Specifications

FORM 160.80-NOM1

YORK INTERNATIONAL

LD00476

FIG. 31 – MOTOR STATOR TEMPERATURE AND INSULATION RESISTANCES

Minimum Insulation Resistance vs. Temperature (per IEEE Std 43)

YT CodePak Open Motors

1. Megohm readings should be taken after Megohm voltage has been applied one minute.

2. If insulation resistance lies to the right of the applicable curve, the motor is acceptable for use.

3. If insulation resistance lies to the left of the applicable curve, the motor should not be run. The motor

should be heated to 250ºF in an effort to remove moisture and obtain an acceptable reading at

room ambient. This can be done either by baking in a forced hot air oven or, if proper voltage is

available, apply 5 - 10% of rated voltage to motor windings.

4. Any gradual or abrupt decrease in Megohm readings over an extended period of time is an

indication of deterioration of insulation and/or moisture absorption or oil/dirt contamination.

5. Megohm readings of individual phase coils of 200 - 600V motors should be made with coils not

under test being grounded.