Introduction to AC induction motors

Induction motors are very popular in industries and commercial application nowadays. Induction motors are commonly working using alternating current supply. In industries and commercial application almost  85% population of equipments using induction motors for their operation.

AC induction motors are mainly classified into two types.

1. Squirrel cage induction motor
2. Slip ring induction motor

Induction Motors are popular because of thee listed advantages over a DC motor

Advantages of induction motor

1. Rigid in construction.
2. Smaller, compact size comparing with DC motor.
3. Low maintenance cost, because it does not have any commutator and brush assembly for injecting current to rotor
4. They can be operated in chemical plants as no sparking possibilities
5. Induction motors almost constant speed motors. Because its torque speed characteristics in almost same as DC shunt motor
6. High starting torque is possible using slip ring induction motor
7. Speed control is possible using VFD (variable frequency drives).
8. Initial and operation cost are less compared with DC motor
9. Easy Maintenance

Even an induction motor having enormous advantages , it also having few advantages too,

1. It has less starting torque compared with DC motors
2. As motors are inductive loads , it operates in lagging power factor
3. Speed control method is very complicated.
4. Linear speed control is not possible , other than variable voltage frequency method controlling
5. Frequent reversal of motor affect stress on motor

Area of application of induction motors

1. In chemical plant run process equipments
2. In production industries operating of production equipments,
3. In conveyor belt operation
4. In food and paper industries run its process plants
5. In textile industries operation of textile machines
6. Operation of pumps, fans, compressors