GB415999A - Improvements in and relating to speed regulating devices for electric motors - Google Patents

Abstract

415,999. Motors ; transformers. INTERNATIONAL GENERAL ELECTRIC CO., Inc., 120, Broadway, New York, U.S.A.- (Assignees of Allgemeine Elektricitõts-Ges.; 2, Friedrich Karl-Ufer, Berlin.) Dec. 2, 1932, No. 34190. Void [Abridged as open to inspection under Sect. 91 of the Acts, June 4, 1933]. [Classes 35 and 38 (ii).] Machines with vapour or like rectifiers in place of commutators.-In a commutatorless motor fed by one or more transformers, some of the transformer windings are directly associated with the grid controlled vessels by which the commutation is effected. A plurality of transformer secondary windings is employed, either on separate cores or on a common core. In the form shown in Fig. 2 the transformer secondary windings 4, 6, 8 have a centre tapping connected to the field winding 31. The stationary armature 32 has six windings of which three conduct current simultaneously ; thus, after the commutation of the current from 25 to 24 has been effected the windings 24, 26 and 28 are effective until the next winding, for example 26, approaches its neutral position and the current is commutated from 26 to 27. In an alternative form, the single anode tubes are replaced by a single multiple anode discharge vessel and there are two secondary windings on each transformer with their ends connected to the anodes and their centre tappings connected to the ends of the windings, the field winding in this case being connected between the cathode and the neutral point of the armature. In the form shown in Fig. 3, the valves are connected in parallel in opposite senses and the current flows continuously in the windings. Thus, when group 13, 14 is made conductive, the current through winding 24 which had been flowing through 11 (or 12) immediately reverses and flows through 14 (or 13), a negative grid potential having been applied to 11, 12. In this arrangement, the rotary field winding 31 is fed with alternating instead of rectified current from the supply directly or through a current transformer 33. Instead of three separate transformers 10, a single five limbed one may be used with the primary and secondary windings on the three central or on the centre and outer limbs, the three primary windings, one per wound limb, being in series.