GB360418A - A device for reducing armature reaction in dynamo electric machines of the homopolar type - Google Patents

Abstract

360,418. Dynamo-electric machines. PLATEN, B. C. VON, 6, Lilla Baltgatan, Stockholm. May 5, 1930, No. 13757. Convention date, May 3, 1929. [Class 35.] Polepieces, armatures and field magnets, dampers on cores of; inductor machines; machines with two or more armatures; rotary transformers.-In a homopolar machine of the type described in Specifications 323,498 and 323,549, [both in Class 35, Dynamoelectric generators &c.], a rotary flux distributer is located axially intermediate the rotor poles adapted in conjunction with the rotor poles to reduce armature reaction. The arrangement is such as to cause damping or interruption of the armature reaction flux in all positions of the rotor. The invention is described in connection with a continuous current transformer having primary and secondary windings 9, 9<1> on stationary cores 1 .. 4 connected respectively to commutators C, C<1>. The laminated rotor poles N, S held between clamping plates which may be of copper are angularly displaced by 45‹ on the shaft 30 which carries the stationary or rotating exciting windings 7, 8. The casing 25 is of nonmagnetic material and the cores 1 .. 4 are surrounded by aluminium covers 28 which serve as damping devices. The field distributer F comprises two annular magnetic segments 31, 32, Fig. 4, separated by nonmagnetic segments 33 which extend over the overlapping surfaces of the poles N, S viewed in the axial direction. The air gap between the poles N, S and the stator cores is equal to the air gap between the stator and the flux distributer F except at the parts of the poles corresponding to the spaces 33 where the gap is twice as long. Diagrams are given showing the paths of the useful flux and also showing that the armature reaction flux when allowed to form a closed circuit, closes at one end of the rotor. Preferably the parts of the poles near the air gap only are laminated so that the armature reaction flux must pass partly through nonlaminated iron in which damping currents are set up. In order to reduce armature reaction still further, a damping coil may be provided around the path of the armature reaction through the poles, for example, the copper clamping plates of the poles may be connected by copper bolts. In the case of a generator, continuous or alternating current may be produced.