A motor core, also referred to as the stator core or rotor core, is the central magnetic component of an electric motor. It is constructed from thin laminations of silicon steel (also known as electrical steel) stacked together to minimize energy loss due to eddy currents.
What Does a Motor Core Do?
The motor core creates the magnetic circuit through which the electromagnetic force is transferred. In AC induction motors, the stator core houses the copper windings that create a rotating magnetic field. The rotor core then responds to this rotating field, inducing current and producing torque.
Types of Motor Cores
**1. Stator Core** The stationary part of the motor that holds the stator windings. It is typically made from thin laminations of grain-oriented electrical steel (GOES) or non-grain-oriented electrical steel (NGOES).
**2. Rotor Core** The rotating part of the motor. It is assembled from stacked silicon steel laminations and houses either copper bars (squirrel cage motors) or permanent magnets (BLDC/IPM motors).
Key Material: Electrical Steel
Electrical steel (silicon steel) is the key material for motor cores. It comes in two varieties: - **CRNGO (Cold-Rolled Non-Grain-Oriented)**: Used in rotating machines where flux direction changes continuously - **CRGO (Cold-Rolled Grain-Oriented)**: Used in transformers where flux flows in one direction
Applications
Motor cores are used in virtually every industry: - Industrial AC motors (pumps, fans, compressors) - EV traction motors - Servo motors - Generators - Transformers