Rotational speed or direction detector especially of induction motor

摘要

The device is installed in a motor having a fan (1) fitted to the rotor shaft under a cover (2). A pulse source (13) on the outside of the cover co-operates with vanes (9) co-rotating on the inside within the fan space (14). The pulses are produced by an inductive proximity sensor influenced by the passage of vanes of electrically conductive material (e.g. steel or Al) uniformly distributed around a disc (6) attached to the fan on the side facing the motor.