Brushless ALTERNATOR Customer Training
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Transcript of Brushless ALTERNATOR Customer Training
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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 Electricaloutput Power.
TYPES OF ATERNATOR
1. Brush less Alternator :- As the name indicatesthere is no slip ring & brushes for feeding the theDC power to Field winding.
2. Slip-ring Alternator :- There is slip ring &brushes for feeding the the DC power to Fieldwinding.
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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 ofcompetitors)- Ease of service.
Epoxy gel treatment on Winding overhangs : Offers better suitability fortropical environment.
Life long lubricated sealed bearings.
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DECODING OF MACHINES ANDEXCISE REF. NO.
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STD./OPTIONAL TECHNICAL SPECN
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OPERATION PRINCIPLE OFBRUSHLESS ALTERNATOR
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FEW COMPONENTS
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SHAFT
Exciter Rotor & Main Rectifier Assembly
Exciter Rotor 3 Phase
with Internal Star Point
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Exciter Rotor & Main Rectifier Assembly
To Main Rotor
Exciter Rotor with Internal Star Point
Rectifier Assembly
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+VE
0
-VE
Main Rectifier Assembly- Operation of a Diode
R Rectifier Diode
Positive Heatsink
Cathode Stud
R Rectifier Diode
Negative Heatsink
Anode Stud
+VE
0
-VE
+VE
0
-VE
R A.C Input to Rectifier Diodes
+
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Main Rectifier Assembly- 3 Phase Rectification
R Full wave 3 Phase rectification will produce a D.C output
R A.C Input to Rectifier Diodes
R D.C output to Main Rotor+
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Metal Oxide Varistor (Surge Suppressor)
Diode Protection Device
For Transient Suppression
Main Rotor
ConnectionsSHAFT
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SHAFT
Main Rectifier Connections to Main Rotor
D.C
Main Rotor
R The Rectifier Output is a smooth D.C Supply across the Aluminium bus bars
R This is fed to the Main Rotor windings
Main RectifierR Aluminium
bus bar
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What does What does What does What does BRUSHLESSBRUSHLESSBRUSHLESSBRUSHLESS Generator mean? Generator mean? Generator mean? Generator mean?
R Long back CG Generators were designed with SLIPRINGS and CARBON BRUSHES, totransfer power from the rotating component of the Generator.
R BRUSHLESS Generators are designed to allow output to be taken from the GeneratorWITHOUT SLIP-RINGS AND BRUSHES.
R These had a tendency to wear out, spark, burn, with vibration or high transient loadcurrents.
SLIPRINGS
CARBONBRUSHES
BEARINGS
NOW LETS LOOK AT A BRUSHLESS GENERATOR !!
OUTPUT
SHAFTA.C.ARMATURE
D.C. FIELD POLES
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Bearings are sealed for life. Rotating rectifier assly is fitted to the non drive end of the Exciter rotor
Double Bearing Main Rotor Assembly
FanMain Rotor
BearingsExciter Rotor
Rectifier
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Single Bearing Main Rotor Assembly
R Drive End of Generator Shaft is supported by the Engine FlywheelRSealed bearing for life time
Main Rotor Fan
Rectifier
Exciter
Rotor Bearing
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Wound Main Stator Assembly
R Core built from high grade Electrical Steel, to reduce Iron losses (heat).
R Each lamination is electrically insulated to minimise Eddy Currents in the core.
R 12 Ends Out Re-connectable, 6 Ends out Star / Delta, or Dedicated Windings.
R Class H Insulation as standard, 125 C Temperature rise in 40 Ambient.
R 2/3rds Pitch windings, Multiple of 3 ( 3rd, 6th, 9th ect.), Harmonics are eliminated.
R 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
S
S
N N
D.C InputFrom Main
Rectifier
R The Rotor coils are connected in Series (4 Pole Rotor shown).
R Each coil is reversed to the adjacent coil, producing the required polarity
ANTI CLOCK
ANTI CLOCK
CLOCK CLOCK
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S
N NS
SHAFT
4 Pole 2 Pole
Generator Frequency (HZ) = Speed (N) X Pairs of poles (P)
60
S
SHAFT
N
Wound Main Rotor - Poles & Frequency
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S
N N
S
SHAFT
RDamper Bars RAluminium Damper Bars Welded to End Plates
Main Rotor- Damper Windings
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R Stabilises the mechanical systems during large load changes.
R Stabilises load sharing with other Generators in Parallel.
R Improves Harmonic Distortion in the Generator waveform
R Helps dampen speed oscillations resulting from cyclic irregularities in
the engine, (cause of light flicker).
Main Rotor- Amortisseur (Damper) Windings
SN N
S
SHAFT
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Exciter
Stator
Excitation System - Exciter Stator
Exciter
Rotor
& Stator
Main Stator
Bearing
Shaft
RectifierFan
Main Rotor
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R High-remanence steel coreR Stores Residual Magnetism
R High frequency Generator
To A.V.R TerminalsXX- (F2)
X+ (F1)
Excitation System - Wound Exciter Stator
N S N S
COIL CONNECTIONS
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
V1V1 W1U1
Laminated Steel core
Main RotorAssembly
Main StatorAssembly
CoversTerminal
BlockAVR
Exciter Rotor 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) SPECIALFEATURES
SR-7/6SR-7/3
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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DOs & DONTs
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DOS
ENSURE RATED VOLTAGE ON NO-LOAD AT 52 Hz (ENGINE SPEEDFOR 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 ARETIGHTNED PROPERLY TO AVOID VIBRATIONS.
