Patent GB-191017995-A (GB)
Title: Control Devices for Electric Cars on Routes in which Two Different Voltages are Supplied.
IPC: B60L9/30
Filed: 1910-07-28
Granted: 1911-03-16
Abstract: 17,995. Siemens Bros. Dynamo Works, [Siemens Schuckertwerke]. July 2 Changing from one voltage to another.-In systems of electric traction in which the cars are driven by current at different voltages when in different track-sections, the controller governing the direction of travel of the car makes, or causes to be made, all the readjustments in the control circuit that are necessary in changing from one voltage to another. The control circuit is led through the said controller for this purpose. The invention is illustrated as applied to a system supplied with current at voltages in the ratio 2:1, in which the motor-controller consists of separately-actuated electro-magnetic switches 69 ... 83, and in which the. control circuits are governed by a relay 35 which, being permanetly connected between the main motor current lead 5 and earth, puts into operative connexion a lead 50 when the supply is of low voltage and a lead 51 when the supply is of high voltage. In order to render the motor-controller 69 ... 83 inoperative until the other necessary readjustments have been made, the direction-changing switch 32 carries contacts 20 ... 23 arranged to connect the leads 50, 51, respectively, to the lead 85 that carries the control current from the motor-controller. This controller is, as usual, governed by a master-controller 39 through which its operating-current passes. The direction-changing switch has four positions: two for 600-volt operation, forward and backward, and two for 1200-volt operation, forward and backward. In the first two positions, contact 22 or 23 closes the control-current circuit to the relay switch through the lead 50; in the second, contact 20 or 21 closes it through the lead 51. The readjustments referred to are (1) changing the arrangements of the automatic releases, for example, from a series connexion of two circuitbreakers for high voltage to parallel connexion for low voltage; (2) changing the value of the resistance 36, 37 in series with the motor-controller. These readjustments are effected as follows. Contacts 24, 25, 28, 29 on the direction-changing switch 32 throw the automatic releases 3, 4 into parallel in either of the first two positions, and the contacts 26, 27 put them in series in the remaining two; contacts 30, 31 short-circuit the resistance 36 in both low voltages positions. Contacts 18, 19 are the usual reversing-contacts controlling the leads 89, 90 to the reversing-switches. The relay 35 may have an additional switch member 91 controlling a solenoid 95, which works against a spring 97 to operate a drum switch 96 to rearrange the lighting and heating circuits according to the supply voltage. With voltage relations other than in the ratio 2:1, suitable changes are made in the arrangement of the circuit-breakers 3, 4, for instance by using separate actuating-coils suitably wound, or one coil with an intermediate terminal which is employed at the lower voltage. To prevent the driver from setting the master controller 39 on the " four motors in parallel '' contacts, which are not used on 1200-volt operation, a stop or other suitable mechanical device may be arranged on the direction switch to act upon the master controller.