J

Over-heat of Resistor Module (ECM)

Fanuc · [PDF] Fanuc Macro B.pdf CNCTar

What does J mean?

The Energy Charge Module's (ECM) Resistor Module has detected an over-heat condition via its built-in thermostat. This indicates excessive energy dissipation, possibly due to continuous regeneration, high ambient temperature, or a fault in the cooling of the resistor module, leading to potential damage.

Repair Steps

  1. 1

    Immediately stop the machine using the emergency stop button and open the external Main Circuit Contactor (MCC) of the Power supply.

  2. 2

    Check the ambient temperature around the Resistor Module (A06B-6158-H030); ensure it is within the specified operating range (0 to 55°C).

  3. 3

    Verify proper ventilation and airflow around the Resistor Module; clear any obstructions preventing heat dissipation.

  4. 4

    Inspect the Resistor Module for any dust or debris accumulation on its surface that could impede cooling efficiency.

  5. 5

    Review the machine's operational cycle to identify if prolonged or frequent regenerative braking is occurring, potentially exceeding the resistor's continuous power rating.

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Verified technical data. Last updated: March 2026
Source: [PDF] Fanuc Macro B.pdf CNCTar