GB343052A - Improvements relating to dynamo electric generating machinery particularly applicable for use in electric arc welding - Google Patents

Abstract

343,052. Dynamo-electric machines. QUASI-ARC CO., Ltd. and MUSTO, R. J., 15, Grosvenor Gardens, London. Nov. 6, 1929,.No. 33801. [Class 35.] Yokes and carcases ; exciting.-A continuouscurrent generator for electric arc welding purposes is arranged to have a drooping characteristic by placing slightly in front of each main pole, in the direction of rotation of the armature, an auxiliary pole which carries a series winding acting in opposition to the main shunt winding carried by the main poles. To ensure a substantially constant shunt field the winding T carried by the main poles A<1>, B<1>, A<2>, B<2>, is excited from two auxiliary brushes l, k one of which is placed to connect with conductors situated between a main pole B<2> and its auxiliary pole C<2> and the other to connect with conductors slightly on the leading side of the central plane of the pole B<2> so that they embrace a nearly constant flux. One auxiliary brush b only need be used when the second connection is made with a main brush. A compounding series winding r is provided on the main poles. To control the load current when electrodes of different gauges are used the series winding on the auxiliary poles a<1>, b<1>, a<2>, b<2> is tapped in sections s<1>, s<2>, s<3>, s<4>, and a switch f used to control the number of sections in circuit. Alternatively a variable inductive diverter is placed across the series winding. The yoke Y, Fig. 3, is made of small cross section and plates x, y of small cross section are used to connect the polepieces to the yoke so that the magnetic circuit of the machine is saturated at low armature voltages.