E.THT

Inverter Overload shut-off (electronic overcurrent protection)

Mitsubishi Electric · A500 Inverter

What does E.THT mean?

This protective function activates to prevent damage to the inverter's output transistors. It triggers when a current exceeding 150% of the inverter's rated output current flows for an extended duration, typically if immediate overcurrent protection (for currents >200%) does not activate. The protection utilizes inverse-time characteristics, with an overload immunity of 150% for 60 seconds, leading to an inverter output stop.

Repair Steps

  1. 1

    Measure the output current from the inverter (terminals U, V, W) to the motor and compare it against the inverter's rated output current.

  2. 2

    Evaluate the mechanical load on the motor for any conditions that might cause excessive current draw on the inverter, and reduce the load if necessary.

  3. 3

    Inspect the driven equipment for any signs of mechanical binding, excessive friction, or misalignment that could increase the power demand.

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Verified technical data. Last updated: March 2026
Source: Mitsubishi Electric A500 Inverter