Overload Motor

What does OLF mean?

The motor has experienced a sustained overload condition, drawing current above its rated value for an extended period. This can lead to severe motor overheating, insulation damage, and eventual motor failure.

• Sustained excessive mechanical load on the motor, causing prolonged current draw above its FLA (Full Load Amps).
• Incorrect motor thermal overload curve (e.g., P1-03) or motor service factor (e.g., P1-05) set too low in the soft starter parameters.
• Motor cooling fan failure or blocked motor cooling fins leading to reduced heat dissipation from the motor.
• High ambient temperature around the motor causing reduced thermal capacity and faster heating.
• Under-sized motor for the application's continuous load requirements, leading to chronic overload.

Click steps to track your progress.

1. 1

   1. Measure motor operating current on all three phases (U, V, W) with a clamp-on ammeter during steady-state operation; compare to motor nameplate FLA and soft starter setting (P1-01).

2. 2

   2. Inspect the driven mechanical load for any signs of binding, friction, or excessive resistance (e.g., worn bearings, pump cavitation).

3. 3

   3. Verify that the motor thermal overload parameters (e.g., P1-01 (Motor Rated Current), P1-03 (Motor Overload Class)) are correctly configured to match the motor and application.

4. 4

   4. Check the motor cooling fan for proper operation and ensure the motor's cooling fins are clear of dust and debris.

5. 5

   5. Monitor the motor surface temperature using an IR thermometer and compare to motor insulation class limits (e.g., Class F max 155°C).

6. 6

   6. If the motor is consistently operating above its FLA, consider reducing the load or upsizing the motor and/or soft starter.