Leroy Somer LSA 49.1 4P Manuel D'utilisation Et D'entretien page 37

LEROY-SOMER
3.5.2 - Max. excitation setting (excitation
ceiling)
Max. excitation
ST3
X2
P5
50Hz 60Hz
Z1
X1
P4
Z2
E+
R 448
P3
E-
0V
110 V
P2
220V
ST4
380V
Voltage
- static adjustment of the current limit , potentiometer P5 (fuse
rating : 8 A - 10 seconds) Fig 15.
The maximum factory setting corresponds to that of the
excitation current required to obtain a 3-phase short-circuit
current of approximately 3 IN at 50 Hz for industrial power,
unless otherwise specified(*).
A static method can be used to reduce this value or adapt the
Isc to the actual operating power (derated machine), which is
safer for the alternator and the installation. Disconnect power
supply wires X1,X2 and Z1,Z2 and the voltage reference
(0-110V-220V-380V) on the alternator.
Connect the mains power supply (200-240V) as indicated
(X1,X2) : 120V). Install a 10A D.C. ammeter in series with the
exciter field. Turn P5 fully anti-clockwise and activate the
power supply. If there is no output current from the AVR, turn
potentiometer P2 (voltage) clockwise until the ammeter
indicates a stable current. Switch the power supply off, then
on again, turn P5 clockwise until the required max. current is
obtained (no more than 10 A).
Checking the internal protection :
Open switch (D) : the excitation current should increase to its
preset ceiling, remain at that level for ≥ 10 seconds and then
drop to < 1A.
To reset, switch off the power supply by opening switch (A).
Note : After setting the excitation ceiling as described, adjust
the voltage again (see section 3.5.2).
(*): In some countries it is a legal requirement to have a
short-circuit current, so as to offer discriminating protection.
INSTALLATION AND MAINTENANCE
LSA 49.1 4P
ALTERNATORS
INSTALLATION
depending on the mains frequency
100V...140V
A
Field
- +
~ 10 ohms
A
10A DC
D
110/220/380V
3.5.3 - Special type of use
- Field weakening
X2
Z1
X1
Z2
E+
The exciter is switched off by disconnecting the AVR power
supply (1 wire on each auxiliary winding) - contact rating 16 A
- 250V A.C.
Connection is identical for resetting the AVR internal
protection.
- Field forcing
X2
Z1
X1
Z2
E+
E-
Forced excitation
B Volt
Applications
Guaranteed voltage build-up
Parallel operation, de-energized
Parallel operation, at standstill
Frequency starting
Sustained voltage on overload
Ref. 3007 GB - 4.33/a - 10.00
AREP / PMG
(400V - 10A) Diode
+
-
t
Battery (B Volt)
~ 10 ohms
Exciter field
t
Time
B volts Time t
12 (1A) 1 - 2 s
12 (1A) 1 - 2 s
24 (2A) 5 - 10 s
48 (4A) 5 - 10 s
48 (4A) 5 - 10 s
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