Soga sincro FB4 BT, Use And Maintenance Manual

Page: 26 / 36

26 - FB BT - Giugno 2009 - Rev. 00
7.3 Troubleshooting
ELECTRICAL FAULTS
FAULT POSSIBLE REASON CHECK / REMIDY
NO VOLTAGE
Faulty AVR
•
Check the fuse
•
Replace the AVR
Faulty rotating rectifi er bridge AND/OR
surge suppressor (rif. 7)
•
Check rotating rectifi er bridge
Faulty stator exciter
•
Check if the stator exciter circuit is
open
Main winding fault
•
Check stator/rotor windings
resistances
•
Check stator/rotor windings insualtion
resistance
Demagnetized machine
•
Excite the alternator by applying a
6-12 volt current across the exciter
terminals for a second, respecting the
polarities. (engine is running)
Faulty rectifi er bridge (rif. 37)
•
Check rectifi er bridge
Broken connections
•
Check all connections
LOW
VOLTAGE/CURRENT
Reference voltage is not set at desired
value
•
Adjust voltage with potentiometer «V»
on the AVR;
Under-frequency protecton not properly
adjusted
•
Check / adjust, the value of under-
frequency protection (47Hz for 50Hz
nominal frequency)
Engine speed low
•
Check the engine speed(voltage
frequency)
Faulty AVR
•
Replace the AVR
HIGH
VOLTAGE/CURRENT
Reference voltage is not set at desired
value
•
Adjust voltage with potentiometer «V»
on the AVR
Sensing supply open circuit
•
Check the sensing connections
Faulty AVR
•
Replace the AVR
VOLTAGE/CURRENT
OSCILATIONS
AVR stability incorrectly set
•
Adjust stability with ST trimmer
Engine speed unstable
•
Check with the frequencymeter if there
are oscilations in engine speed
Faulty AVR
•
Replace the AVR
For more question contact Sincro After Sales Service.
ENGLISH