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ErrorLib — Industrial Fault Code Library

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oL4

Overtorque Detection 2

Yaskawa · GA500 Maintenance and Troubleshooting

What does oL4 mean?

This fault signifies a mechanical issue with the machine, such as a lock, or improperly set load parameters. The drive detects this fault if the output current surpasses the threshold defined by L6-05 for a period longer than L6-06. Ignoring this fault can lead to significant mechanical stress and potential equipment failure.

Common Causes

  • Sudden increase in load demand exceeding the motor's or drive's instantaneous torque capability.
  • Incorrectly configured Overtorque Detect Level 2 (L6-05) or Overtorque Detect Time 2 (L6-06).
  • Bearing failure or excessive friction within the driven equipment causing increased resistance to rotation.
  • Motor winding deterioration leading to reduced efficiency and increased current draw for a given torque.
  • Drive current sensor calibration drift or failure, providing inaccurate current readings.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    1. Adjust parameter L6-05 (Overtorque Detect Level 2) and L6-06 (Overtorque Detect Time 2) to match application transients.

  2. 2

    2. Measure motor current (e.g., using a clamp meter on output phase U) and compare it to the drive's display (U1-04).

  3. 3

    3. Disconnect the motor from the load and run it in no-load condition to check for internal motor issues.

  4. 4

    4. Inspect mechanical bearings and gears of the driven machine for excessive wear, lubricant loss, or damage.

  5. 5

    5. Ensure the motor's cooling fan is operating effectively, as overheating can reduce torque capability.

  6. 6

    6. Perform an encoder alignment check if using vector control, as misaligned feedback can cause overcurrent.

Browse all codes in this manual (60)
Verified technical data. Last updated: April 2026

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CECommunication Data ErrorCFControl FaultCP1Comparator 1 Limit Error
Source: Yaskawa GA500 Maintenance and Troubleshooting
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