GB411769A - Improvements in or relating to electric regulating transformers for continuous voltage regulation - Google Patents

Abstract

411,769. Regulating transformers. AKT.-GES. BROWN, BOVERI, ET CIE, Baden, Switzerland. Dec. 18, 1933, Nos. 35629, 35630, 35631, and 35632. Convention dates, Dec. 17, 1932, March 23, 1933, May 24, 1933, and Nov. 8, 1933. [Class 38 (ii).] A transformer is arranged for continuous regulation by means of the provision of discshaped spirally wound coils of bare conductor arranged in pairs in parallel planes, a single current collector for each pair of coils being arranged between them, the collector having two contacts each one contact engaging the conductor of one of the pair of coils. Thus, as shown in Fig. 1, the spirally wound disc-shaped coils b are mounted on an insulating tube f surrounding the primary winding h and the core i. The turns of the coils a formed of copper strips b are separated by an insulating strip c which is wider than the coil itself so that between them spring contact plungers e may be pressed by a spring d into contact with the edges of the coils. The tube f is rotatable about its axis so that the contacts d move along the complete length of the coils to vary the output voltage, the current collected being held by a conductor g which is guided radially. Alternatively, the secondary coils may be stationary and the current collector movable around the axis, arrangements to permit its radial movement being provided, for example, as by carrying the contacts on an arm pivoted to the end of the rotatable collector (Figs. 9 and 10, not shown). Several pairs of coils, each with a current collector between them, may be provided and these pairs of coils may be placed in series or in parallel circuit. The contacts e themselves may be in series or in parallel and may be insulated from each other. The conductors passing to the contacts in each case are so arranged that currents flowing to them reinforce the contact pressure electrodynamically. Various forms of core may be employed, and different forms of shell-type cores are described either of involute form or of a series of radially projecting core sections to produce uniform flux distribution in the secondary windings. Alternatively, each pair of secondary coils may be associated with a separate core, the operating and conducting members of the current collectors g (Fig. 8) passing through air gaps in t in the core sections q, these air gaps as shown being inclined to minimize leakage. The primary winding sections may be interlinked between the turns of the secondary coils as shown in Fig. 11 in which sections h are embedded in the insulating material c between the turns of the secondary winding which project inwardly, the current collector having contacts in the form of the flanged rollers e.