GB237897A - Improvements in electrical control systems - Google Patents

Abstract

237,897. Forges et Ateliers de Constructions Electriques de Jeumont. Aug. 2, 1924, [Convention date]. Master control systems; controllers, actuating. - In controllers of the separate contactor type, the contactors are actuated by successive movements of two camshafts; the first shaft. which requires small power, acting upon movable parts of the contactor mechanism so as to form temporary rigid abutments, through which force is transmitted from the second shaft to close the contactors. Plane or helicoidal cams are employed. The shafts may be turned by ratchet and pawl mechanism actuated by electromagnets or pneumatic devices, and may be arranged for automatic progression under current limit control. For braking or reversing, in which contactors are operated in a different order from the normal progression, endlong movement of the cam-shafts is effected by electromagnetic means. Means are provided for latching the contactors after closure and for releasing the latches to allow the return strokes. Figs. 1, 2, 3 and 4 shows one of the contactors and its operating mechanism. The preparatory movement of a cam 15 on a rotary shaft g takes effect through a lever 17 upon two pivoted abutments 24, 29 both mounted on the contactor arm 1 and sets them in the path of rollers 13, 14 mounted on a rocking shaft 10. Successive to- and-fro movements of the rocking roller member close the contactor by positive action through the abutment 24 and open the contactor by releasing a latch 25 through the abutment 29. The intermittent rotary movement of the shaft g is produced by a ratchet b<3>, a pawl b<2>, and an electromagnet b. The rocking movement of the shaft 10 is produced by a crank or the like from an electromagnet e. Controlling switches for the magnet b may be arranged either for automatic or non-automatic advance of the shaft g. The cam 15 is fitted with a pin 25<2> which releases a latch 25<1> and thereby opens the contactor when the shaft b is returned to zero. Several cams are disposed on the shaft so as to close corresponding contactors in order for motor starting purposes; the return of the shaft b opening all the contactors. In a modification, an additional electromagnet returns the cam-shaft. In a further modification, one intermittently excited magnet is arranged to perform the double function of advancing the shaft g and rocking the shaft 10, and a compressible spring link actuates a safety switch in case the contactors stick or become blocked. A line circuit-breaker subject to automatic release may be closed by a linkage from the rock shaft. Diagrams of automatic and non- automatic control schemes are given, embodying series-parallel and electric braking features of known character. Specification 230,856. [Class 38 (i), Electric couplings &c.], is referred to.