12
INSTALLATION AND MAINTENANCE
LSA 46.2 / 47.1 - 4 POLE
ALTERNATORS
INSTALLATION
Ref. 2981 GB - 4.33/b - 07.02
LEROY-SOMER
3.5.1 - R 448 settings
a) Initial potentiometer settings (see table below)
- Remote voltage adjustment potentiometer : centre (strap
ST4 removed).
Adjustments in standalone operation
b) Install a D.C. analogue voltmeter (needle dial) cal. 100V on
terminals E+, E- and an A.C. voltmeter cal 300 - 500 or 1000V
on the alternator output terminals.
c) Make sure that strap ST3 is positioned on the desired
frequency (50 or 60 Hz).
d) Voltage potentiometer P2 at minimum, fully anti-clockwise.
e) Turn the V/Hz potentiometer P4 fully clockwise.
f) Stability potentiometer P3 to approximately 1/3
anti-clockwise turn.
g) Start the engine and set its speed to a frequency of 48 Hz
for 50 Hz, or 58 for 60 Hz.
h) Set the output voltage to the desired value using P2.
- Rated voltage UN for solo operation
(eg. 400 V)
- Or UN + 2 to 4% for parallel operation with C.T. (eg. 410 V)
If the voltage oscillates, use P3 to make adjustments (try both
directions) observing the voltage between E+ and E- (approx.
10V D.C.). The best response times are obtained at the limit
of the instability. If no stable position can be obtained, try
cutting or replacing strap ST2 (normal/fast).
i) Check LAM operation : ST5 closed.
j) Turn potentiometer P4 slowly anti-clockwise until there is a
significant voltage drop (approximately 15%)
k) Vary the frequency (speed) around 48 or 58 Hz according
to the operating frequency, and check the change in voltage
from that observed previously (approximately 15%).
l) Readjust the speed of the unit to its rated no-load value.
Adjustments in parallel operation
Before any intervention on the alternator, make
sure that the speed droop is identical for all
engines.
m) Preset for parallel operation (with C.T. connected to S1,
S2 on connector J2)
- Potentiometer P1 (quadrature droop) in centre position.
Apply the rated load (cos Ø = 0.8 inductive).
The voltage should drop by 2 to 3%. If it increases, swap the
2 incoming wires from the C.T. secondary.
n) The no-load voltages should be identical for all the
alternators intended to run in parallel.
- Couple the machines in parallel.
- By adjusting the speed, try to obtain 0 KW
power exchange.
- By altering the voltage setting P2 or Rhe on one of the
machines, try to cancel (or minimise) the current circulating
between the machines.
From now on, do not touch the voltage settings.
o) Apply the available load (the setting is only correct if a
reactive load is available)
- By altering the speed, equalise the KW (or divide the rated
power of the units proportionally)
- By altering the quadrature droop potentiometer P1, equalise
or divide the currents.
Action
Factory setting
Pot.
P2
P3
P4
P1
P5
10 A
maximum
400V - 50 Hz
(Input
0 - 380 V)
Not set
(centre position)
If ST3 = 50 Hz
(factory) = 48 Hz
If ST3 = 60 Hz
(factory) = 58 Hz
Not set
(fully anti-
clockwise)
Excitation ceiling
Limit of excitation and
short-circuit current,
minimum fully anti-clockwise
Voltage quadrature droop
(// operation with C.T.)
- 0 quadrature droop fully
anti-clockwise.
Voltage
minimum fully anti-clockwise
Stability
Threshold/LAM or U/F
Underspeed protection
and "LAM" trip threshold
Maximum frequency fully
anti-clockwise
WARNING
ARNING
