Patent GB-475378-A (GB)
Title: Improvements in and relating to self-contained electric generating systems
IPC: H02P9/00
Filed: 1936-10-10
Abstract: 475,378. Supply systems for consumption apparatus; starting prime movers. GIL, J. V., and KOHLER CO., Ltd. Oct. 10, 1936, No. 27568. [Class 38 (iv)] In a self-contained electric generating system adapted to start and stop automatically in response to load requirements and including a generator with series and shunt field windings, which supplies the load circuit directly and a battery of lower voltage which is used for starting an internal - combustion engine driving the generator, the connections between the generator armature and the series field winding are transposed upon the demand or the cessation of demand for current from the generator. The generator 1 is provided with a shunt field winding 11 and a series winding 8 which is reversed by switch 3 according to whether the generator is supplying the load leads 38, 27 or is being operated at lower voltage by current from the battery 17 for starting. When a load is switched in, the battery 17 supplies current to coils 23 and 22 which operate switch arm 21 to engage contact 20 by which a circuit is completed from the battery through contact 16, contacts 49, which are closed when the engine is not running, relay 15, thermal time switch 48, contacts 46, 47 and contacts 20, 21 to battery lead 2. Relay 15 closes contacts 14, 16 so that current from the battery is then supplied to the engine through series field 8 and lead 6 to switch 3. At the same time battery current is supplied from contact 16 to contact 50 energizing thermal switch 48 which opens the circuit through relay 15 if the engine fails to start. When the engine starts, the current generated being at a higher voltage than that of the battery, energizes relay 5 which operates switch 3, thus reversing the direction of the current through the series field 8. Relay 5 also closes switch 37, thus energizing relay 31 to close contacts 24, 25 so that current flows from the generator to load lead 27. As this current traverses winding 22, contacts 20, 21 remain closed. Relay 31 also opens contacts 46, 47 thus de-energizing relay 15 and cutting off the current supply from battery to generator if this has not been done previously by the opening of centrifugal or like contacts 49 by the running of the engine. The battery is charged by the generator through resistance 28, part of which may be cut out. When the load leads 27, 38 are relieved of all load, relay switch 21 is de-energized thus closing contacts 35, 39 through which current from the generator passes to relay coil 40 opening switch 42 and closing switch 43. Battery current from contact 16 through switch 43 then energizes relay 44 cutting off fuel. Relay 44 is restored automatically to the closed position after an interval sufficient to ensure that the engine has stopped. Although winding 40 is de-energized by the opening of switch 42, switch 42 and 43 are not returned until after a certain interval. Stoppage of the generator de-energizes relay 5 and switch 3 then returns reversing the connections of field winding 8 ready for re-starting. Switch 37 is also opened, de-energizing relay 31, so that contacts 24, 25 open and contacts 46, 47 close in readiness for a re-start. If switch 58 is opened, the engine may be started by hand. Failure of lubricating oil pressure or overheating of engine result in the closing of switch 53 through which relay winding 40 is energized to stop the engine. This emergency stop circuit is completed through indicating relay 54 which opens contact 56 in the battery connection so that the engine cannot be re-started until contacts 56 are re-set by hand. Relay 5 may be operated only by current from the battery during starting, the connection being reversed by a spring when the battery current supply to the engine is cut off.