- 86 -
Alternator troubleshooting
Symptom
Possible cause
Corrective action
Alternator gives 0 Volt
Blown fuse.
Replace fuse.
No residual voltage.
Excite the alternator by applying a 12V battery voltage with a 30
Ω
resistor in series on the + and - terminals of the electronic regulator,
respecting the polarities.
After being excited the alternator still
gives 0 Volt.
Connections are interrupted.
Check connection cables, measure winding resistances and compare
with values mentioned in the alternator manual.
Low voltage at no load
Voltage potentiometer out of setting.
Reset voltage.
Intervention of protection.
Check frequency/voltage regulator.
Winding failure.
Check windings.
High voltage at no load
Voltage potentiometer out of setting.
Reset voltage.
Failed regulator.
Substitute regulator.
Lower than rated voltage at load
Voltage potentiometer out of setting.
Reset voltage potentiometer.
Intervention by protection.
Current too high, power factor lower than 0.8; speed lower than 10%
of rated speed.
Failed regulator.
Substitute regulator.
Rotating bridge failure.
Check diodes, disconnect cables.
Higher than rated voltage at load
Voltage potentiometer out of setting.
Reset voltage potentiometer.
Failed regulator.
Substitute regulator.
Unstable voltage
Speed variation in engine.
Check regularity of rotation.
Regulator out of setting.
Regulate stability of regulator by acting on STABILITY
potentiometer.
Summary of Contents for QAS 500 Volvo S2A APP
Page 1: ...QAS 500 Volvo S2A APP Instruction Manual for AC Generators English...
Page 2: ......
Page 99: ...99 Circuit diagrams...
Page 112: ......
Page 113: ......
Page 114: ...Printed in Belgium 05 2009 2954 3870 00 www atlascopco com...