Patent GB-311201-A (GB)
Title: Improvements relating to power generation and transmission systems
IPC: H02P9/00
Filed: 1928-02-02
Abstract: 311,201. English Electric Co., Ltd., and Caldbeck, C. J. Feb. 2, 1928. Dynamos and motors combined for transmitting power; charging batteries; supplying consuming devices from variable-speed generators. - In a power generating and transmitting system for driving vehicles, or for loads of any character, in which an overload-responsive device disconnects the generator from the load, means are brought into operation by this device to reduce the speed of the prime mover below that at which it is running when the device operates. A storage battery may be charged by the exciter when the system is on load, but at the reduced speed it may be automatically connected to the main generator, whereby a heavy boosting charge may be given. According to the Provisional Specification, the exciter may be used for charging when the prime mover is running light. A generator 1 is connected through a line-breaker 3, a reverser 4, and overload responsive means 7 to a load 2 comprising, for example, one or more motors driving a vehicle. The generator 1 and an exciter 5 are driven by a former mover. such as an internal-combustion engine, controlled by a number of electromagnetically-operated valves A - - D, of which A is closed and the remainder opened when energized. With the prime mover at idling speed, valve A being open, a reversing switch 10, interlocked with a controller 9, is thrown to one of its operating positions. This connects a battery 6 through a series field on the exciter 5, contact 24 in the overload responsive device 7, and " deadman's handle " 16 to the contact of the controller 9.. In the first load speed position I controller 9 extends this connection to the coils of valves A and B and completes a circuit energizing the appropriate reverser coil 18, 19. The contacts of the reversing switch 10 are interlocked electrically with auxiliary contacts on the reverser 4, which are in circuit with the closing coil 8 of the linebreaker. When the reverser 4 has operated it therefore completes the circuit of closing coil 8. Auxiliary contacts k, n on the line breaker 3 complete respectively the circuit of valve coils A and B and a retaining circuit for coil 8. The prime mover then drives its load and the controller 9 is moved to positions II and III to increase it; it cannot be speeded up until it has been placed on load. The storage battery 11 is automatically connected to the exciter for charging at load speeds by a switch 11 energized by the usual cut-out with shunt and series coils 12, 13; at idling speed the exciter voltage is inadequate to charge the battery and the switch 11 is then open. Upon overload the contact 24 of the overloadresponsive device 7 opens and the valve coils A - - D and the line-breaker coil are simultaneously de-energized. Thus even should the linebreaker 3 stick in the prime mover will be reduced below its load speed by the closing of the valves B - - D and maintained at idling speed by the opening of valve A. To reset the overload device the controller 9 has to be restored to idling position and a switch 25<a> closed, this completing the circuit of resetting coil 25 if the linebreaker, being open, has closed its auxiliary contact p. When the line-breaker 3 opens it closes auxiliary contacts l, n in the circuit of a coutactor 32 by which the generator 1 may, at idling speed, be connected automatically or at will to the battery 6, through an adjustable resistance 31, as determined by a switch 35.