GB472706A - Improvements in and relating to rotary commutator switching apparatus for convertingelectric currents - Google Patents

Abstract

472,706. Mechanical make-and-break switches; high - tension switches. SIEMENS-SCHUCKERTWERKE AKT.-GES. April 27, 1936, No. 11878. Convention date, April 27, 1935. [Class 38 (v)] A rotary switch for converting high-tension three-phase currents of heavy current values comprises a container 401, three A.C. lead-in insulators 402 .. 404 projecting into the container, each insulator carrying at its inner end' an even number of contacts 408 .. 413 arranged to form two groups consisting of one or more sets of three contacts with the three contacts of each set symmetrically disposed around the periphery of a circle, and two D.C. electrodes 414, 415 rotatably mounted within the container so as to co-operate respectively with the two groups of A.C. contacts, the D.C. electrodes being rotated at 1/p times the synchronous speed and each D.C. electrode comprising p symmetrically arranged arcuate contacts of equal length together extending over an arc of 120 geometrical degrees. The arrangement is such that an arcuate contact of one D.C. electrode engages each A.C. contact of one group 180 electrical degrees after the corresponding arcuate contact of the other D.C. electrode engages the corresponding A.C. contact of the other group. In the arrangement shown p=2, each D.C. electrode comprising a pair of arcuate contacts each extending over 60 geometrical degrees, the electrodes being rotated at half the synchronous speed by motors 417, 419 connected through transformers 422, 423 to the three-phase mains. The current connection to the D.C. electrodes is made by leads extending through insulators 420, 421 on the outer ends of which the motors are mounted. The container may be filled with an arc quenching medium. In a modification, Fig. 4 (not shown), the rotating electrodes are driven from the motors through insulating spindles, and the connections are made through separate lead-in insulators and sliding-contacts ; in this construction the insulators may serve as outlets for a flowing quenching medium. In another modification, one of the A.C. electrodes is arranged vertically below the axis of rotation of the D.C. electrodes, and is mounted on a current bridge which is parallel to the axis of rotation.