Patent GB-191324306-A (GB)
Title: Improvements in and relating to the Conversion or Transformation of Electric Current.
Inventor: ARTHUR SCHERBIUS
IPC: H02K29/00
Filed: 1912-10-25
Abstract: 24,306. Scherbius, A. Oct. 25, 1912, [Convention date]. Void. [Published under Section 91 of the Act.] Are and spark-gap apparatus, arrangements of; vapour and vacuum or low-pressure apparatus, arrangements of; systems for conversion, employing rotary converters or rotary transformers. - In current-converting apparatus, arcs, vapour lamps, or vacuum rectifiers controlled or operated by means of variations of temperature or ionization are employed instead of the usual commutators or collectors. When mercury-vapour arcs are used, the circuit may be closed by heating the cathode by means of a controlling-current from an auxiliary anode. The circuit is opened by cooling the cathode by diminishing the current from the auxiliary anode, the cooling being assisted by means of evaporating liquid or by embedding the cathode in a good conductor of heat. When a sparkgap between arc-lamp carbons is used, the circuit is closed by means of high-tension current and opened by blowing out the arc with air or by means of a magnetic field. In Fig. 2 is shown the application of the invention to an electric motor having a rotating armature excited by direct current and a stationary part with a number of windings connected on one side to a star point and on the other side to electric valves in a mercury-vapour tube by means of which the windings are connected and disconnected in succession. Where an even number of windings is used, the windings are so arranged that each winding traversed by a current is adjacent to a winding which is currentless at the time, in order that the heating and magnetic effects in the machine may be uniformly distributed. The windings may be provided with valves at each end arranged for each direction of current flow. In the arrangement shown in Fig. 4, which may be used for converting direct current into alternating current, two tubes I, II, each with a cathode and a series of anodes, are employed, the tube I controlling the continuous current coming from the net, while the tube II short-circuits windings at right-angles to the windings controlled by the field I, thus producing a field which constantly compensates the direct-current net voltage. An additional polyphase winding is used to take off the alternating current. The periodicity of the current depends on the speed with which the valves are operated, and its voltage relatively to that of the direct current may be regulated by means of separate windings or by a winding having separate tapping points. In another application, the secondary set of valves in the tube II may be connected to a shunt or series direct-current motor for starting and regulating, the valves being controlled by another apparatus running synchronously with the motor. The arrangement shown in Fig. 4 may also be used for converting direct current of one voltage into direct current of a different voltage, or for converting polyphase current into continuous current. High voltages may be produced in a single machine by connecting the windings in series, as shown in Fig. 5. A method of producing high-frequency currents is shown in Fig. 8, in which a coil r in series with a tuned oscillatory circuit k is moved into and out of a field generated by a coil s in series with the coil r, a controlled valve v being placed either in series or in parallel with the coils. An auxiliary circuit k may be provided in order to prevent the complete interruption of the current. The application to a machine with multiple poles is shown in Fig. 9, r being the rotor and s the stator. The machine may also work as a high-frequency motor or as a transformer.