As mentioned above, the suggested test voltage for the Megohm test is 1.7 times the
applied/operating line voltage for the motor. For example a 480 volt motor would be
tested at 480V*1.7=816VDC. Recommended test voltages can also be found in IEEE 95,
ANSI C50.10-1977, IEC 34.1, NEMA MG-1 and EASA technical manuals (see chapter
2).