Types of 3 Phase Induction Motor

Three phase induction motor definition

A three-phase induction motor is an asynchronous motor that operates at a different speed than a synchronous one and uses a three-phase power supply.

Stator

The stator is the stationary part of the motor that receives a three-phase power supply to generate a rotating magnetic field.

Major component composition

Stator frame

The stator frame is the exterior of the three-phase induction motor. It supports the stator core and the field windings, providing protection and mechanical strength for the internal parts. The frame is made of die cast or prefabricated steel and must be strong and rigid to maintain a small gap between the rotor and the stator and prevent unbalanced magnetic pulling.

Stator core

The main function of the stator core is to carry AC magnetic flux. It is laminated to reduce eddy current losses, with a thickness of 0.4 to 0.5 mm per lamination. These sheets are stamped together to form the stator core, which is housed in the stator frame. The lamination is made of silicon steel to help reduce lag losses.

Stator winding or field winding

The slot outside the stator core of the three-phase induction motor bears the three-phase winding. The three-phase winding is supplied by a three-phase AC power supply. The three phases of the winding are connected in a star or triangle shape, depending on the type of starting method used.

The squirrel cage motor is mostly started by the star triangle stator, so the stator of the squirrel cage motor is connected by a triangle. The slip ring three-phase induction motor is started by inserting a resistor, so the stator windings can be connected in a star or triangle shape. The winding winding on the stator of the three-phase induction motor is also called the field winding, when the winding is excited by the three-phase AC power supply, it will produce a rotating magnetic field.

Rotor

The rotor is attached to a mechanical load and rotates within the stator's magnetic field.

Type of rotor

• Squirrel cage rotor

• Slip ring rotor