A motor with only damper windings is called an induction motor. From the construction point of view, An induction motor is the most modest electrical machine. The working principle of the induction motor is that the ac in the rotor of the motor is required to generate torque that is gained through electromagnetic induction which results from the stator winding’s rotary magnetic field. There are two types of Induction motors, single-phase induction motor and three-phase induction motor. Single-phase is classified into four types whereas 3-phase is classified into two types.
Single-phase induction motor
The single-phase induction motor is not self-starting. The main winding carries an alternating current when the motor is connected to a single-phase power supply. they are the least expensive, their maintenance cost is low, and can be utilized most regularly. These are of different types based on their way of starting since these are not the self-starting motor.
Types of Single-Phase Induction Motor
Split Phase Induction Motor
The split-phase induction motor is also known as a Resistance Start Motor. This motor consist of a stator and a single cage rotor. The stator includes two windings called starting winding and main winding. These two windings are moved 90 degrees. The main winding includes very little resistance and a high inductive reactance and the starting winding includes less inductive reactance and very high resistance. Due to the less starting torque, this motor is not applicable for drives that need above 1 KW. In a washing machine, floor polishers, AC fans, mixer grinder, blowers, centrifugal pumps, drilling & lathe machine split-phase induction motor is used.
Capacitor Start Induction Motor
A capacitor start induction motor is a 1-phase motor that consists of a stator and a rotor with a single cage. The stator of this motor has two windings namely main winding and an auxiliary winding. The arrangement of these two windings is like they are placed 90 degrees separately in space. where frequent starts are needed Capacitor start induction motor is used. It is used in AC compressors & the refrigerators, pumps, machine tools, and conveyors.
Capacitor Start & Capacitor Run Induction Motor
The capacitor run induction motor working principle is the same as capacitor start induction motor. We know that a 1-phase induction motor is not self-starting as the magnetic field generated is not a rotary type. So for generating . In a split-phase induction motor, the resistance must be there to create phase difference for a rotary magnetic field, induction motors require phase difference however in Capacitor Start & Capacitor Run Induction motors; the capacitor will make a phase difference. The voltage is guided by the current flowing throughout the capacitor. They are mainly used within grinders, conveyors, compressors, air conditioners, etc because of their high starting torque.
Shaded Pole Induction Motor
A shaded pole induction motor is a self-starting 1-phase induction motor. In this motor one of the poles is shaded through the copper ring which is called the shaded ring. This ring’s main function is to act as a secondary winding in the motor. the power losses are extremely high, the power factor is less & induced starting torque can also be extremely low in the shaded pole. They are mostly used in small devices such as fans, relays because of their easy starting & low cost. they are also used in hairdryers, exhaust fans, table fans, air conditioning, cooling fans, refrigeration device, record players, projectors, tape recorders, machines for photocopying.