Megging the motor - mechanical starter
While the main disconnect switch and compressor motor starter are open, meg the motor as
follows:
1. Using a megohm meter (megger), meg between phases and each phase to ground. See
Figure 16. Interpret these readings using the graph shown in Figure 18.
2. If readings fall below the shaded area, remove the external leads from the motor and repeat
the test.
Note:
Meg the motor with the starter at ambient temperature after 24 hours of idle
standby.
Figure 16: Megging the motor windings - mechanical starter
Megging the motor - VFD powered or solid state soft starter
1. Disconnect power leads from VFD or solid state starter to the motor. This is required so that
only the motor is subjected to the applied voltage from the megger tester.
2. Using a megohm meter (megger), meg between phases and each phase to ground. See
Figure 17. Interpret these readings using the graph in Figure 18.
Figure 17: Megging the motor - VFD or solid state soft started motors
Model YK Style G R-134a or R-513A
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