Patent GB-190322758-A (GB)
Title: An Improved Voltage Regulated Electric System for Lighting Railway and other Carriages, for Ventilating, and Heating and other purposes.
Inventor: DALZIEL JAMES
Filed: 1903-10-21
Granted: 1904-10-21
Abstract: 22,758. Dalziel, J. Oct. 21. Dynamos, regulating. -Relates to a voltageregulated electric system for lighting railway and other carriages, in which power is derived from the axle of the vehicle which drives the dynamo, but which varies in speed. It is also intended for ventilating, heating, and other purposes. A standard source of potential, the pressure of which is substantially constant, is used, and this potential is balanced against the pressure generated by the variable-speed dynamo and impressed across the battery, if the latter is used. One or more armature windings are excited by this difference, so as to produce a counter-electromotive force, which varies in proportion to the rise and fall of the dynamo pressure, and is introduced into the dynamo field circuit, and in some cases into the main circuits also. Or the windings may be excited by balancing a substantially - constant pressure against that of the variable-speed dynamo in opposing exciting-coils. In the modification shown, the dynamo a is capable of running in either direction, b is a battery, and the constant-speed motor c drives a generator d mounted on the same shaft, on which is also mounted a small generator h giving a constant source of potential to serve as the standard, and which is in general a small shunt-wound machine, provided with a differential winding r<2>, but which may be constructed to be a second winding on the armature of the motor c. The motor c, controller d, and exciter h constitute the regulating-machines of the system. A n automatic pole-changing or reversing device of any known kind is used. The electromagnetic switch k consists of an arm y pivoted at z and connected to the core of the electromagnet v, having a fine winding w connected across the positive lead m<4> and the negative lead m<1>, and a thick winding x in series with the lead m<4> and connected to a contact k<1>. The switch carries bridge-pieces k<9>, k<6> and a contact k<3>, and moves over contacts k<4>, k<5>, k<7>, k<8>. The main switch l consists of an arm l<3> pivoted at l<9> and provided with bridge-pieces l<4>, l<5>. It moves over contacts l<1>, l<2>, l<6>, l<7>, l<8>. The parts are connected together as shown, namely, the dynamo negative terminal t<2> to the battery at s<3>, to the negative terminal of the lamps n or other translating-device, to the negative terminal t<4> of the regulating-machines, and to the negative terminal t<5> of the shunt winding of the dynamo a. The positive terminal t<1> is connected by the heavy lead m<4> to the switch k, and carries the current to the battery and to the lamps. When the dynamo is not in action, the switch k is in the position shown in full lines, the positive terminal t<6> of the main dynamo shunt winding being connected through the lead m<7>, contact k<5>, bridge-piece k<6>, contact k<4>, leads m<16>, m<5>, contact k<1>, coil x, lead m<4>, and terminal t<1> to the dynamo. When the dynamo is in action, the current passing through the fine coil w raises the core of the electromagnet v and the arm y. In this position, the current passes from the contact k<1> to the contact k<2> by the bridge-piece k<9>, and thence by the lead m<8>, contact l<1>, and lead m<9> to the battery b, which is thus connected directly across the terminals of the dynamo a. Should current begin to pass from the battery to the dynamo from any cause, the current through the coil x will demagnetize the electromagnet v, resulting in the circuit across k<1>, k<2> being broken. As the arm y rises, current flows from the lead m<5> to the contacts k<3>, k<7>, lead m<10>, contact l', lead m<11>, terminal t<10>, winding e of the controller, and terminal t<8> of the exciter h. As the arm y rises, the contact k<5>, connected to the shunt terminal t<6>, is also connected to the contact k<8>, and thence by the lead m<12> to the terminal t<9> of the winding f of the controller. The motor c is connected from the terminal t<10> across to the terminal t<4>. The effect of this is that the regulating-machines start running, and that the windings e, f are inserted in series with the field circuit of the dynamo a. If the switch arm l<3> be put in any operative position when the dynamo is not in action, the lamps &c. and the regulating-machines will be supplied with current from the battery. The bridge-piece l<5> has a long contact so as to supply current through both contacts l<7>, l<8> or through only one, as desired. As shown, the lamps are connected in two circuits, but they may be otherwise arranged If no battery is used, the contacts k<2>, l<1>, l<2> and bridge-pieces l<4>, k<9> are unnecessary. The current to the lamps &c. is supplied through the armature winding of the controller d both from the dynamo and the battery. The controller d may be formed as two machines, and the exciter h may be duplicated. The windings e, f may be arranged so that the winding e carries the current to the lamps &c., and the winding f to the dynamo field coil. A shunt resistance may be provided across the coil g to vary the maximum voltage. A coil connected across the constant-potential mains and wound on the field magnets of the controller may be used instead of the dynamo h. Such an arrangement is shown in Fig. 2, wherein the two coils r<3>, r<4> replace the coil g, Fig. 1. The coil r<3> is connected across the constant-potential supply circuit, and the coil r' is connected across the main generator terminals by the leads m<11>, m<2>. The two coils are wound so that, when the generator a is giving a pressure equal to that required for the lamps &c., their effects balance. In another modification, for use where the lights never vary, the winding e is omitted, and a resistance is connected in each lamp circuit. Contacts are provided on the switches k, l for short circuiting the resistances when the dynamo becomes inactive. In another modification, the motor c may run as a generator under certain conditions.