Overcurrent Alarm

What does 412 mean?

An Over Current Alarm has been issued, indicating an excessively large current flow in the main circuit. This is a critical alarm that can result from incorrect motor parameters, short-circuits in the motor or power line, amplifier malfunction, or noise.

• Incorrect motor ID number set in parameter No.125.
• Current control parameters (No.70, 71, 72, 78, 79, 84, 85, 86, 87, 88, 89, 90, 99, 118, 119) are not set to standard values (see Appendix B).
• Short-circuit between ground and motor phases (U, V, or W).
• Short-circuit within the motor power line.
• Abnormal motor current waveform (not a normal sine wave) during acceleration or deceleration.
• Presence of noise in the motor current waveforms.
• Defective pulse coder, command cable, or internal hardware of the CNC.

1. 1

   Verify that parameter No.125 contains the correct motor ID number.

2. 2

   Check that current control parameters No.70, 71, 72, 78, 79, 84, 85, 86, 87, 88, 89, 90, 99, 118, 119 are set to their standard values (refer to Appendix B).

3. 3

   Disconnect the power line from the servo amplifier module connector. Release the emergency stop state. If the over-current alarm continues, replace the servo amplifier module.

4. 4

   If the alarm ceases, check the insulation resistance between the ground and each of the motor phases U, V, and W. If a short-circuit is detected, disconnect the power line from the motor connector and re-check motor insulation. If motor insulation is bad, replace the motor. If motor insulation is good, replace the power line.

5. 5

   Connect the power line. Observe the waveform of the motor current (IR, IS) during acceleration or deceleration. If the current does not exhibit a normal sine wave, replace the servo amplifier module.

6. 6

   If the motor current (IR, IS) waveforms include noise, implement shield ground connections or other noise reduction actions. If noise is not the cause, replace the servo amplifier module.