Patent GB-190827242-A (GB)
Title: Improvements in or relating to Electrical Distribution Systems.
Inventor: CROUCH JOHN PEACHEY
Filed: 1908-12-15
Granted: 1910-03-15
Abstract: 27,242. Crouch, J. P., and Etchells, J. Dec. 15. Distributing. - In an electric distribution system containing a variable-speed generator and a battery, an electromagnetic switching arrangement is provided by which the battery and external circuit are disconnected from the generator, or the generator de - energized, when its voltage exceeds a predetermined amount. The battery then supplies the working circuit while the resistance in the circuit of the electromagnetic device responsive to changes of voltage is diminished, so that the dynamo may be connected up when the voltage of the battery falls to a predetermined value. A compensating - resistance is also provided which is inserted in the circuit of the voltage coil when the lamp circuit is open and the dynamo is charging the battery. In the arrangement shown in Fig. 1, the dynamo a is arranged to supply a a battery band lighting- circuit c. The field winding d is placed in a circuit containing a regulating- resistance e and . cut-out switch A across the dynamo terminals, the switch A being opened when the voltage of the dynamo exceeds a predetermined amount. A circuit containing the winding i of the switch B and the coil k of the switch C is placed across the dynamo terminals x, y, while a second circuit adapted to be placed across the dynamo terminals by the switch B contains a coil j, switch B, battery b, and coil k. Another circuit extends from the switch B through the resistance o, lead o', lamp switch p<1>, lamps c, lead o<2>, and coil k when the lamp switch p<1> is closed. The electromagnetic switching- arrangement for disconnecting the dynamo consists of the switch A, the coil u of which is controlled by a voltage coil q included in a circuit q<1>, which extends from a point 2 in the lead o' to a point q<2> forming one of the contacts of the switch C. From the contact q<2> the circuit continues to the contact q<3>, either by way of the contact k<1> of the switch c, or by way of the resistance s if the lamp switch p<1> is open, or by way of a circuit connecting the point 6 to the switch p<1>, and the switch p<1> to the contact q3 if the switch p<1> is closed. The contact q<3> is connected to the negative side of the circuit at the point 3 by way of the resistance r<1>. Assuming the dynamo a to be at rest, in which case it is arranged that the contacts q<2>, q<3> are short-circuited, a small current will flow from the positive terminal b<1> of the battery b to the contact m<2> of the switch B, through the movable contact n to the fixed contact m<1>, lead o', voltage coil q, contacts q<2>, q<3>, resistance r', coil k, to negative pole b<2> of the battery. If the lamp switch p<1> is closed, a circuit will also extend from the point 2 to the lighting-circuit c to the negative pole of the battery. Should the dynamo start and attain a speed sufficient to charge the battery when the lamp switch p<1> is open, the solenoid i of the switch B raises the contact n to bridge the contacts m, m', thereby connecting the dynamo a to the battery b through the coil j, while the switch C operates to insert the resistance s in the circuit of the voltage coil q. If, however, the switch p<1> is closed, the resistance s is short-circuited by the circuit from the point 6 to the switch p<1> and from the switch p<1> back to the contact q<3>. The switch B also connects the lamp circuit c to the dynamo through the resistance o. If the battery b is fully charged, and the dynamo exceeds a predetermined speed, the voltage coil q operates to close the circuit of the coil u of the switch A, which open-circuits the dynamo field circuit, thereby causing the switch B to disconnect the dynamo a. The switch C again short-circuits the resistance s, and the battery continues to supply the lamps until its potential falls below a predetermined amount, whereupon the coil q allows the switch t to open the circuit of the coil u, thereby causing the switch A to close the circuit of the field of the dynamo. In a two-battery system, the negative poles of the battery are connected, while one of the positive poles is connected to the contact m<2>, as shown in Fig. 1, the other being connected to the lead o'. In the two battery arrangement shown in Fig. 3, the switch B is dispensed with, and the terminal b<1> of the battery b is connected directly to the dynamo, while the second battery is connected on the lamp circuit side of the lamp resistance o, the other connexions being the same as in Fig. 1. When the dynamo is running at normal speed and voltage, the battery b is charged, and current is supplied to the lamp circuit c and battery b<3> through the resistance o. When the dynamo is at rest or cut out, the lamps are supplied directly by the battery b<3> and through the resistance o by the battery b. The batteries b, b<3> may be reversed in any suitable way when the direction of rotation of the dynamo is reversed. When applied to Stone's train lighting system, the switch A is arranged in the armature circuit of the dynamo.