In the split-phase induction motor, both main winding and starting winding are displaced _________ in space.

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SSC JE Electrical 9 Oct 2023 Shift 3 Official Paper-I

Answer 1

The correct answer is option 4.

Split-phase induction motor

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It is a type of 1ϕ induction motor whose starting frequency is limited and is NOT used for drives that require more than 1 kW.
It has a single cage rotor, and its stator has two windings known as main winding and starting winding. Both the windings are displaced 90° in space.
The main winding has very low resistance and a high inductive reactance whereas the starting winding has high resistance and low inductive reactance.
A resistor is connected in series with the auxiliary winding. The current in the two windings is not equal as a result, the rotating field is not uniform. Hence, the starting torque is small, of the order of 1.5 to 2 times the stated running torque. At the start of the motor both the windings are connected in parallel.
As soon as the motor reaches the speed of about 70 to 80 % of the synchronous speed the starting winding is disconnected automatically from the supply mains.