TROUBLE SHOOTING
28
November 2010 / M-SQ20 / 25 / EN
PROBLEM CAUSE
SOLUTION
•
Rotor diode broken.
Check the diode in the rotor (see special
procedures). The M-SQ20 / 25 has one diode
block/rectifier unit.
Generator output voltage too
low when no load is on it (less
than 225V between phase and
neutral).
•
Engine is not reaching the rated RPM.
See special procedures to readjust RPM.
•
Faulty AVR. When slightly too low,
adjustment could be necessary
Try to readjust AVR. Check by independent
excitation if the problem is in the AVR or in the
windings and replace AVR if necessary (see
special procedures).
•
Defective diode
Check the diode in the rotor (see special
procedures). The M-SQ20 / 25 has one diode
block/rectifier unit.
Generator output voltage too
low under load (less than 225V).
In no load condition it is OK
•
When applying 3 phase: an
unbalanced load; check the voltage of
the other phases. When the voltages
are different this is caused by an
unbalanced load.
Bring load in balance. When slightly out of
balance, remove the sense wires to the phase
with the highest load and check if the voltage
on the other phases is not too high.
•
Engine is not reaching the rated RPM.
Possibly too much load or engine
problems (lack of fuel)
Switch off a load; (part off) consumers
See to engine RPM problems
•
Faulty AVR or readjustment necessary Try to readjust the voltage
Check by independent excitation if the problem
is in the AVR or in the windings and replace
AVR if necessary (see special procedures).
Generator output voltage too
high, (more than 235V)
•
Over-energising due to defective AVR
or wrong AVR setting
Check AVR, readjust and replace if necessary
capacitor specification and replace AVR if
necessary (see special procedures)..
Generator output voltage too
high, (more than 235V)
In no load condition it is OK
•
Unbalanced load
Bring load in balance.
When slightly out of balance, remove the
sense wires to the phase with the highest load
and check if the voltage on the other phases is
not too low.
Generator voltage fluctuates.
•
Disturbances on the electrical system/
user side.
Check if electrical load is fluctuating
•
AVR reacts on fluctuating load
Readjust the stability setting on the AVR
trimmer
“ST”
•
Engine runs irregularly.
When engine runs irregularly see section:
"Engine runs irregularly" at the “Engine faults”
paragraph.
Generator is not able to start an
electric motor
If the generator is unable to supply
enough power to start an AC electric
motor, this is usually because this motor
draws too much current during starting
As the alternator is very much under-
rated the problem will appear by the
engine RPM collapsing
Check the electric motor’s current draw
required for starting. This should not exceed
the rated generator output current. This could
be remedied by using a "soft-start". Inquire at
your nearest WhisperPower dealer or directly
at the manufacturer, WhisperPower in the
Netherlands.
5.2 Engine
faults
CAUTION!
Remove 3 Amp. fuse in the control panel
while working on the generator to prevent the
engine from starting.
5.2.1 General
Most electrical problems relating to Voltage or Frequency
are due to wrong engine speed.
Note that RPM and Hz are basically the same.
Use the problem solving table to find the cause of a wrong
engine speed. When there is no obvious cause one can
adjust the RPM (see special procedures).
When the engine is not cranking well, starting problems
almost always originate from battery problems or poor
battery cable connections.
