Low-Speed Overload Protection

What does E38 mean?

This fault indicates an overload condition detected when the motor is operating at very low speeds. The inverter's protection mechanism trips to prevent motor damage that can occur when operating heavy loads at low frequencies, where cooling efficiency might be reduced and current demand is high.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Check motor cooling and ensure proper ventilation, as fan effectiveness can decrease significantly at low operating speeds.

2. 4

   Consider using a motor with a higher service factor or forced cooling if continuous low-speed, high-torque operation is required.

3. 5

   Increase the minimum frequency setting (H121) if the application allows, to avoid prolonged very low-speed operation under heavy load.