External thermal relay operation

What does E.OHT mean?

This fault signifies that an external thermal relay (for motor overheat protection) or an internal motor temperature relay has tripped, causing its contacts to open. The inverter has stopped its output to protect the motor from overheating. This function is active only when the 'OH' signal (value 7) is set in any of Pr. 178 to Pr. 182 (input terminal function selection). Prolonged motor overheating can lead to winding insulation breakdown and motor failure.

Complete Troubleshooting Guide

1. 1

   Check the motor and its operating environment for signs of overheating; ensure proper ventilation and cooling.

2. 2

   Reduce the mechanical load on the motor or decrease the operating frequency/speed if possible.

3. 3

   Verify that the 'OH' signal (value 7) is correctly assigned to one of the input terminals (Pr. 178 to Pr. 182).

4. 4

   Reset the inverter after the motor has cooled down and the thermal relay has automatically or manually reset.