4. AC motor protection

4.1 High-power asynchronous motors

The high-power induction motors considered in this article are motors with a power rating of more than a few hundred kilowatts. This threshold, which defines the choice of a protection system, is not absolute. It depends on the importance attached to the motor-driven auxiliary equipment in the industrial process.

It is common for such motors to be supplied with high-voltage HTA from 3 to 6.6 kV, or even higher. The associated disconnecting device may be a fuse, combined with a three-pole contactor, or a circuit-breaker ...