An AC motor consists of two main parts a rotor, a component that rotates, and a stator, which is stationary. Most common AC motors use the squirrel cage rotor, which is found almost in all domestic and light industrial AC motors.
There are two types of DC motors currently in use; the Brushed DC electric motor and Brushless DC electric motor. In brushed motors, brushes are used to maintain electrical connectivity with the rotor winding, and internal commutation changes the polarities of the electromagnet to keep the rotational motion sustained. Generally DC motors deliver less torque power than the AC motors. In small DC motors, the number of windings is low, and two permanent magnets are used as the stator. Power mains can supply very large currents required for the operation of the heavy duty motors.
AC vs. DC Motors
The two major differences between AC and DC motors is the starting mechanism and the type of electricity they can run on. An AC motor requires a starter mechanism, but the DC motors do not need a starter mechanism. AC motor works on AC electricity while DC motor works on DC electricity. DC motors are single phase motors whereas AC motors are both 1 and 3 phases.
3 Phase Induction Motors
Three phase induction motors are a popular choice for many industrial applications for a number of reasons:
- Non-complex construction – They don’t require permanent magnets, brushes or windings on the rotor.
- Direct Hookup – These motors can run directly off of the electric distribution grid.
- Low Cost
- Rugged Construction – Durable and suitable for hazardous environments.
- Minimal Maintenance – Due to not having brushes, they are long lasting.
Synchronous Electric Motors
A synchronous motor has a special rotor construction that lets it rotate at the same speed — that is, in synchronization — with the stator field. One example of a synchronous motor is the stepping motor, widely used in applications that involve position control.