SOLUTION

• In order to self-start a single-phase induction motor one must create a rotating magnetic field on the stator. Therefore split phase motor has two winding one is starting winding and the other is main winding or running winding.
• The starting winding has fewer turns and a small diameter, therefore, it has high resistance and low inductance.
• The running winding has a heavier wire of more turns, therefore, it has low resistance and high inductance.
• As we know that for high inductance current lags behind voltage by a large angle and for high resistance, the current is almost in phase with the voltage.
• Hence, an induction motor has a lagging power factor since it withdraws reactive power from the Source to meet its magnetizing requirements. For the loading conditions, the power factor is 0.6 – 0.8 lagging. For the unloading condition, the power factor is 0.2-0.3 lagging.
• Single-phase motors hardly work with an efficiency of 55 to 60 %.