Using the temperature correction factor for the winding insulation temperature graph shown in the illustration, what would be the correction factor and the corrected temperature to 40 degrees C for a motor with a insulation resistance of 4 megohms measured at 50 degrees C? EL-0046

Correct Answer: Option A — The temperature correction factor is 2 and the corrected resistance is 8 megohms at 40 degrees C.

Insulation resistance halves for approximately every 10°C rise in temperature. Measuring 4 megohms at 50°C requires a temperature correction factor of 2 when normalizing to the standard 40°C reference baseline, yielding a corrected insulation resistance value of 8 megohms per IEEE 45 testing protocols.