GB515498A - Starting apparatus for prime movers and the like - Google Patents

Abstract

515,498. Starting prime-movers. WINTHER, M. P. June 3, 1938, No. 16722. Convention date, Nov. 22, 1937. [Class 38 (iv)] [Also in Group XXVII] In starting apparatus for prime-movers a manually closable switch normally biassed to the open position is adapted when closed to energize a circuit controlling the energization of an electromagnetic clutch coupling an electric starting motor to the prime-mover, the circuit of the motor being closed automatically after the clutch circuit is closed and the manual switch being held closed under the heavy starting current conditions of the motor but being automatically reopened to open the clutch when the starting current decreases on the starting of the prime mover. A prime mover 1 driving a dynamometer 3 for test purposes is started by an electric motor 9 to which it is connected by an electromagnetic clutch 7 and a chain and sprocket drive. Closure of a push button switch 131, 111 energizes 'a relay 107 which closes contacts 93 and energizes the clutch coils 25 from D.C. supply in series with a further relay 103. After the clutch is closed relay 103 operates and closes contacts 81 which causes energization of a contactor 73, 69 to connect the starting motor 9 to A.C. mains. A current coil 65 in series with the starting motor holds the switch 111 closed until. due to the prime mover starting, the starting current falls. Contacts 111 then open, relay 107 de-energizes and close contacts 121 which complete a discharging circuit for the electromagnet coil 25. The motor and the electromagnetic clutch are de-energized. In emergency, a push button switch 133, 117 in series with switch 111 may be opened to cause de-energization of the motor 9 and opening of the clutch 7. A reversing switch 71 is provided to permit starting jn either direction. The engine shaft 13, Fig. 3, is coupled to the rotatable casing of the dynamometer 3 and is keyed to a magnetic plate 21 forming one member of the clutch. The end of the shaft 13 is carried in the hub 6 of a rotatable casing 17 bolted to a sprocket 19 the hub 23 of which carries the coils of the electromagnetic clutch. The sprocket 19 is coupled to the motor shaft by a chain drive and the hub 23 is journalled on a stationary hub 29 bolted to a sleeve 33 supported on pillars 39. The hub 23 is movable axially against the action of springs 43 mounted on pins 47 slidable in the hub 23 and carried at their other ends by a ring 49 bearing against a flange 51 on the stationary hub 29. Connections from the electromagnets are taken to slip rings 55 on the hub 6.