Patent GB-190714725-A (GB)
Title: Improvements in or relating to Electrical Potential Regulators or Speed Controlling Devices.
Filed: 1907-06-26
Granted: 1908-01-30
Abstract: 14,725. Siemens Bros. Dynamo Works, Siemens-Schuckertwerke Ges.]. June 26. Regulating; switches.-A regulating-device has a vibrating tongue which puts a resistance in or out of circuit under the influence of a potential relay. Suitable arrangements of one or two electromagnets or mechanical oscillating devices are described. The field e of the generator g, Fig. 1, is supplied from an exciter g', the field winding n of which is connected in series with a resistance w. This resistance is intermittently short-circuited by the vibrating tongue h and the contact c. The solenoid s pulls down the tongue h against the pull of the spring f. When the contact between the tongue h and contact c is broken, the potential of the exciter g' drops, thereby decreasing the pull of the solenoid s, and when contact is made the potential is increased. A relay in the circuit of the generator g may be used to adjust the spring f; or, as shown, it may be used to adjust the position of the contact c and so vary the sensitiveness of the device. A dash-pot d may be employed to prevent the tongue -h from moving too far. The electro-magnet s and spring f may be replaced by two otters m<1>, m<2>, Fig. 2, which are connected in parallel with each other to the source z, the former being in series with a non-inductive resistance o, and the latter in series with an inductance l. A resistance i is connected in the common circuit of the two windings, and is short-circuited by the vibrating tongue h and the contact c<1>. As the tongue vibrates, the variation of the current due to the insertion and short-circuiting of the resistance i is more marked in the coil m<1> than in the coil m<2>, so that the vibrations will continue after teing once started. A potential relay r opposed by a spring q is arranged to vary the time during which the tongue hand contacts c<1> are in contact. The exciter is regulated as in Fig. 1 by the intermittent short-circuiting of a resistance w by the tongue h and contact c. The resistances i, w may be combined as one resistance, and may be short-circuited through relays instead of directly by the tongue h. The inductance l may be replaced by the winding n. If generators in parallel are separately regulated, known means, as for instance those described in Specification No. 15,035, A.D. 1906, are used to prevent opposing currents from arising. The electro-magnet m<2> may be replaced by a spring, and this may be combined with the spring q to act as a single spring. The other electro-magnet m<1> may then be connected in parallel with the winding n; or, a separate circuit may be provided for it, as shown in Fig. 5. The tongue h periodically shortcircuits the resistance o, and so avoids sparking at the contact c ; or, a condenser may be used to prevent sparking. The windings m<1>, r may be connected in series on one core, and connected in series with the relay u. The speed of a motor may be regulated by connecting a small generator to the winding r and coupling it to the motor. In all the above modifications, the tongue operates by its natural vibration, but it may be mechanically vibrated. A crank k, Fig. 7, acts through an elastic connexiori l to vibrate the tongue h, the duration of the contact being limited by the relay r. The crank may be replaced by an electromagnetic system with a constant oscillation period.