01 ALARM — MOTOR OVERHEAT / INPUT CIRCUIT OVERCURRENT

Identify which module indicates the '01' alarm. If it is on the Power Supply (PSM/Converter), disconnect the power, wait for the DC link to discharge, and check the DC link wiring for short circuits. If a short circuit or IGBT failure is found, replace the Power Supply module.

If the '01' alarm is on the Spindle Amplifier and the motor is physically hot, inspect the motor cooling fan. Clean the heat sink and fan. If the fan has stopped operating, replace the motor cooling fan.

Evaluate the machining cycle. If the motor is subjected to frequent acceleration/deceleration or a continuous heavy cutting load, modify the CNC program to reduce the load, increase the acceleration/deceleration time constant, or add stop time to cool the motor.

If the '01' alarm appears when the motor is completely cold, inspect the spindle motor feedback cable and connectors for coolant ingress, broken wires, or loose connections. Clean or replace the feedback cable if any damage is found.

Verify the motor-specific parameters in the CNC (such as parameter No. 4134). If the parameters do not match the motor specifications, correct them according to the FANUC parameter manual.

If the cables and parameters are correct but a cold motor still generates the alarm, the motor's internal thermostat or the amplifier's control printed circuit board is defective. Replace the Spindle Amplifier control printed circuit board or the spindle motor.

If none of the above steps resolved the alarm, contact an authorized FANUC service representative.