMEDIES FOR NON-LINEAR LOAD


Oversize of the neutral conductor (200% of the phase conductor).




Location of isolation transformer close to the load.




Derating of Alternator & Transformer.




Use of true RMS sensing meters & relay.




Select power source with low o/p Impendence.




Provide line filters.

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REMEDIES FOR NON-LINEAR LOAD


Oversize of the neutral conductor (200% of the phase conductor).




Location of isolation transformer close to the load.




Derating of Alternator & Transformer.




Use of true RMS sensing meters & relay.




Select power source with low o/p Impendence.




Provide line filters.

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RELATION B/T STARTING METHOD & STARTING CURRENT METHOD OF STARTING

STARTING CURRENT

DIRECT ON-LINE STARTING (DOL)

6-7 times of the rated full load current ( If starting current is not given than starting KVA is 7 times HP rating)

STAR/DELTA STARTING

2-2.5 times of the full load current

ROTOR RESISTANCE

1.5-2 times the full load current

AUTO TRANSFORMER STARTING 40% Tapping 60% Tapping 80% Tapping

1.2 times the full load current 4.0 times the full load current 4.5 times the full load current

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HOW TO SELECT AN ALTERNATOR…? STEPS




Estimate total KW say-’’X’’




Estimate total power factor say-’’Y’’




Provide 10-15% allowance Alternator KVA rating = ( X/Y ) * 1.15 For Non-linear load contact manufacturer

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HOW TO SELECT ENGINE RATING…..?

ENGINE HP IS GIVEN BY:-

(KVA * PF) /( 0.735 * Efficiency of alternator)

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Thank you

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