GB190813092A - Improvements in and relating to Electric Transformers. - Google Patents

Abstract

13,092. Akt.-Ges. Brown, Boveri, et Cie. June 28, 1907, [date applied for under Section 91 of Patents &c. Act, 1907]. Rotary transformers; field magnets.-A directcurrent transformer of the type referred to iu Specification No. 9146, A.D. 1908, in which are utilized two magnetic fields at right-angles to one another, is constructed with two independent direct - current armatures with independent or common field systems. The arrangement of the two machines is such that the flux produced by the armature of the one machine, or of the armature and part of the winding of the field system in series therewith, or by the latter only, always enters the other rotor perpendicularly to the excitation axis of this rotor. In Fig. 1 the two machines a, b are shown with independent field-magnet systems. In the modification shown in Figs. 2 and 3, the field system of the transformer is composed of four pole-pieces p<1>, p<1>, p<2>, p<2> magnetically insulated from each other and without exciting-windings. The brushes b', b<2> of the primary and secondary circuits respectively are arranged at right-angles to each other so that the magnetization produced by the two circuits follows the paths f<1>, f<2> respectively. In a further modification, the poles p<1>, p<1>, p<2>, p<2>, Fig. 3, are divided and connected together in pairs, giving the arrangement shown in Fig. 4, in which the flux produced by the circuit I follows the path f<1>. The characteristic of the transformer may be varied by altering the number of windings, the air gaps, the position of the brushes, or by means of resistances. The system may be rotated by disturbing the equilibrium of the torque of the two halves of the machine. Auxiliary poles may be provided to improve commutation.