I²xt overload advance warning

What does OC8 mean?

This is an advance warning for a potential I²xt overload, indicating frequent and prolonged acceleration processes with motor overcurrent or permanent motor overload with Imotor > Irmotor. It suggests that conditions are approaching a trip threshold.

• Sustained operation of the motor above its nominal rated current (e.g., 90-100% of C0203) without tripping the drive immediately.
• Repetitive acceleration and deceleration cycles where the motor current briefly exceeds nominal, gradually accumulating thermal stress.
• Increasing mechanical friction or an impending mechanical jam in the driven system, subtly increasing motor load over time.
• Motor's cooling efficiency has degraded (e.g., partially clogged fan, dirt accumulation) reducing its ability to dissipate heat.
• Parameter C0171 (Motor I²xt overload warning limit) is set too conservatively, triggering the warning prematurely for the application.

Click steps to track your progress.

1. 1

   Monitor motor current (C0004) and motor temperature (C0005, if available) to identify the specific operating conditions that trigger the warning.

2. 2

   Inspect the mechanical system for signs of increased friction, worn bearings, or any other issues that could be increasing the motor's load.

3. 3

   Verify the integrity and cleanliness of the motor's cooling system (fan, heatsink fins) and the drive's heatsink.

4. 4

   Consider extending acceleration/deceleration ramp times (C0256, C0257) or reducing commanded speed/torque if dynamic loads are high.

5. 5

   If the warning is deemed too sensitive for the application, cautiously increase the I²xt overload warning limit (C0171) in small increments, while still ensuring motor protection.