ALTERNATOR

TECHNICAL TRAINING
 Alternator Parts List

No. Nbr. Description No. Nbr. Description

1 1 Stator assembly 107 1 Support diode assembly
4 1 Rotor assembly
y 124 1 Terminal p
plate
15 1 Fan 198 1 Regulator(AVR)
16 6 Fan fixing screw 207 1 Rubber
28 1 Earth terminal 290 1 Housing
30 1 DE flange 291 1 Adaptation shaft
33 1 Air outlet louvre 292 1 Rotor magnets
36 1 N.D.E.bracket 293 1 Stator
37 4 Tie rod 294 2 Fixing screw
41 1 D.E.terminal box 295 1 Tie rod
47 1 N.D.E.terminal box 296 1 Washer & nut
48 1 Terminal box lid 297 1 End plate
49 20 Terminal box fixing screw 320 1 Hub
51 1 Air intake louvre 322 1 Coupling disc
59 3 Inspection door 323 Fixing screw
70 1 NDE bearing 324 1 Clamping washer
79 1 Preloading wavy washer 325 Spacer shim
90 1 Wound exciter field 343 1 Diode bridge assembly
91 4 Field fixing screw 347 1 Surge suppressor Varistor
98 3 Corner plate 349 1 O ring seal
100 1 Exciter armature
 Your turn to doodle.

L1
AVR
L2
L3
N

EXCITER
ROTOR

MAIN ROTOR

EXCITER
MAIN STATOR RECTIFIER FIELD
 How it should look.

L1
L2
AVR
L3
N

MAIN ROTOR EXCITER

ROTOR

MAIN STATOR RECTIFIER EXCITER

FIELD
Alternator Labelling.

L L 2 0 1 4 H
Core Length
Manufacturer:
L = Leroy Somer
Number of Poles

Excitation:
Engine:
1 = Shunt
L= Perkins
2 = AREP
A = Li
Lister
t 3 Phase
Ph
3 = PMG
B = Lister 1 Phase

Alternator Series: Issue:

1 = 1000 0 = First issue
2 = 2000
etc.
ALTERNATOR MODEL / SPECIFICATIONS.
SPECIFICATIONS

Genset Alternator
30 KVA LL1014Q
44 KVA LL2014B
50 KVA LL2014D
65 KVA LL2014H
77 KVA LL2014J
100 KVA
A LL3014B
110 KVA LL3014B
150
0 KVA
A LL3014F
30 4
ALTERNATOR MODEL / SPECIFICATIONS.

Genset Alternator
175 KVA LL3014H
188 KVA LL3014H
200 KVA LL5014F
ALTERNATOR PRINCIPLE

STATOR
WINDING

ROTOR
WINDING
ALTERNATOR PRINCIPLE
EXCITER FIELD
RECTIFIERS
STATOR
WINDING

ROTOR
WINDING

DIRECT ALTERNATING
CURRENT CURRENT
SHUNT PRINCIPLE
EXCITER FIELD
STATOR RECTIFIERS
WINDING

ROTOR
WINDING

AVR

DIRECT ALTERNATING
CURRENT CURRENT
SHUNT + PMG PRINCIPLE
EXCITER FIELD
RECTIFIERS P.M.G.
STATOR
WINDING

ROTOR
WINDING
A.V.R.

ALTERNATING DIRECT
CURRENT CURRENT
PMG
290 Housing
p
291 Adaptation shaft
292 Rotor magnets
293 Stator
294 Fixing screw
295 Tie rod
296 Washer & nut
297 E
Endd plate
l t
PMG

5 TYPES PMG 1 2000-3000 Series R438

PMG 2 5000 6000 Series R448
5000-6000
PMG 3 7000 Series R448
PMG 4 8000-8100 Series R449
AREP fitted as standard to 8000&9000
( wires need isolated if fitting PMG )

ADAPTATION ON A SHUNT MACHINE 2000-3000

- REPLACEMENT OF R 230 BY R 438
- MODIFICATION OF CONNECTIONS (WIRING SUPPLIED)
- EXCITER FIELD RECONNECTION(SERIES TO PARR.)
- MECHANICAL FITTING OF PMG
PMG
SERIES CONNECTION PARALLEL CONNECTION

6- 6-

R230 R438

EXCITER FIELD 5+ EXCITER FIELD 5+

SHUNT EXCITATION PMG/AREP EXCITATION

Only applicable to the 2000/3000 Series.

