GB137522A - Improvements in electric power systems - Google Patents

Abstract

137,522. Domestic Engineering Co., (Assignees of Kettering, C. F.). April 6, 1918, [Convention date]. Lighting and heating systems.-Relates to electric power systems of the type which comprises a generator driven by an internal-combustion engine and supplying current to a storage battery and also capable of acting as a motor to start the engine. According to the invention, a portion of the battery furnishes current for ignition, and simultaneously the remaining portion of the battery is caused to discharge at the same rate. The Figure shows one arrangement. An internalcombustion engine 20 drives a compound-wound generator 30 which feeds a battery 40 composed of fifty-six separate cells. The ignition circuit includes sixteen cells and may be traced from the cell terminal through switches 62 and 66, induction coil primary 72, rotary interrupter 76, and ammeter 51 to the positive battery terminal. A discharge path for the remaining portion of the battery is provided from the point 69 through a resistance 81, switch 43, and line 41 to the negative pole of the battery. The resistance is so chosen that the rate of discharge of the cells included in this circuit is equal to that of the cells included in the ignition circuit. For the purpose of starting the engine, switches 62, 43, and 66 are closed, completing the circuits described above and opening a normally closed switch 53, 54, whereby the series field of the generator becomes active and connexions are made for causing the machine to run as a motor. When the engine has started, the closing handle of the switches 43 and 66 is released, the switches being magnetically held on by a coil 106, while the switch 53, 54 closes again and short-circuits the series field. The ignition and charging functions then proceed normally. To prevent back discharge of the battery through the generator when the engine stops, a magnet 103 is, in this case, adapted to release a contact 100 and thereby open-circuit the holdon coil 106, thus allowing switches 66 and 43 to open. A double-pole switch 116, 117 is provided for making connexion to the external work circuit.