Difference between the Rotor and the Stator


The stator and rotor both are the parts of the electrical motor. The significant difference between the rotor and the stator is that the rotor is the rotating part of the motor whereas the stator is the stationary part of the motor.


The stationary electrical part of the motor. It contains a number of windings whose polarity is changed all the time when an alternating current (AC) is applied. This makes the combined magnetic field of the stator rotate. All stators are mounted in a frame or housing. The stator housing of motors is mainly made from aluminium for motors up to 22 kW, while motors with higher outputs have cast-iron stator housings. The stator itself is mounted inside the stator housing. It consists of thin, stacked laminations that are wound with insulated wire. The core contains hundreds of these laminations. When power is applied, an alternating current flows through the windings, creating an electromagnetic field across the rotor bars. The alternating current (AC) makes the magnetic field rotate.

The stator insulation design is classified. This classification is defined in IEC 62114, which have different insulation classes (temperature classes) and temperature rises (∆T).Stators with two, four and six poles are the most commonly used in connection with pumps, because the speed determines the pressure and the flow. The stator can be designed to handle various voltages, frequencies and outputs and a varying number of poles.

Difference between the Rotor and the Stator


The rotating part of the motor is known as the rotor. The rotor core and the rotor winding are the rotor part. The rotor winding is excited by the DC supply. The squirrel cage and the phase wound are the rotor types.

When the stator’s moving magnetic field cuts across the rotor conductor bars, a current is produced. This current circulates through the bars and creates magnetic fields around each rotor bar. As the magnetic field in the stator keeps changing, so does the field in the rotor. This interaction is what causes the rotor to move.

Like the stator, the rotor is made of a lamination stack. Contrary to the stator, which is filled with copper wire, the rotor is filled with cast aluminium or silumin bars, that acts as conductors.

Difference between the Rotor and the Stator

Difference between the Rotor and the Stator

Difference between the Rotor and the Stator

Also read

Basics of Motor Control

Introduction to Induction Motor

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