14
X2
Z1 15 PMG
AVR X1
Z2 16
E+
E-
6- 5+
EXCITER FIELD

AVR connection for PMG.

AREP PRINCIPLE
EXCITER FIELD
STATOR RECTIFIERS
WINDING

ROTOR
WINDING

AVR

ALTERNATING DIRECT
CURRENT CURRENT
Auxiliary winding principle.

H1----Delivers a voltage to the exciter, proportional to the

output voltage ( wound in on top of the red phase windings of
th main
the i stator).
t t )

H3----Delivers a voltage
g to the exciter field, proportional to the
output current ( wound in on top of the blue phase windings of
the main stator).
 EXCITATION SYSTEMS
SHUNT + PMG AREP SHUNT

High starting High starting

capacity capacity

Short-circuit Short-circuit Self p

protected
ADVANTAGES capability capability against short circuit

Permanent
No extra length No extra length
Magnetism
g

Extra No short- circuit

Specific winding capabilit
capability
l
length
th

High number Low starting

Small added cost
of components capacity
DISADVANTAGES

Added cost
Sensitive to
distorting loads
OVERLOAD CHARACTERISTIC
SHUNT CHARACTERISTIC
( or auxiliary winding H1/ AREP)
VOLTAGE (V)
AREP/ PMG CHARACTERISTIC

UN AREP SERIES CHARACTERISTIC

( Auxiliary winding H3/ AREP)
SUSTAINED
VOLTAGE DIP

LOAD %
100% 200% 300%

LOW OVERLOAD HIGH OVERLOAD - SHORT CIRCUIT

 OVERLOAD

OVERLOAD HIGHER TEMPERATURE RISE

PERMISSIBLE OVERLOADS ( NOT DANGEROUS FOR THE ALTERNATOR )

DURATION 1H 30’ 15’ 5’ 2’ 30” 10” 3”

OVERLOAD
O O 10%
0% 11%
% 14%
% 25%
5% 50% 100%
00% 200%
00% S
S.C,
C, 3 PH

Each running with overload must be followed by a running

at the nominal rating during at least 1 hour or 10 minutes without load
SSHUNT
UN or AREP or PMG
MG ?
WHEN TO CHOOSE SHUNT ?
- SINGLE CIRCUIT INSTALLATION
- POWER CUT ACCEPTABLE
- SELF PROTECTION OF THE ALTERNATOR.

WHEN TO CHOOSE AREP OR PMG ?

- WHOLE INSTALLATION WITH SEVERAL CIRCUITS
- POWER CUT FORBIDDEN ( Hospitals, UPS etc.)
- HIGH RATE OF DISTORTING LOADS
LOADS.
- STARTING OF A BIG MOTOR
- AREP MINIMUM LENGTH REQUIRED
-PMG
PMG EXISTING SHUNT MACHINE TO BE UPGRADED

AREP / PMG ADVANTAGES COMPARED WITH SHUNT

- THE SHORT CIRCUIT CAPABILITY THAT ENABLES A SELECTIVE
PROTECTION IN CASE OF OVERLOAD OR SHORT CIRCUIT
ON AN INSTALLATION.
 Excitation: Series & AVR allocation.
Self-Excited ( Shunt ):
1000,2000,3000, Series AVR R230A
5000, 6000 Series AVR R448
8100,9100 Series AVR 449

PMG Excited:
1000 Series Not Available
2000,3000 Series AVR R438
5000,6000,7000 Series AVR R448
8100,9100 Series AVR R449

AREP Excited:
1000,2000,3000
1000 2000 3000 Series
S i AVR R438
5000,6000,7000 Series AVR R448
8000,9000 Series AVR R449

All AVR’s provide voltage regulation of +/- 0.5%.

