In AC motors, what does the term 'slip' refer to?

In the context of AC motors, 'slip' specifically denotes the difference between the synchronous speed of the magnetic field generated by the stator and the actual speed at which the rotor turns. Synchronous speed is the speed at which the magnetic field rotates, which is determined by the frequency of the AC supply and the number of poles in the motor.

In practical operation, the rotor cannot reach this synchronous speed due to factors such as load and resistance within the motor. As a result, slip is expressed as a percentage of the synchronous speed and indicates how much slower the rotor spins compared to the rotating magnetic field. This phenomenon is vital for the operation of induction motors, as it creates the necessary relative motion between the stator's magnetic field and the rotor, allowing for torque production.

Understanding slip is crucial since it impacts the performance and efficiency of AC motors, affecting load handling and energy consumption. The other options do not accurately define slip; they pertain to different principles related to electrical systems and motor performance.