Patent GB-190608717-A (GB)
Title: Improvements in Supplying, and Controlling the Voltage of, Electric Currents from Variable Speed Generators; specially applicable to Railway Carriages and the like.
Filed: 1906-04-11
Granted: 1907-04-18
Abstract: 8717. Veritys, Ltd., and Dalziel, J. April 11. Dynamos, regulating.-Relates to apparatus for supplying and controlling the voltage of variablespeed railway-carriage &c. generators and of the type of the last modification described in Specification No. 22,758, A.D. 1903. The current-supplying means comprises a storage battery Wand a main generator D having regulating-means consisting of a motor F, controller G, and an exciter E, with their three armatures mounted on the same shaft. The exciting-coils of the auxiliary machines are so connected that, as the speed of the main generator rises, a counter-electromotive force provided by the controller armature, which is in series with the main generator field winding across the line, also rises and reduces the current in the main field winding. To increase the sensitiveness of regulation, the connexions of the motor F are so arranged that, as the voltage of the generator rises, the speed of the motor F, and therefore the speed and the voltage of the exciter E, are reduced, thereby still further increasing the counter electromotor force of the controller. The brushes D1, D2 of the dynamo D are connected to a reversing-switch c, the arm of which is moved so that a terminal P is always connected to the positive brush and a terminal N to the negative brush. The shunt winding D3 is connected at one end to the terminal N, and at the other to a terminal S, which is connected through the controller armature and also through a solenoid h on a switch B to the terminal P. The exciter E is connected across the line in series with the controller field-magnet winding g and the motor field-magnet winding f. The shunt field e of the exciter is connected in series with a voltage-regulating rheostat R, and by way of the terminals Pa, Pb it is connected, when a switch A is closed, through a flexible coil t and contact m2 to a terminal P2 connected to P. When the switch is open, the connexion is made through the starting-resistance T. The controller G is connected to the terminal S and through the terminal P1 to the terminal P. The motor F is connected between the terminals N1, Pa, and has a second field winding in shunt across the line from P1 to N1. The voltage of the exciter is adjusted to that normally required from the dynamo D. In the arrangement shown in Fig. 1, the current in the controller field-magnet winding g is proportional to the difference between the exciter voltage and the line voltage, and, when these are equal, no counter-electromotive force will be developed by the controller. The switches A, B for cutting in and out the main generator are operated by solenoids k, l, h, and remain in the position shown when the solenoids are not magnetized. The solenoid k is connected across the terminals of the generator through the terminals P2, N2. A switch v and resistance x are provided, the switch being raised and resistance cut in by the rising of the plunger of the switch A, thus preventing undue heating of the coil k. A series coil l is brought into operation when the switch A is closed, and is connected to the terminal P2 through contacts m1, m3 and at the other end to the contact Pc, and thence to the switch o of the lights. The solenoid h is connected across the controller G. The switch B has four contacts n1, n2, n3, n4, of which the first is connected to the battery positive lead q, the second to the dynamo line P1, the third to an electro-magnet d and thence to the positive lead q, and the fourth to the battery lead connected to the lamps L. The lamps are arranged in two sets, each having separate positive and negative leads p1, p2 and na, nb, but a common battery positive lead q. The leads P1, p2, na, nb are connected to the bar switch 0 shown, so that the lamps may be disconnected or one set may be put in circuit as shown. When the lever o1 is turned so that the contacts o3, o4 are connected to the contact o2 and therefore to the terminals N3 and N, and so that the contact o6 is connected through the contact o5 to the positive leads p1, p2, both sets are cut in. The lamps are provided with separate switches M, which connect them between the negative leads and the battery, or between the negative leads and the dynamo positive leads pi, p2 through resistances H. When the generator is at rest or rotating at too low a speed, the lamps are connected across the battery through the terminal Q1, magnet d, contacts n3, n4, terminals Q2, lead q, switches M, lamps L, leads na or nb, terminals N3, N, and the battery negative terminal N4. When the speed of the generator rises, the coil k becomes energized sufficiently to close the switch A, and the generator is connected to the lamps through the terminals P2, Pc. As the generator voltage rises, the lamp load is picked up by the generator, the battery current diminishes, and the voltage of the controller at length rises enough to energize the solenoid h and raise the switch B.in opposition to the magnet d. The battery is then disconnected from the lamp circuit, and connected across the dynamo leads for charging. Fig. 2 shows a simplified form of the connexions of the auxiliary machines.