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5 TROUBLE SHOOTING
5.1
ALTERNATOR/ ELECTRICAL FAULTS
Beware of parts which are live!
Remove 3 Amp. Fuse in the control panel
while working on the generator to prevent the
engine from starting
5.1.1
General
If any problem should occur, check basic conditions and
examine all external wiring, switch gear and circuit
breakers. Also check if measuring instruments give the
correct value. If in doubt, measure directly on the
alternator terminals with an independent instrument.
5.1.2
Trouble shooting table
PROBLEM
No output (Voltage) at all
Generator output voltage too
low when no load is on it (less
than 210V).
Generator output voltage too
low under load (less than 210V).
In no load condition it is ok
Generator voltage too high,
(more than 245V)
EN / W-SC3 Mobile / January 2011
CAUSE
• Circuit breaker "off" or faulty fuse
• Low engine RPM.
• Loss of residual magnetism.
• Capacitor loose or broken.
• Rotor diodes broken.
• No load at all or very low load.
• Engine is not reaching the rated RPM.
• Defective capacitor.
• Defective diode (one of the two)
• Generator is overloaded.
• Engine is not reaching the rated RPM.
• Defective capacitor
• Engine is running too fast (RPM too
high).
• Over-energising
due
capacitors
• Presence of a strong capacitive load
(leading power factor)
This should only be carried out by an experienced
electrician.
Check if the engine is running correctly at 3000 (50 Hz)
RPM according to its settings and does as well under load.
A RPM drop of 5% at full load is acceptable. There-fore a
no load setting should be at 3150 RPM = 52.5 Hz or 3750
RPM = 62.5 Hz. Under no circumstances should the RPM
under full load be below 2940 RPM = 49 Hz or 3540 = 59
Hz.
When the problem is in the RPM refer to the engine fault
finding paragraph.
Digital Diesel Control system will help to indicate failures
and display causes.
SOLUTION
Check switches and fuses and measure
directly on the alternator to exclude external
causes.
Check the engine RPM and adjust (refer to
special procedures).
Check the residual magnetism and flash the
alternator (refer to special procedures).
Check by independent excitation if the problem
is in the capacitor or in the windings.
Check the diodes in the rotor (refer to special
procedures) The W-SC3 has two diodes in the
rotor. It happens very rarely that both are
broken. When only one diode is broken the
voltage will be low but will not varnish
completely.
Switch on a load and check voltage.
Refer to special procedures to readjust RPM.
Check capacitor and replace if necessary
(refer to special procedures).
Check the diodes in the rotor and replace
(refer to special procedures).
Switch off a load; (part off) consumers.
Refer to engine RPM problems
Check capacitor and replace if necessary
(refer to special procedures).
Check engine speed and adjust (refer to
special (more than 245V).procedures).
Check capacitor specification and replace
to
defective
capacitors if necessary.
Compensate for this capacity and seek for
experts advice.
TROUBLE SHOOTING
21
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Troubleshooting
