Types of AC Induction Motors

As mentioned before, squirrel-cage induction motors are very prevalent in industry, in sizes from fractional horse powers up to tens of megawatts. They are simple, rugged, and self-starting, and maintain a reasonably constant speed from light load to full load, set by the frequency of the power supply and the number of poles of the stator winding. This simplifies application and replacement of these motors. They are also called induction motors or asynchronous motors. These motors are used widely in different industries as they are feasible with low maintenance needs, efficient, and generally inexpensive.

There are two main types of AC induction motors: single phase and three phase motors. Single phase motors are not self-starter while three phase motors are. Here is why:

Single phase induction motors

This kind of motors just have one phase to rotate the rotor. AC power supply is a sinus wave which generates a pulsed magnetic field in the stator. Pulsed magnetic field is visualized as two contrasting magnetic fields, no initiating torque is generated to make the rotor to rotate. Thus, an initial inertia is needed to start the motor.

Single phase motors are divided into split phase, capacitor start, capacitor start and capacitor run and shaded pole.

Three phase induction motors

In three phase AC motors, three phases with 120 degrees phase difference generates a rotating magnetic field in stator and this rotation makes the rotor to rotate.

The main two types of three phase motors are squirrel cage and slip ring motors.

Advantages of Induction motors

• Low price
• Low maintenance costs
• Ease of operation
• Constant speed
• High start torque
• High durability

Because of these advantages, these motors have many applications in different industries, home appliances, pumps and farms. Please call us for your electric motor enquiries.