What is the special feature of single phase induction motor?

The special feature of a single-phase induction motor is that it does not inherently have the ability to start rotating from a standstill position by itself. This is because a single-phase induction motor, when powered by a single-phase AC supply, produces a magnetic field in its stator winding that pulsates rather than rotates. To overcome this limitation and enable the motor to start, additional mechanisms are used, such as:

1. Capacitor Start Mechanism: A capacitor is connected in series with a starting or auxiliary winding, which shifts the phase of the current in the auxiliary winding relative to the current in the main winding. This phase shift creates a rotating magnetic field, which allows the motor to start. Once the motor has reached a certain speed, a centrifugal switch disconnects the starting winding.

2. Split Phase Mechanism: In split-phase motors, there are two windings: a starting winding and a running winding. The starting winding has a higher resistance and lower inductance compared to the running winding, creating a phase difference between the currents in the two windings. This phase difference produces a rotating magnetic field needed to start the motor. Similar to the capacitor start mechanism, a centrifugal switch opens to disconnect the starting winding once the motor reaches a specific speed.

3. Permanent Split Capacitor (PSC) Mechanism: This is used in motors that require smooth running without the need for high starting torque. A capacitor is permanently connected in series with the starting winding,