The theoretical speed of the rotating magnetic field created by the stator in an AC motor. It is determined strictly by the supply frequency and the number of magnetic poles in the motor design. An induction motor must run slightly below this speed to produce torque, while a synchronous motor locks into it exactly.
Heard on the job
We've a four-pole motor on a 60 hertz supply, so the synchronous speed is 1800 RPM.
Related terms
Slip
Shortfall between the speed of an induction motor's rotating field and the actual speed of its rotor.
Squirrel-cage motor
An AC induction motor featuring a rotor made of parallel conductive bars shorted by end rings.
Induction motor
An alternating current motor where the rotor current is induced by the magnetic field of the stator.