9.

Inverter: IPM alarm (M axis) or Overheat

Fanuc · Series 30i/31i/32i-MODEL B Plus

What does 9. mean?

An Intelligent Power Module (IPM) alarm has occurred for the M axis. This can indicate a short-circuit or ground fault in the power lead phases or motor winding phases, or an internal IPM failure. Additionally, it may signal an IPM overheat condition, often caused by the motor operating under harsh conditions or excessively high ambient temperatures. This fault implies a critical power module issue.

Common Causes

  • Short-circuit between power lead phases or ground fault in them
  • Short-circuit between motor winding phases or ground fault in them
  • The motor is being used under a harsh condition
  • The ambient temperature is high
  • Servo Amplifier failure

Repair Steps

  1. 1

    Measure insulation resistance of power lead phases to ground using a megohmmeter.

  2. 2

    Measure insulation resistance between motor winding phases and from each phase to ground.

  3. 3

    Assess the motor's operating conditions and load to ensure they are within specifications.

  4. 4

    Measure the ambient temperature around the inverter and confirm it is within specified environmental limits.

  5. 5

    If external electrical and environmental checks are good, replace the Servo Amplifier.

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Verified technical data. Last updated: March 2026
Source: Fanuc Series 30i/31i/32i-MODEL B Plus