What is the sliding?
The above mentioned velocity in an AC motor is theoretical because the real speed is lower for slip that is the difference between the speed of the rotating magnetic field (which is always synchronous) and the rotor in a non- synchronous induction motor. It is expressed as a percentage of synchronous speed. Slip generally increases with an increasing torque. The full load speed of a motor is lower of 2÷7% (slip of 2÷7%) than no load speed.