Which of the following methods should be used to test for an 'open' stator winding coil in a wye-connected AC squirrel cage induction motor?

Correct Answer: Option C — Test with an ohmmeter with the test leads across each pair disconnected motor lead leads in succession and compare resistances.

To detect an open stator coil in a wye-connected motor, an ohmmeter is measured across each pair of disconnected motor leads. IEEE 45 troubleshooting standards dictate that compared phase-to-phase resistance values quickly reveal infinite resistance or imbalance indicative of an open winding.