Engine Faults; General - Whisper Power M-SQ27 User Manual

TROUBLESHOOTING
PROBLEM
Generator output voltage too
low when no load is on it (less
than 225V between phase and
neutral).
Generator output voltage too
low under load (less than
225V).
In no load condition it is OK
Generator output voltage too
high, (more than 235V)
Generator output voltage too
high, (more than 235V)
In no load condition it is OK
Generator voltage fluctuates.
Generator is not able to start
an electric motor
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.
CAUSE
• Engine is not reaching the rated RPM.
• Faulty AVR. When slightly too low,
adjustment could be necessary
• Defective diode
• When
applying 3
unbalanced load; check the voltage of
the other phases. When the voltages
are different this is caused by an
unbalanced load.
• Engine is not reaching the rated RPM.
Possibly too much load or engine
problems (lack of fuel)
• Faulty AVR or readjustment necessary
• Over-energising due to defective AVR
or wrong AVR setting
• Unbalanced load
• Disturbances on the electrical system/
user side.
• AVR reacts on fluctuating load
• Engine runs irregularly.
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
SOLUTION
See special procedures to readjust RPM.
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).
Check the diode in the rotor (see special
procedures). The M-SQ27 has one diode
block/rectifier unit.
Bring load in balance. When slightly out of
phase: an
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.
Switch off a load; (part off) consumers
See to engine RPM problems
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).
Check AVR, readjust and replace if
necessary capacitor specification and replace
AVR if necessary (see special procedures)..
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.
Check if electrical load is fluctuating
Readjust the stability setting on the AVR
trimmer "ST"
When engine runs irregularly see section:
"Engine runs irregularly" at the "Engine faults"
paragraph.
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.
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.
When the engine is cranking, well starting problems almost
always originate from lack of fuel or air bubbles in the fuel
pipes.
CAUTION!