Use of machine hipot testing in electric utilities

Abstract

EPRI recently sponsored a survey of motor and generator users and manufacturers about their use of DC and AC overvoltage testing. Such testing is intended to assure machine owners that the stator and rotor winding insulation is fit for use. Questions focused on both commissioning tests and maintenance tests. The survey explored the circumstances under which hipot testing is done, the preferences of AC vs. DC testing, the specific test methods used, as well as the test voltages. This paper presents the results of the survey.