Below is a list of Synchronous Motor manufacturers from St. Charles, Illinois. Synchronous motors are a type of alternating current (AC) electric motor that run at synchronous speed, which refers to the speed of the rotating magnetic field within the motor. Also, synchronous motors are characterized by having zero slip, meaning that they do not have a difference in speed between the two rotating members within the motor. This is one of the key differences between synchronous motors and induction motors because induction motors require slip to properly function.