Question 216Electricity & Electronics - Assistant Engineer

The correct answer is D) an open run or start winding. A split-phase induction squirrel-cage motor requires both a run winding and a start winding to start and come up to speed. If either the run winding or the start winding is open, the motor will not be able to start, even with the rated voltage, frequency, and load applied. This is because the open winding prevents the necessary starting torque from being generated. The other options are incorrect because a shorted rotor bar, shorted centrifugal switch, or shorted thermal protector would not prevent the motor from starting and coming up to speed, as they are not directly related to the motor's windings.