GB130936A - Improvements in or relating to Rectifiers for Alternating Electric Currents. - Google Patents

Abstract

130,936. Hartmann, J. F. G. P. Nov. 14, 1918, [Convention date]. Commutator switching-arrangements. - In a rectifier for alternating currents, of the kind comprising a mercury or other conducting-liquid jet S passing through a magnetic field M and striking an electrode E, as described in Specification 102,977, an auxiliary source of current is inserted in parallel with the jet S in a circuit which includes a commutator, preferably comprising a subsidiary jet s traversing a field m, adapted to complete the circuit during the period in which the electrode E is impinged upon by the rectifying jet S. The auxiliary current maintains the motion of the jet independently of the rectified current, and permits the regulation of the rectified current to valves approaching zero. When the rectifying jet carries alternating current, the auxiliary current must be in phase with the current to be rectified and may be obtained from the same source as the main current through a separate transformer, as shown in Fig. 1, or by tapping the main transformer winding. In the arrangement shown in Fig. 3, the jet is alternately connected to half windings V<1>, V<2> of the transformer used and carries direct current. The auxiliary current is in this case supplied by a battery B, the fields M, m being alternating and supplied from the windings V<1>, V<2>. In a modification, batteries are placed in the leads connect. ing the subsidiary electrodes e<1>, e<2> with the main electrodes E<1>, E<2>. In the arrangement shown in Fig. 5, separate rectifying jets S<1>, S<2> are used for each half of the transformer winding, the auxiliary current being obtained from a battery B through a jet s traversing an alternating field m supplied with current from the same source as the current to be rectified. For rectifying polyphase currents, a rectifier with rotating field is used, as shown in Fig. 6, the auxiliary current being obtained from a battery B.