The hidden pole rotor winding does not need to be subjected to AC withstand voltage test, and the insulation resistance can be measured with a 2500V ohmmeter instead of AC withstand voltage.
The cryopole rostator windings can be used without AC pressure testing and can be replaced by AC pressure resistance with a 2500V eurometer measurement of insulation resistance.
AC withstand voltage test is not required for hidden pole rotor winding, and 2500V ohmmeter can be used to measure insulation resistance instead of AC withstand voltage.<br>