Asynchronous Clutch

an electromagnetic slip clutch for the smooth regulation of the speed of rotation of a driven mechanism, with a practically constant rate of rotation of the electric motor. An asynchronous clutch consists of a driven part—the rotor of an asynchronous electrical machine (most often with a short-circuited winding)—and a driving outer part having salient poles that are excited by direct current from an external source. During rotation the driven part lags behind the driving part. As a result of electromagnetic induction a torque is developed which pulls the driven part in the same manner as the rotating magnetic field of an asynchronous electric motor pulls the rotor after itself. By varying the excitation current it is possible to adjust the speed of rotation of the driven part of the clutch over a wide range. Asynchronous clutches are utilized in the electric drives for ships’ propellers, in wind tunnels, and so on.