Yaskawa YASNAC PC NC Maintenance Manual - Manual (Page 69)

PC NC Maintenance Manual Chapter 4: Troubleshooting
4-48
AL-02:Ground fault
Error Contents The ground fault current in the inverter output side exceeded the
ground fault detection level (25% of the rated current of the transistor).
Detection Methods Add three-phase output current (Iu, Iv, Iw) detected by the current
detector. If this addition value exceeds the ground fault detection drive
level, the current is instantaneously intercepted, and the ground fault
detection signal is turned ON.
If the ground fault detection signal has been turned ON, the drive is
stopped and the alarm is displayed.
Cause and measures
AL-04:Main circuit open fuse line
Error Contents The main circuit fuse has fused.
Detection Methods Output to the control card formatting the main circuit open fuse line
signal by the gate driver (7CN-5). If the main circuit open fuse line sig-
nal has been turned ON, the current is intercepted and the alarm is dis-
played.
Cause and measures
Cause Measures
Ground fault Verify there is no short-circuit between inverter I/O ter-
minal and ground.
Insufficient insulation in the motor. Check the motor. Exchange the motor with a non-
defective one.
Control card fault Exchange unit (exchange control card)
Cause Measures
Main circuit fuse fusion Check the main circuit fuse continuity.
Repair the inverter (fuse and transistor)
Control card fault Exchange unit (exchange control card)