Induction Motors: Main Types and Different Applications

An induction motor is a generally used AC electric motor. In an induction motor, the electric current in the rotor needed to produce torque is obtained via electromagnetic induction from the rotating magnetic field of the stator winding. The rotor of an induction motor can be a squirrel cage rotor or wound type rotor.

Used in different applications, induction motors are also called Asynchronous Motors. This is because an induction motor always runs at a slower speed than synchronous speed. The speed of the rotating magnetic field in the stator is called synchronous speed.

Induction machines are the most frequently-used type of motor used in residential, commercial, and industrial settings so far. The characteristic features of this three phase AC motors are:

• Simple and rough construction
• Affordable and low maintenance
• High reliability and highly proficient
• No requirement of additional starting motor and necessity not be synchronized

Two types of Induction Motors

Single phase induction motor

The single-phase induction motor does not self-start. The main winding carries a sporadic current when the motor is attached to a single-phase power supply. It is quite logical that the cheapest, most reduced upkeep sort engine ought to be used most regularly. Based on their way of starting, these machines are categorized differently. Those types are shaded pole, split phase, and capacitor motors. Also, capacitor motors are started with capacitor, run with capacitor and have permanent capacitor motors. 

In these single-phase types of motors the start winding can have a series capacitor and a centrifugal switch. When the supply voltage is applied, current in the main winding holdups the supply voltage because of the main winding impedance. And current in the start winding leads/lags, the supply voltage depending on the starting mechanism impedance. The angle between the two windings is sufficient phase difference to provide a rotating magnitude field to produce a starting torque. The point when the motor reaches 70% to 80% of synchronous speed, a centrifugal switch on the motor shaft opens and disconnects the starting winding.

Applications of Single-phase Induction Motors

The single-phase induction motors are used in low power applications. These motors are widely used in domestic and industrial applications. Some of the applications are mentioned below:

• Pumps
• Compressors
• Small fans
• Mixers
• Toys
• High speed vacuum cleaners
• Electric shavers
• Drilling machines

Three-Phase Induction Motor: 

Being self-starting, the three-phase induction motors use no start winding, centrifugal switch, capacitor, or other starting device. Three-phase AC induction motors have various uses in commercial and industrial applications. The two types of three-phase induction motors are- squirrel cage and slip ring motors. The features which make the squirrel cage motors widely applicable are mainly their simple design and rugged construction. With external resistors, the slip ring motors can have high starting torque.

Three-phase induction motors are used extensively in domestic and industrial appliances because these are rugged in construction requiring little to no maintenance, comparatively cheaper, and require supply only to the stator.

Applications of Three Phase Induction Motor

• Lifts
• Cranes
• Hoists
• Large capacity exhaust fans
• Driving lathe machines
• Crushers
• Oil extracting mills
• Textile and etc.

About the Author(s)

Princy A. J

Princy holds a bachelor’s degree in Civil Engineering from the prestigious Tamil Nadu Dr. M.G.R. University at Chennai, India. After a successful academic record, she pursued her passion for writing. A thorough professional and enthusiastic writer, she enjoys writing on various categories and advancements in the global industries. She plays an instrumental role in writing about current updates, news, blogs, and trends.