Inverter overload

What does 9 mean?

The frequency converter has been operating at more than 100% overload for an excessive period and is about to trip. A warning is issued at 98% overload, and a trip (alarm) occurs at 100%. The frequency converter cannot be reset until the internal thermal counter drops below 90%.

• Motor operating at continuous current above its rated value due to sustained mechanical overload (e.g., clogged pump, seized bearing).
• Incorrect motor parameters programmed in the drive (e.g., P1-20 Motor Rated Current, P1-23 Motor Rated Power are too low).
• Motor size is too small for the application's required load, leading to continuous high current draw.
• Motor output cable impedance too high or cable length excessive, causing increased current draw for a given load.
• Drive cooling fan failure leading to insufficient cooling and subsequent derating of overload capacity.

Click steps to track your progress.

1. 1

   Measure the actual motor current (e.g., with clamp meter on U, V, or W output phases) and compare to motor nameplate and P1-20.

2. 2

   Verify the motor's mechanical load by manually turning the shaft (if possible) for unusual resistance or friction.

3. 3

   Cross-check all motor parameters in the drive (e.g., P1-20 to P1-25) against the motor nameplate data.

4. 4

   Inspect the drive's internal and external cooling fans for proper operation and ensure unobstructed air circulation.

5. 5

   Increase the drive's acceleration and deceleration ramp times (P3-41, P3-42) to reduce peak currents during transients.

6. 6

   Consider upsizing the motor or drive if continuous current remains above 95% of rated current under normal load.