THE 4 TYPES OF LEROY SOMER AVR
AVR’s.
s.

R230

R438 R448 & R449

AVR R 230
SHUNT EXCITATION R 230

50/60H CONNECTION
50/60Hz

EXCITOR FIELD CONNECTION FOR

CONNECTION EXTERNAL
POTENTIOMETER

UNDERSPEED
VOLTAGE SENSING

STABILITY ADJUSTMENT

FUSE VOLTAGE
ADJUSTMENT
AVR
V R 230
0
 AVR R 230
SHUNT EXCITATION
Knee Point
VOLTAGE REGULATION ± 0.5%
0 5% Voltage 48Hz 57.5Hz

VOLTAGE DETECTION 95V TO 140 V 100%

RESPONSE TIME : 500 MS 50Hz

50 / 60 HZ
60Hz
UNDERSPEED PROTECTION

OPTION : REMOTE POTENTIOMETER

Frequency

THE BEST AVR 50Hz 60Hz HZ

FOR
BASIC USE
 AVR CHARACTERISTICS R 438

AREP/PMG EXCITATION R 438

VOLTAGE ADJUSTMENT ± 5% STABILITY ADJUSTMENT LOW SPEED PROTECTION & LAM

SECONDARY CONNECTOR
MAXIMUM EXCITATION
FOR EXTENSION MODULES
CURRENT & S/C LEVEL
- three phase sensing
ADJUSTMENT
- paralleling

RESPONSE TIME SELECTION

Avoids speed oscillation of the
engine 50/60Hz CONNECTION

DROOP ADJUSTMENT LAM SELECTION

FOR ALTERNATOR
PARALLELING

FUSE

ISOLATING 3 POSSIBILITIES OF VOLTAGE

TRANSFORMER DETECTION
from 95 to 520 V - 1 or 2 PH sensing
 AVR R 438
AREP / PMG EXCITATION

VOLTAGE REGULATION ± 0.5%

Knee Point
Voltage 48Hz 57.5Hz
VOLTAGE DETECTION CHANGEABLE
FROM 95V- 520V. 100%

RESPONSE TIME : 300 MS OR 1 S

50Hz

UNDERSPEED PROTECTION
60Hz
50 / 60 HZ

NUMEROUS OTHER BUILT- IN FUNCTIONS

Frequency
- LAM ... 0
50Hz 60Hz HZ

THE AVR FOR

DEMANDING APPLICATIONS
R 438 AUTOMATIC VOLTAGE REGULATION

Optional modules

R 726 Paralleling with mains

3 functions
f ti
Some available options.

Th
Three Phase
Ph Sensing
S i unit
it EMI Suppresser
R731
 AVR CHARACTERISTICS
AREP/SHUNT/PMG EXCITATION R 448 & 449

50/60Hz CONNECTION
MAXIMUM EXCITATION
CURRENT & S/C LEVEL FUSE
ADJUSTMENT

LAM SELECTION
LOW SPEED PROTECTION & LAM

RESPONSE TIME SELECTION

Avoids speed oscillation of the 3 POSSIBILITIES OF VOLTAGE
engine DETECTION
from 95 to 520 V - 1 or 2 PH sensing

STABILITY ADJUSTMENT

ISOLATING
TRANSFORMER
VOLTAGE ADJUSTMENT ± 5%

SECONDARY CONNECTOR DROOP ADJUSTMENT

FOR EXTENSION MODULES FOR ALTERNATOR
- three phase sensing PARALLELING
- paralleling
 AVR R 448 & 449
SHUNT / AREP / PMG EXCITATION

VOLTAGE REGULATION ± 0.5%

Knee Point
Voltage 48Hz 57.5Hz
VOLTAGE DETECTION CHANGEABLE
FROM 95V - 520V.
%
100%

RESPONSE TIME : 300 MS OR 1 S

50Hz
UNDERSPEED PROTECTION

50 / 60 HZ 60Hz

NUMEROUS OTHER BUILT- IN FUNCTIONS

Frequency
- LAM ... 0

50Hz 60Hz HZ

THE AVR FOR

DEMANDING APPLICATIONS
R 448 & 449 AUTOMATIC VOLTAGE
REGULATION

Optional modules

R 726 Paralleling with mains

3 functions
RANGE- 4 POLE
RANGE
REGULATION CONFIGURATIONS / OPTIONS

REMOTE PF REG. VLT. 3P SENS.

