What happens to the rotor current in an induction motor?

In an induction motor, the rotor current plays a critical role in the operation of the motor. When the stator windings are energized, they create a rotating magnetic field. This magnetic field induces a current in the rotor due to electromagnetic induction, which occurs when the rotor is exposed to the changing magnetic field.

The current in the rotor generates its own magnetic field. According to Lenz's Law, this induced field interacts with the rotating magnetic field produced by the stator. Specifically, the induced rotor magnetic field opposes the stator's rotating magnetic field. This interaction creates torque, which is necessary for the rotor to begin turning. If the rotor were to catch up with the rotating magnetic field, the relative motion between them would cease, and thus, no current would be induced in the rotor, leading to the motor stopping.

Understanding this relationship is fundamental for grasping how induction motors work, especially the dynamic nature of the rotor currents in response to the stator field and the creation of torque.