Which of the following is NOT a characteristic of shaded pole single phase motors?

Option 4 : High overload capacity

• The shaded pole motor is simply a self-starting single-phase induction motor whose one of the pole is shaded by the copper ring.
• The copper ring is also called the shaded ring. This copper ring acts as a secondary winding for the motor.
• The shaded pole motor rotates only in one particular direction, and the reverse rotation of the motor is not possible.
• The stator of the shaded pole single phase induction motor has salient or projected poles.
• These poles are shaded by copper band or ring which is inductive in nature.
• The poles are divided into two unequal halves. The smaller portion carries the copper band and is called a shaded portion of the pole.

Advantages:

• Very economical and reliable.
• Construction is simple and robust because there is no centrifugal switch.

Disadvantages:

• Low power factor.
• The starting torque is very poor.
• The efficiency is very low as the copper losses are high due to presence of copper band.
• The speed reversal is also difficult and expensive as it requires another set of copper rings.
• Low overload capacity

Applications:

• They are suitable for small devices like relays and fans because of their low cost and easy starting.
• Used in exhaust fans, hairdryers and also in table fans.
• Used in air conditioning and refrigeration equipment and cooling fans.
• Used in record players, tape recorders, projectors, photocopying machines.
• Used for starting electronic clocks and single-phase synchronous timing motors.