HV is a test we use in engine and generator windings.

The output voltage of the tester can be adjusted and it can supply maximum 25 kV AC voltage.

Winding V = (2 * U + 1000) AC Voltage is applied within 1 minute

This test is applied after the coils are connected each time the stator is turned on.
Thus, during the winding can occur in the bob or may occur in manufacturing
Errors have occurred and the coils are resistant to the network conditions after winding
It does not seem to be.