1. These motors are also called fractional horse-power or fractional kilowatt motors
  2. Single phase induction motors are used in homes, offices, factories etc.

Types of Single Phase induction Motors

Split phase induction motor

  1. Two windings auxiliary winding and main winding are used in this motors.
  2. The main winding is highly inductive and auxiliary winding has a greater resistance.
  3. Power factor is about 0.6 and efficiency is also about 60%.
  4. It is used for smaller sizes about 0.25hp.
  5. It is used in washings machines, fans, blowers, wood working tools, grinders and various other low starting torque applications.
  6. The direction can be reversed by reversing the connections of either starting (auxiliary) winding or running (main) winding.

Capacitor start motors

  1. Capacitor is of large value such that the motor will give high starting torque.
  2. Capacitor is electrolytic type.
  3. Capacitor employed is of short time duty rating.
  4. Centrifugal switch is used.
  5. Speed is almost constant within 5% slip.
  6. The direction of rotation can be changed by interchanging the connection of either starting or running winding.

Capacitor run motors

  1. This is also called fan motors.
  2. A paper capacitor is permanently connected in the starting winding.
  3. In these motors, electrolytic capacitor cannot be used since this type capacitor is designed only for short time rating and hence cannot be permanently.
  4. Efficiency is about 75%.
  5. It is usually used in fans, room coolers, portable tools, and other domestic and commercial electrical appliances.
  6. The direction of rotation can be changed by interchanging the connection of either starting or running winding.

Capacitor start capacitor run motors

  1. Capacitor used for starting winding is electrolytic type and for running winding is paper capacitor.
  2. Starting torque is high
  3. Higher power factor.
  4. Starting current is low.
  5. The only disadvantage is high cost.

Shaded pole motor

  1. Shaded pole motor is constructed with salient poles in stator.
  2. A 1/3rd portion of each core is surrounded by a copper strip forming a closed loop is called the shading band.
  3. Rotor is usually squirrel cage type.
  4. Direction of rotation cannot be reversed.
  5. These motors are used for small fans, electric clock, gramophones etc.
  6. Starting torque is very small.

Reluctance start motor

  1. The stator of a reluctance start motor is constructed with salient poles.
  2. The starting torque is achieved by creating non-uniform air-gap of the salient poles.
  3. Direction of rotation cannot be reversed.
  4. Very small starting torque.
  5. Their applications are limited.

Hysteresis Motors

  1. The rotor of hysteresis motor is made of hardened high-retentivity steel.
  2. These motors are used in driving high quality cassette players, compact disc players, record players, clocks etc.

Universal Motor

  1. Can be operated on ac as well as on dc supply at the rated voltage.
  2. Used in vacuum cleaners, sewing machines, electric hand drills, mixers, can openers, blenders, electric shavers, hair dryers etc.