Absence of motion detector for e.g. crane motor - uses optical, mechanical, or proximity detection and controller which removes electric supply if mechanism fails to move within set time

摘要

The controller is partic. applicable to travelling cranes and incorporates stop/go control buttons in a controller which detects absence of motion and automatically cuts off the electric supply should a failure occur. The controller has a relay which may be actuated by any of several detectors which are electrically isolated one from the other. An electronic timer circuit commences timing when the command is given to the crane, and if no motion is detected within a set time interval the control relay RA is released, removing the electric supply from the crane motors. The motion detector may be a photodetector, a mechanical switch, or a capacitive or inductive proximity transducer.