HIPOT TEST VOLTAGES
DC Hipot test technology was developed after AC Hipot tests were in use. Thus, a DC Hipot test voltage is often derived from a typical AC Hipot test voltage that has been proven to work well over many decades.
For proof tests of new unused machines, the test voltages are as follows per IEEE 95, IEC and ANSI/EASA AR100:
Tests of Used Equipment:
The standards say that an AC voltage Hipot test ranging from 125% to 150% of the rated RMS line to line voltage, equivalent to about 65% to 75% of 2E+1000 V, has proven to be adequate. Therefore, the formula in the standards for DC Hipot test voltage with used machines is as seen below. In the motor repair industry, the test voltage commonly used is 2E+1000V. This formula calculates a test voltage 10% lower than the formula used in the standards. For a 460V motor this difference is about 200V, for a 4000V motor 945V and for a 13.8kV motor about 3000V less.
For most applications, either formula will work fine. The formula used by the standards provide a little more information since the test voltage is a little higher.
The iTIG II motor analyzer can set either formula as the default formula for automatic calculation of the Hipot test voltage.