GB643211A - Improvements in electric control apparatus, particularly for effecting a given operation of an electromagnetic device upon a movable element reaching a given position - Google Patents

Abstract

643,211. Operating clutches. IGRANIC ELECTRIC CO., Ltd. Aug. 30, 1946, No. 26138. Convention date, Aug. 31, 1945. [Class 80(ii)] [Also in Groups XXII, XXX, XXXV, XXXVII and XL(c)] An electromagnetically operated clutch controlled by a valve 17 may be used to control the stopping of a conveyer 10. The voltage normally induced in winding 20d is equal to and of opposite polarity to that induced in winding 19b so that no voltage is impressed upon a condenser 18, the valve 17 thus being conductive to operate a relay 25 to close contacts 25b. Operation of a push button 28 then operates relay 27 through contacts 25b to operate an electromagnetic clutch to clutch the conveyer to a continuously rotating driving motor (instead of the relay 27 closing a circuit for a motor 13 as shown). When a core 20e moves into the air gap of the transformer 20 the voltage-induced in winding 20d is reduced so that a voltage is now impressed upon the condenser 18, via a suitably poled rectifier 21, to drive the control electrode 17c negative to make the valve 17 non- conductive causing relays 25, 27 to drop out thus returning the electromagnetic clutch to its normal condition to bring the conveyer to rest at a substantially predetermined position. The charge acquired by the condenser 18 prevents the re-starting of the conveyer until the charge has been dissipated. An electromagnetic brake may be used to assist the stopping of the conveyer.