Patent GB-395520-A (GB)
Abstract: 395,520. Charging batteries; regulating dynamos. KELLETT, W. P., 4457, Waldo Avenue, Fieldston, New York, U.S.A. July 23, 1932, No. 20797. [Classes 35 and 38 (iv).] Regulation,. automatic.-A battery-charging system for lighting &c. on a vehicle comprises a reversible generator A driven from the road wheels and automatically connected to the battery E only when the vehicle is descending an incline, provision being also made for an over-riding control of the connection subject to the minimum charge in the battery. The equipment comprises gradient responsive hydraulically operated switches J, K which, in conjunction with a switch H the windings 37, 38 of which are responsive to the direction of movement of the vehicle, and through a relay 71 control the energization of a relay 70 which cuts out a voltage limiting resistance 48 from the generator field circuit so as to raise the generator voltage above the battery voltage and so cause closure of the main relay operated switch C between the generator and the battery. An ampere-hour meter 80 in the battery circuit has cam operated contacts 79, 81 which can close the circuit of the relay 71 independently of the gradient and direction responsive switches J, K, H so that the relay 70 may be energized when the battery charge falls too low. Switches J, K each as shown at K in Fig. 3 are arranged, one at each end of a fluid-filled pipe 13 arranged lengthwise of the coach. The tube 13 is filled with mercury or other fluid and connected at each end to a cup 2 sealed by a flexible rubber. diaphragm 8 on which rests a light aluminium plate 9 to which is secured a bellows 10 enclosed in a cap 3 flanged at 5 so as to limit the maximum displacement of the plate 9. A light fluid, such as oil, in the bellows 10 is connected by a pipe 18 to a chamber 17 enclosing a similar bellows 19 connected to a rod 20 which operates a spring- controlled snap switch 24 so as to connect the terminals 25, 26 of the switch J or K as the case may be. The generator A, Fig. 4, is provided with two brush rings b, d mounted on a ring e rotatable, between stops f and g where it is arrested by a lug h, by the friction of the brushes on the commutator so as to maintain constant the polarity of the rings band d respectively irrespective of the direction of rotation of the generator. The ring e is provided with a stud n which connects together either contacts o, p or q, r according to the direction of travel of the vehicle, so to energize one or other of the windings 37, 38, Figs. 1 and 6, whose armatures are connected in a pivoted framework whose arms 33, 39 are pivoted on a bracket 34 and are controlled by two springs 40. The rocker arm 33 is provided with roller contacts 35 at each end so as to bridge either of two pairs of contacts 30, 301, 31, 31<1> according to the direction of travel of the vehicle and thus rendering the circuit of one of the switches J, K operative so that only when the vehicle is descending an incline is the relay 71 energized. When the carbon resistance 48 is cut out by the relay 70 the generator voltage and output are regulated by current and voltage coils acting on an armature 57 to compress a carbon resistance 46. The cut-in switch C has two solenoids acting on a common armature and is provided with shunt coils 60, 61 in series with each other and assisting each other and a series coil 58 in their action on the armature 63, and a coil 62 connected between the moving and fixed contacts of the switch C so as to respond to the difference between battery and generator voltages and to oppose the other coils of the switch. When the switch C is closed part of the shunt coil 60 is short-circuited by an auxiliary contact so as to render the switch more sensitive to current reversal. Manually operated switches 88, 83 connect the generator system to the battery and to the load.