Patent GB-156303-A (GB)
Title: Improvements in electric generating plants
IPC: H02P9/00
Filed: 1919-09-24
Abstract: 156,303. Austin Motor Co., Ltd., and Walker, C. B. Sept. 24, 1919. Regulation, automatic systems and apparatus for; systems of charging and discharging galvanic batteries.-In an electric supply system comprising a petrol engine, a three-brush dynamo-electric machine, adapted to operate as a starting motor, a battery circuit and a load circuit, the voltage of the load circuit is controlled by varying the position of its positive brush relative to the fixed positive brush of the battery circuit, and the negative brush of the machine is lifted from the commutator and the ignition circuit broken when the battery is fully charged, or when the engine stops during the charging period. The positions of the brushes are controlled by means of a reversible electric motor controlled by a voltmeter or by a hand-actuated switch. The commutator G, Fig. 1, of the dynamo-electric machine is provided with a fixed-positive battery brush b, a rotatable positive load-circuit brush b<1>, a negative brush b<2>, and ignition circuit brush i adapted to be lifted from the commutator G and a ring connected to a commutator segment when the battery is fully charged, and a fixed field circuit brush f. The position of the brush b<1> and the lifting and lowering of the brushes b<2>, i are controlled by a reversible motor M, the circuits of the field windings m, m<1> of which are controlled by a voltmeter V connected across the load circuit P, P<1>, an electromagnetically or hand-actuated switch J, and relays R, R<1>. The motor circuits are broken at the end of the operation by means of a switch 52<a>. The brushshifting mechanism operated by the motor M comprises spur-gearing 7, 8, Fig. 4, worm-gearing 11, 12, Figs. 3 and 4, worm-gearing 15, 16, the element 16 of which is fast on a drum 17 containing a resilient coupling in the form of a spring 18, Fig. 6, connecting the drum 17 with a disc 19 secured to a sleeve 20 carrying a pinion 21 engaging a rack 22 upon an annulus 23, Fig. 2, carrying an arm 26 upon which the brush b is mounted. The limiting positions of the arm 26 are determined by a fixed stop 27 and an adjustable stop 28. To raise or lower the brush b<2> after the arm 26 has reached the stops 28 or 27, the drum 17 is provided with a projection 29, Figs. 6 and 7, and the disc 19 with a projection 30. These projections are placed between a projection 31 upon a flanged sleeve 33 and a projection 32 upon a flanged sleeve 34. The flanges of the sleeves 33, 34 are provided with recesses through which the ends of the spring 18 pass. This arrangement allows the shaft 35, to which the drum 17 is keyed, to rotate after the arm 26 engages its stops 27 and 28. The shaft 35 carries a disc provided with a crank pin and cams 51 and 52, Fig. 2. The crank pin is connected to a lever 40, secured to a shaft 41, by means of a telescopic connecting rod 39 containing a spring. The lever 40 is integral with a plate 44 provided with notches 45, 46 adapted to be engaged by a pin 47 mounted upon the arm 48 of a bell-crank lever 48, 50. The rotation of the shaft 35 in one direction compresses the spring of the connecting-rod 39 until the cam 52 engages the arm 50, when the pin 47 is released from the notch 45 and the shaft 41 is given a quick movement limited by the pin 45 engaging the notch 46. This movement of the shaft 41 raises the brushes b<2>, i through levers 42, 43, Fig. 4. When the shaft 35 rotates in the opposite direction, the spring in the connecting-rod 39 is tensioned until the cam 51 engages the arm 50, when the shaft 41 is released to lower the brushes b<2>, i. The switch 52a, which breaks the circuit of the motor M, consists of a conducting plate 53, Figs. 2 and 8, with insulating portions 54, 55 adapted to come under the brushes 58, 59 to break the circuit.