GB148401A - Methods and circuit arrangements for generating pure continuous electric currents by means of machines - Google Patents

Abstract

148,401. Lorenz Akt.-Ges., C., and Schmidt, K. Feb. 13, 1919, [Convention date]. Converting alternating and direct currents. - Pure continuous current is obtained from a dynamo-electric machine by generating in the supply circuit a voltage that counteracts the undesired alternating currents impressed on this circuit by the machine. In the arrangement shown in Fig. 3, a transformer is used, whose primary winding S1 is connected across the terminals of the machine D, the secondary winding S2 being connected in circuit with the load V, which may be a microphone. A battery Z of primary or secondary cells or of polarization cells is connected in series with the winding S1, the voltage of the battery being equal but opposite to the continuous current voltage of the machine, so that only the alternating components of the current pass through the winding S1. The voltage induced in the winding S2 counteracts the alternating voltage directly impressed on this winding, so that pure continuous current is supplied to the load. An adjustable inductance may be inserted in series with the battery, or the battery and inductance may be replaced by a variable ohmic resistance. An auto-transformer may be used instead of a transformer with two windings. In order to compensate for the drop of voltage due to the ohmic resistance of the battery Z, an adjustable choking-coil r may be coupled with the field of the transformer and inserted in the supply circuit, as shown in Fig. 4. The coil r is adjusted until the disturbing alternating currents in the load V sink to zero, which may be ascertained by connecting a telephone receiver t across a portion of the load. The magnetic circuit of the transformer is preferably provided with an sir gap in order to limit its saturation by the continuous current. The Specification as open to inspection under Sect. 91 (3 )(a) states that a machine which generates the necessary counter-voltage may be employed instead of a transformer. This subjectmatter does not appear in the Specification as accepted.