ENSURE PROPER AIR CIRCULATION INSIDE THE DG-SET ROOM SOTHAT AMBIENT TEMP. IS NOT MORE THAN 40 C .
ENSURE THAT MEGGER VALUE OF THE WINDING IS MORE THAN 2-MEG-OHMS. (REMOVE ALL THE CONNECTIONS
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DONTS
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
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
ON LOAD PARAMETERS
Vibration normal or abnormal
If any abnormality in sound
GENERAL OBSERVATIONS
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
NO-LOAD ELECTRICALPARAMETERS
Check the voltage on No-load b/w body and neutral-it should be less than 3
volts
ENSURE PROPER EARTHING
Proper tightening of all screws including base frame
There should be no loose connection
VISUAL OBSERVATION
CHECK POINTSPOINT OF OBSERVATION
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TROUBLE SHOOTING
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VOLTAGE FAULTS
1. Reset the speed to the nominal
2. Replace the Rotating rectifier
3. Check the wdg. Resistance
Rewind if required
1. Low speed
2. Faulty Rotating rectifier
3. Faulty Winding
Low no-load
voltage
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.Insufficient residual voltage
2. Improper connection
3. Low speed
4. Faulty Winding
5.Rotating rectifier failure
6. Faulty AVR
No voltage built-up
REPAIRCAUSEFAULT
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1. Correct the load
2. Tightend the loose connections
3. Check the wdg. Resistance
Rewind if required
1. Unbalance Load
2. Loose connections
3. Stator winding faulty
Unbalance
voltage
1. Set the AVR stability pot
2. Reduce the Tghyristor load
1. In correct AVR setting
2. Thyristor load more
than specified limits
Voltage
Oscillations
REPAIRCAUSEFAULT
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1. Adjust the speed1. Excessive speedToo high
No-load voltage
1. Disconnect the PF improvement
capacitor
1. Capacitor on the load sideHigh voltage on
load
1. Set the rated speed of the Engine
2. Check the wdg. Resistance
Rewind if required
3. Operate on specified load.
1. Low speed at full load.
2. Faulty rotor Winding
3. Over load on Alternator
Low voltage on
load
REPAIRCAUSEFAULT
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HOW TO SELECT
ALTERNATOR RATING
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DERATING FACTORS
No deration upto Std. Amb : 40c .
DERATION FOR AMB. TEMP.
0.75
0.8
0.85
0.9
0.95
1
1.05
AMB. TEMP
DE
RA
TIN
G F
AC
TO
R
D.Factor 1 0.96 0.92 0.88 0.84
40 45 50 55 60
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No deration upto Std. Altitude level : 1000 M .
DERATION FOR ALTITUDE.
0
0.2
0.4
0.6
0.8
1
1.2
ALTITUDE
DE
RA
TIN
G F
AC
TO
R
D.Factor 1 0.96 0.92 0.88 0.84 0.8
1000 1500 2000 2500 3000 3500
DERATING FACTORS CONTD..
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No deration for UPF to 0.8 Pf
DERATION FOR POWER FACTOR( LAG)
0.75
0.8
0.85
0.9
0.95
1
1.05
POWER FACTOR
DE
RA
TIN
G F
AC
TO
R
D.Factor 1 0.95 0.91 0.88 0.86 0.85 0.84 0.84 0.84
0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0
DERATING FACTORS CONTD..
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SELECTION OF ALT. FOR VARIOUSLOADS
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 VARIOUSLOADSCONTD..
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 VARIOUSLOADS
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,sorequired derating.
Alternator KVA rating = 1.5 X + Y
Where X is thyristor load & Y is linear load.
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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 FORNON-LINEAR LOADS
Non linear load should not exceed 35%of the alternator rating
UPS & TELECOM LOAD CONTROLLED BY ATHREE PULSE THYRISTOR BRIDGE PLUS AFILTER
Non linear load should not exceed 50%of the alternator rating
VARIABLE SPEED 6 PULSE THYRISTORBRIDGE CONTROL DRIVE.
Non linear load should not exceed 66%of the alternator rating
UPS & TELECOM LOAD CONTROLLED BY ASIX PULSE THYRISTOR BRIDGE PLUS AFILTER
Non linear load should not exceed 90%of the alternator rating
UPS & TELECOM LOAD CONTROLLED BY ATWELVE PULSE THYRISTOR BRIDGE PLUSA FILTER
No derating required.FLOURESCENT LIGHTING LOAD
GUIDELINESLOAD
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REMEDIES FORNON-LINEAR LOAD
Oversize of the neutral conductor (200% of the phaseconductor).
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 FORNON-LINEAR LOAD
Oversize of the neutral conductor (200% of the phaseconductor).
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
1.2 times the full load current
4.0 times the full load current
4.5 times the full load current
AUTO TRANSFORMER STARTING
40% Tapping
60% Tapping
80% Tapping
1.5-2 times the full load currentROTOR RESISTANCE
2-2.5 times of the full load currentSTAR/DELTA STARTING
6-7 times of the rated full load current
( If starting current is not given than startingKVA is 7 times HP rating)
DIRECT ON-LINE STARTING (DOL)
STARTING CURRENTMETHOD OF STARTING
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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