GB190425112A - Improvements relating to Electric Light Systems - Google Patents

Abstract

25,112. Lake, H. H., [Gould, C. A.]. Nov. 18. Dynamos, regulating.-Relates more particularly to automatic regulating-apparatus for maintaining a substantially-constant current in electric lighting systems in which the generating-dynamo is subjected to great variations of speed, as, for example, when the dynamo is driven from a car axle in a railway-car lighting system. Means are also provided for increasing or decreasing the excitation of the dynamo according as the load in the working circuit is increased or reduced. The field windings of the main generator A, which charges a storage battery B<1>, are excited by a small shuntwound dynamo E driven by a motor D, the field magnets of which are fed with current from an auxiliary dynamo C, the armature of the latter being mounted on the generator shaft a, which is coupled by a belt &c. with a car axle. The field circuit of the dynamo C is connected with a source of constant current, such as the battery B<1> or the working circuit, by means of a two-way switch c<3>, while the motor armature is arranged in the working circuit. When the armatures of the dynamos A, C reach a predetermined slow speed, the motor D is switched in by an electromagnetic switch F, and the dynamo E excites the field winding of the main generator to its maximum value, enabling the generator to furnish its full output. As the speed of the generator increases, its field excitation decreases in a greater proportion, and vice, versÔ, thereby compensating for the varying reluctances of the magnetic circuits. The generator is connected to the battery B<1> through a switch G operated by a shunt solenoid g, and a series coil g<1> serves to retain the switch in a closed position until the generator electromotive force drops below that of the battery, when it acts in opposition to the solenoid g and causes the circuit to open. By connecting the auxiliary dynamo C across the battery terminals, the generator electromotive force is made to vary with that of the battery. An electromagnetically-controlled rheostat H, or counter-electromotive force cells, &c. are employed for regulating the electromotive force across the mains, and, in order to further vary the excitation of the generator in accordance with the load on the working circuit, the exciter E may be provided with a third field winding E<3>, Fig. 2, in series with one of the mains.