HOW SINGLE PHASE INDUCTION MOTORS WORK?

Sustainable development through Energy Saving forms the crux of the society today. In the field of Industrial Electrical and Power Transmission, energy consumed by various machines represents the largest part of electricity consumption. Higher efficiency will not only reduce extensive costing but will proportionally decrease the fossil fuel burden.

Talk about multi-functional, economical or wide range of applications – Single phase power systems are all in one. Not only do they have their prominence established in domestic and commercial arenas, they mildly do cover the certain industrial applications as well.

Single Phase Induction Motor systems guarantee comfortable pockets when compared to three-phase systems. All the check points for power requisite are met when it comes to residence, mid-sized corporate offices, commercial shops, stores etc.

The single phase induction motors are simple in make, reliable and robust, easy to repair and maintain as well as exhibit excellent durability.

Before getting into the working of these exemplary motors, it is imperative that their classification is thoroughly understood.

The SPAC motors can be bifurcated into:

  1. Single Phase Induction Motors
  2. Commutator motors

Single Phase Induction Motors

Sub types:

  • Split Phase Induction motor
    • Used for starting loads such as fans, blower-fans, mixer-grinders, and washing machines.
  • Capacitor Start Induction motor
    • Used in air conditioners, compressors of Refrigerators, conveyor belts, and other machine applications.
  • Capacitor Start capacitor-run Induction motor
    • Used in air conditioners, refrigerators, and pumps.
  • Permanent Capacitor
    • Used in fans, blowers, air conditioners, and compressors in refrigerators.
  • Shaded Pole type
    • Used for low starting applications such as in cooling fans, exhaust fans, blowers, fans of different types, relays, and in table fans.

Working of Single phase Induction motor

Here, we are typically going to focus on how single phase induction motors work?

To begin with, any electric motor whether classified as AC or DC motor requires two fluxes which on interaction produce the necessary torque.

Single phase AC supply applied to the stator winding of single phase induction motor -> AC current flows through the main winding -> This AC produces alternating flux (main flux) ->main flux links with the rotor conductors and hence cut the rotor conductors->emf gets induced in the rotor ->rotor current is produced->rotor current in turn produces rotor flux-> main flux along with rotor flux produce the required torque which is used by the motor to rotate.

Since this flux is produced due to the induction principle so, the motor working on this principle got its name as an induction motor.

Single phase induction motorThree phase induction motor
Simple, reliable and cost friendlyComplex, costly and not meant for small power requirements
Low electrical power factorHigh electrical power factor
Starting torque lowStarting torque high

Single phase induction motors are simple, robust, reliable and cheaper for small ratings. They are available up to 1 KW rating.

Top 3 benefits of a single phase induction motor

  1. Can be operated in hazardous conditions, since sparking is nil due to absence of brushes.
  2. It has full load efficiency ranging from 85% right upto 97%
  3. Durable and mechanically strong, hence independent of environmental conditions.

Thank You For Reading.

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