Patent GB-384528-A (GB)
Title: Improvements in switch gear for electric transformers
IPC: H01H9/00
Filed: 1932-04-13
Abstract: 384,528. Regulating transformers. JANSEN, B., 7, Brunnleite, Regensburg, Germany. April 13, 1932, No. 10601. [Class 38 (ii).] In switch gear for voltage regulation for electric transformers having tap terminals, the two separately movable members of a selector switch are connected alternately with the line by a snap action switch, the tap terminals being so disposed that when the selector member connected to the line is in contact with one of these, the other selector member can be moved to pre-select the next higher or lower tap terminal. In the form shown in Fig. 1, the line A is connected alternately to. the vertically movable selector members E, F by the leads B, C and the double contact snap action switch controlled by a spring connection K to a point L on a crank arm on the upper end of the vertical control shaft H. The lower end of the shaft H carries a drum J of insulating material having a groove which engages rollers g on the selector members E, F, the spacing for the rollers being equal to the spacing of the tap terminals 0 .. 6. The groove has two helical portions joined by a semicircular portion so that rotation of the drum through half a revolution moves one of the selector members into contact with the next tap, the other member remaining stationary. The selector member so operated is thus connected to the line by the snap action switch, the other selector member being disconnected. In the position of adjustment shown, the secondary circuit includes the transformer winding 0 .. 1, the selector member E and the line A. Rotation of the shaft H through half a revolution moves the selector member F into contact with tap terminal 2 and operates the snap action switch so that the secondary circuit then includes the transformer windings 0-1, 1-2, and the selector member F. Further rotation of the shaft H brings the other transformer windings into the circuit in succession. In the modification shown in Fig. 2, the line voltage is raised or lowered to an adjustable extent by a secondary coil the connection to which may be reversed. When the selector member F makes contact with tap terminal D, the feeder N and the main A are directly connected ; but when the selector members are above this central position, the voltage in the secondary main A is stepped up by connecting the feeder to the main A through one or more of the windings 0 .. 6. When the selector members are below the central position the windings are in opposition. The tap terminals 0, 6 are connected alternately to the main N, according to whether the selector members are below or above the central position D, the change over being effected by a conductor M having a sliding connection tap D and movable up or down, to make contact with tap 0 or tap 6. The movement is effected by a lever which engages a slot R<1> in the selector member E when this member moves between the tap terminals 1, 5. In the further modification designed for a three-phase system, Figs. 3 and 5, the two series of tap terminals 0, 2, 4, 6, 8 and 1, 3, 5, 7 are disposed in semicircles and are engaged by contact arms P, Q which are rotated alternately one step at a time by rotation of the central shaft H through the toothed gearing shown in Fig. 6. The three-phase connections I, II, III are arranged one above the other and operated simultaneously. The three contact arms P, Q arranged on each side one above the other are connected by rings and leads passing through 'the block of insulated material between the shaft H and the tubular casing up to the threepole snap action switch which is operated by an electric motor supplied with current from the circuit through leads also passing up through the insulated central block.