Patent GB-190804852-A (GB)
Title: Improvements in Alternating Current Commutator Dynamo Electric Machines.
Inventor: DOINIKOFF WLADIMIR
Filed: 1908-03-03
Granted: 1909-06-03
Abstract: 4852. Doinikoff, W. March 3. Dynamos, alternating-current; motors, alternating- currecet ; rotary converters ; sparking, preventing.- To prevent sparking at the brushes of single-phase and polyphase commutator machines, the wires connecting the armature windings with the commutator are wound on one or more auxiliary armature iron cores where they are acted upon by commutating field poles, and the windings of the commutating-poles are each connected between two points of the main armature winding, the line connecting which is substantially at right-angles to a diameter through the point of connexion of the corresponding brush. As applied to a three-phase-to continuouscurrent converter, Figs. 5 and 9, the armature winding A of which is connected both to slip rings and to a commutator C, the commutator connexions are wound upon an auxiliary armature core Ah, and each commutating-pole is split up into two parts p<1>, p<11>, the commutating-pole windings p<1>2, p<11>2, for example, being connected across the brushes B1, B3, and so on. Each commutating-pole section may have a separate yoke, as shown in Fig. 9 ; or all the sections P<1> may form part of one circular yoke, Fig. 26, the sections p<11> forming part of a second yoke ; or more than two yokes may be provided. To enable the angle between the brush diameter and the line joining the armature commutating connexions to be adjusted, an auto-transformer T, Fig. 10, having a drum or ring core and a closedcircuit winding may be inserted between the brushes and the commutating-windings. The three brushes B1, B2, B3 are connected in parallel with this winding at symmetricallydistributed points b<1>, b<2>, b<3>, and the commutating-windings are connected to adjustable points thereon as shown. The invention is also described with reference to single-phase compensated repulsion motors of the Winter-Eichberg, Latour, and similar types, the primary connexions on the auto-transformer being made to correspond to the connexions and disposition of the brushes upon the commutators. Some of the equipotential points on the auto-transformer may be connected together. Fig. 21 illustrates an arrangement in which the commutating-windings are all connected in series across the exciting- circuit of the motor. The number of ampereturns for each section of a single commutating-pole may be either equal or different. The commutating-windings may be arranged on any desired part of the commutating-pole magnetic circuit ; for example, they may be wound uniformly round the stationary circular yokes, or upon the rotating auxiliary armature core, Figs. 26 and 27, which is then split up into two rings A<1>h and A<11>h arranged side by side, exciting-windings EW<1>, EW<11>, either simplex or multiplex, for the commmating-poles being placed on both rings. The main armature winding A has three branching points a1, a2, a3 connected to the commutating-pole windings, the point a1, for example, being adjustably connected to the points e1, e<11>1 of the exciting-windings respectively displaced with reference to the point a1 by approximately 90 degrees. The commutator connexions are formed as an open-coil drum winding wound on both auxiliary armatures. A frequency converter having four auxiliary armatures is also described. The air-gap in the commutating-poles may be omitted and the two sections brought together ; the commutating-pole may be distributed over the auxiliary armatures. Fig. 30 shows a single-phase-to continuous current converter having the main armature winding A connected to the alternating-current terminals S1, S2 and to a commutator C. The commutating-coils p<1>1, p<11>1 . . . are connected to points a<1>1, a<11>1 . . . on a closedcircuit auxiliary stator winding HW. Three or more brushes may be used on the commutator, and the commutating-poles may have more than one winding. In rotary-field frequency converters and in the converter shown in Fig. 30, the points on the armature winding connected to the commutating-windings may be situated in the diameter drawn through the corresponding brush, instead of being-at right-angles thereto.