Which of the following single-phase motors has relatively poor starting torque ?

Universal motor
Repulsion motor
Capacitor motor
All single phase motors have zero starting torque

The correct answer is: B. Repulsion motor

A repulsion motor is a type of single-phase motor that has relatively poor starting torque. This is because the stator windings and rotor windings are not directly connected, which means that there is no initial magnetic field to start the motor. The motor must rely on the induction of a magnetic field from the stator windings to start the rotor spinning. This can be a slow process, and the motor may not be able to start at all if the load is too heavy.

A universal motor is a type of single-phase motor that can be used on both AC and DC power. It has good starting torque and can be used in a variety of applications, such as vacuum cleaners, power tools, and hair dryers.

A capacitor motor is a type of single-phase motor that uses a capacitor to improve the starting torque. The capacitor creates a phase shift between the stator and rotor windings, which results in a stronger magnetic field. This makes it easier for the motor to start, even when the load is heavy.

All single-phase motors do not have zero starting torque. Some single-phase motors, such as universal motors and capacitor motors, have good starting torque. However, repulsion motors have relatively poor starting torque.