Electrolux W455 H Service Manual page 36

36
Undervoltages can be registered even during normal operation.
Consequently, a small number of registrations need not mean that there is
a fault in the motor control.
Measure:
• Check that the supply voltage is stable and never drops below nominal
voltage - 10%.
• Check that the fuses and cables are not faulty.
• Check the supply voltage in the network cabling and at the motor control
system in the machine.
Fault code 38, HIGH DC VOLTAGE
This fault code is generated by the motor control. The motor control reads
the voltage across the bulk capacitors (DCBUS voltage) continuously. If the
voltage becomes too high (= exceeds a certain limit), the motor control will
cut the current to the motor. Once the motor has stopped (= tacho sensor
indicates stationary motor), the motor control will check to see whether the
high DCBUS voltage remains. If this is the case, the "HIGH DC VOLTAGE"
fault code will be activated.
The reason for this fault code being activated can be high mains voltage
(e.g. power surge). Further information can be obtained by studying the
contents of "FC FAULT LOGGER":
• OVERVOLTAGE 2 (specifies how many times fault code 38 has been
active)
• OVERVOLTAGE 1 (specifies how many times the voltage limit has been
exceeded. The difference between overvoltage 1 and overvoltage 2 gives
the number of times overvoltage 1 has occurred without it being
confirmed when the motor has stopped).
• LAST FAULT CODE N/8 (shows the 8 latest fault codes)
Overvoltage registrations can also occur if there is a bad contact in the
tacho signal. Check also the following registers:
• TACHO CUT-OUT LOW RPM (number of short tacho interruptions
during wash rpm)
• TACHO CUT-OUT HIGH RPM (number of short tacho interruptions
during extraction rpm)
Action:
• Check the tacho cables if there are many registrations in the TACHO
CUT-OUT registers.
438 9047-81/02
Troubleshooting