AVR LAM CT
POT. R 726 MAT. R 731
PAR.
R 726
R 230 option NO NO NO NO NO
SHUNT
Option option STD opt option
opt. ti option
ti option
ti
R 448
R 438
AREP R 448 option STD opt option
opt. option option
R 449

SHUNT R 438
+ option STD opt. option option option
R 448
PMG R 449
LOAD ACCEPTANCE CAPACITY
R 438 / R 448 / R 449 FOR AREP EXCITATION

Situation : 100 % load is applied in

one step on turbocharged engine set CURRENT

Speed or Speed or
frequency frequency

• The engine stops

• The engine keeps
100 % load on running
• No load acceptance module
• Load acceptance module
LAM EFFECT ON ENGINE SPEED.
SPEED

11
1.1
Y per unitt

With LAM
1.0
EQUENCY

0.9 Soft
loading
SPEED or FRE

08
0.8
Without LAM

0.7

Same
0,3 sec
0.6 step delay
loading

Time 0 0,5 1 1,5 2 2,5 3 seconds

TIME
LAM EFFECT ON VOLTAGE

Overshoots
Without LAM
1.1

1.0
oltage perr unit

09
0.9
L
Saturation of generator
0.8
LAM action
Vo

0.7 T
Voltage dips
S : Subtransient
Delay T : Transient
0.6
0 3 sec
0,3 L : Steady (LAM)

S
Time 0 0,5 1 1,5 2 2,5 3 seconds

TIME
 ALTERNATOR RATINGS
CONTINUOUS POWER
Continuous operation at nominal constant load
unlimited number of hours / year
Cogeneration / Marine...
g S1/ 40°C - class H or F
Alternator rating

PRIME POWER
Continuous operation at variable load (average load at 70 % of the nominal load )
Unlimited number of hours/year .
Industry. Public works...
Alternator rating S1 40°C - Class H.
Load capability .

STAND BY
Maximum rating allowed during 500 H/year
((with
ith a maximum
i off 300 hours
h in
i continuous
ti running).
i )
Alternator rating stand - by duty 27°C.
FREQUENCY
FREQUENCY : (Hz) = Speed x Pairs of poles
60

MAIN FREQUENCIES :

50 Hz : EUROPE, AFRICA, PART OF ASIA, PART OF SOUTH AMERICA.

60 Hz : NORTH AMERICA, PART OF ASIA, PART OF SOUTH AMERICA.

400H : AIRPORTS
400Hz
ALTERNATOR SPEED
SPEED IN R.P.M.

POLE 2P 4P 6P 8P 10P 12P 14P 16P

50 Hz 3000 1500 1000 750 600 500 428 375

60 Hz 3600 1800 1200 900 720 600 514 450

DIRECTION OF ROTATION

STANDARD : CLOCKWISE LOOKING FROM THE DRIVE END

 POWER FACTOR
kW

CAPACITIVE INDUCTIVE

kVA

kVar

kW = ACTIVE POWER (REAL)

kVA = POWER ( APPARENT)
kV AR = REACTIVE POWER ( REACTIVE )
INDUCTIVE P.F. = INDUCTIVE LOAD, ISYNCHRONOUS MOTOR, TRANSFORMER ...
(CURRENT LAGS THE VOLTAGE)
CAPACITIVE POWER FACTOR : FLUORESCENT LIGHT, CAPACITOR ...
(CURRENT LEADS THE VOLTAGE)
 2/3 PITCH WINDING
NOTE :
A 2/3 pitch winding eliminates all triplen harmonics (3, 6, 9, etc ...)
which create a circulating current in the neutral and distort
the waveform.

