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Can reactors be considered “IGBT-protected” by passing a 4000V hipot test?

“IGBT protected” is a fabrication. A reactor applied at the output terminals of an IGBT based drive will see a maximum of 680V for a 480V system. A hipot test is a method of testing insulation integrity, and is a destructive test. In the real world, the only time that a reactor might see excessive voltages is when it is applied at the end of a long set of motor leads, which is an ill-advised and improper installation. This technique is used as a last ditch effort, in an attempt to batter the reactor with high overshoot voltages, instead of the motor. It will eventually lead to insulation destruction in the reactor, regardless of the reactor’s ability to pass a one or two-time 4000V hipot test back at the factory. In addition, this sacrificial lamb technique does nothing to protect the insulation of the motor lead wires, another susceptible system component. The appropriate solution to dv/dt longlead motor failures is the V1k output filter.