The most common type of AC motor being used throughout the work today is the “Induction Motor”. Applications of three-phase induction motors of sizes varying from half a kilowatt to thousands of kilowatts are numerous. They are found everywhere from small workshops to large manufacturing industries.
Advantages of three-phase AC induction motor
- Simple design
- Rugged construction
- Reliable operation
- Low initial cost
- Easy operation and simple maintenance
- Simple control gear for starting and speed control
- High efficiency.
The induction motor originated in the year 1891 with crude construction (the machine principle was invented by NIKOLA TESLA in 1888.). Then an improved construction with distributed stator windings and a cage rotor was built. The slip ring rotor was developed after a decade or so. Since then a lot of improvement has taken place in the design of these two types of induction motors. A lot of research work has been carried out to improve its power factor and to achieve suitable methods of speed control
Three-phase induction motors are constructed into two major types:
- Squirrel cage Induction Motors
- Slip ring Induction Motors