When is a 2/3 pitch winding needed ?

A 2/3 pitch winding is generally used for the following reasons :

- Single phase loads sensitive to distortion
(single phase rectifiers, gas discharge lighting,...)
-Paralleling
Paralleling
- with other alternators when neutrals are connected
- with the main network when neutral is distributed
- Fitted
Fi d as standard.
d d
 TYPICALLY A MAIN STATOR WILL
CONSIST OF 9 WINDING ENTRIES
AT FULL PITCH----THEREFORE THERE FULL PITCH
SHOULD BE 6 AT 2/3 PITCH.
2/3 PITCH

PHASE WINDING ENTRY

THIS IS WHERE A PHASE WINDING

WILL ENTER THE MAIN STATOR
THEN EXIT AT 2/3 PITCH.
 VOLTAGE
12 WIRE RECONNECTABLE MACHINE
EXAMPLE: STANDARD WINDING N° 6 - 3 PHASE/ 2/3 PITCH.

Phase U Phase U
220V to 240V/50Hz 110V to 120V/50Hz
or or
254V to 277V/60Hz 127V to 138V/60Hz
Phase/Neutral Phase/Neutral

Phase W Phase V Phase W Phase V

380V to 415V/50Hz
or 190V to 208V/50Hz
440V to 480V/60Hz or
between phases 220V to 240V/60Hz
between phases

SERIES STAR CONNECTION PARALLEL STAR CONNECTION

 VOLTAGE
12 WIRE RECONNECTABLE MACHINE
EXAMPLE: STANDARD WINDING N° 6 - 3 PHASE/ 2/3 PITCH.

Phase U Phase U

Phase W Phase V Phase W Phase V

220V to 240V/50Hz 110V to 120V/50Hz
or or
240V/60Hz 120V /60Hz
between phases between phases

SERIES DELTA CONNECTION PARALLEL DELTA CONNECTION

 VOLTAGE
12 WIRE RECONNECTABLE MACHINE
EXAMPLE: STANDARD WINDING N° 6 - SINGLE PHASE

L
L L L
M Phase Phase
Phase Phase

220V to 240V/50Hz 220V to 240V/50Hz

or or
240V/60Hz 240V/60Hz
between phases between phases

Voltage LM=1/2voltage LL Voltage LM=1/2 voltage LL

(FF) CONNECTION CONNECTION ZIG - ZAG (G)

( NOT RECOMMENDED)
Fault finding on the
Alternator.
Mechanical Defects.
Defects
Electrical Defects.
Defects
Electrical Defects.
Defects
 Fault finding on the
Main Stator.

L1 L1
100 120
L2 140 L2 120
80 120
L3 L3

L1
70
L2 100
90
L3

Inconsistent Voltage readings across the three phases, is a good sign that the
Main stator windings have gone.
Fault finding the Exciter Stator
and the AVR.

DIRECT ALTERNATING
CURRENT CURRENT

Putting a separate DC supply on to the exciter field allows you to determine whether or not
the AVR, Exciter field or diodes have gone.Plus it can be used to Re-excite the Alternator
a diode needs to be fitted on both exciter field wires.
Testing the diodes.
diodes

MULTIMETER MULTIMETER

MORE THAN LESS THAN

10,000 OHMS 100 OHMS
Fault Finding- Testing the Resistance of the Main
Rotor using a 6V battery.

AVO meter on 10amp +

range or DC ammeter.

6V

Rotor Resistance = 6
AMPS
If y
you have a Multi-meter y
you do not have to do the above calculation.Then y
you refer
to the manual for the resistance.
Insulation Test.

1.Minimum acceptable value of insulation to earth is one Megohm.

2 Th AVR MUST be
2.The b disconnected
di t d before
b f meggering
i the
th windings.
i di

3.Megger the :- Main stator

Main rotor
Exciter stator
Exciter rotor

Meggering is only necessary if the generator has become wet or has not been
used for a long time.
Use a 500V insulation tester.
Questions & Answers.
Answers

“Remember, a teacher hasn’t taught

“Remember
until the student has learnt”.