Zero Overload Fault

What does 49 mean?

This fault occurs when the motor requires an excessively high current while operating at zero hertz (stopped), or if the P38 – [Boost Volts] parameter is set too high. This condition can lead to motor and controller overheating even before motion begins.

• Mechanical binding or excessive static friction in the load, preventing the motor from rotating freely at zero hertz.
• Motor brake (if equipped) not fully disengaging, causing the motor to try and overcome a locked rotor condition.
• P38 (Boost Volts) parameter set too high, causing excessive voltage to be applied at zero speed, leading to motor saturation and high current.
• Motor winding insulation breakdown (e.g., turn-to-turn short) leading to excessive current draw even at standstill.
• Incorrect motor nameplate data (e.g., P5-01 (Motor Rated Current), P5-02 (Motor Rated Voltage)) entered into the drive, leading to an inaccurate motor model.

Click steps to track your progress.

1. 1

   1. Power off the drive and disconnect the motor. Attempt to manually rotate the motor shaft to confirm free movement and verify the brake (if present) releases correctly.

2. 2

   2. Measure motor winding resistance (U-V, V-W, W-U) and insulation resistance (each phase to ground) using a multimeter and a megohmmeter (at 500VDC or 1000VDC).

3. 3

   3. Verify and adjust the P38 (Boost Volts) parameter. Reduce it incrementally (e.g., from 5% to 2%) until the fault clears, ensuring proper starting torque.

4. 4

   4. Re-enter the precise motor nameplate data into the drive parameters (P5-01 to P5-05) and perform a motor auto-tuning procedure.

5. 5

   5. Monitor the motor output current (e.g., M0-01) and output voltage (e.g., M0-02) at zero speed while observing the motor for any signs of vibration or overheating.