Yaskawa YASNAC PC NC Maintenance Manual - Manual (Page 177)

PC NC Maintenance Manual The VS-626M5
4-156
Motor Faults And Corrective Actions
If any of the following faults occurs in the motor, check the cause and pro-
vide the relevant corrective actions.
Table 4.38: Motor Faults and Corrective Actions
Fault Cause Corrective Action
Motor does not rotate. Protective function has been acti-
vated. Check fault number. and carry out appropriate steps.
Converter main circuit power is not
turn ON. Turn ON power supply.
Check supply voltage.
Inverter output disconnection,
improper connection Check the wiring between inverter and motor.
Control signal does not function. Check sequence input signal on operation status dis-
play (U1-09) (RDY, EMG, FWD and REV).
Check if speed reference is input or not on operation
status display (U1-02).
Torque limiting Check whether external torque limit signals TLL or
TLH is input on operation status display (U1-09).
Motor winding wire disconnection Check resistance between motor terminals (a circuit
tester necessary).
Replace the motor.
Motor fault (rotor and stator rub
together, broken bearing) Check motor shaft rotation manually.
Replace the motor.
Control PC board fault Replace the control PC board.
Motor rotates slowly or
vibrates with no rota-
tion. Inverter output disconnection,
improper connection Check the wiring between inverter and motor.
Encoder signal line disconnection,
improper connection, loose connec-
tor Check the wiring of encoder signal line.
Motor encoder fault Check for abnormal changes in motor speed on
speedometer or operation status display (U1-01).
Replace the encoder or the motor.
Speed reference signal disconnec-
tion, improper connection Check the wiring of speed reference signal.
Torque limiting Check whether external torque limit signals TLL or
TLH is input on operation status display (U1-09).
Control PC board fault Replace the control PC board.
Motor rotates in
reverse direction. Improper connection of inverter out-
put or motor encoder signal line Check the wiring according to the connection dia-
gram.