GB642326A - Magnetic control system - Google Patents

Abstract

642,326. Transformers and inductances; control systems for arc-welding; dynamoelectric machines. NATIONAL CYLINDER GAS CO. Aug. 13, 1947, No. 22538. Convention date, Aug. 17, 1946. [Classes 35, 38 (ii) and 38 (iv)] [Also in Group XXXVII] In a magnetic control system a control device for effecting varying pre-determined relations between juxtaposed surfaces comprises a pair of relatively rotatable members of which the juxtaposed surfaces are involutes of a common evolute so that upon relative rotation of the members the surfaces are at a uniform distance from each other depending upon the degree of rotation. A welding transformer 12 has a preferably laminated coremember 13 comprising legs 14, 15 carrying fixed primary and secondary windings 11, 18 and a third leg comprising polar projections 24, 25 and a rotatable member 29. The surfaces 26, 27 and 30, 31 are all involutes of an evoluted base cylinder 32 and the co-operating surfaces, i.e. 26, 30 or 27, 31, are parallel for any position of the member 29 if the axis of the member and the axis of the base cylinder are co-incident. The air-gaps are thus always of uniform length over the co-operating surfaces, but are adjustable by movement of the member 29, thus ensuring uniform flux distribution in the airgaps. Adjustment of the air gap varies the flux carried by the shunt path thus varying the flux linking the secondary winding and consequently the current in the weld. By the omission of the secondary winding and the core leg 15 a variable inductance may be constructed. In other embodiments are described transformers, which may have movable secondary windings. In still further embodiments are described dynamo-electric machines having a field shunt, which is similar to the shunt in Fig. 2, in order to vary the flux passing through the armature or alternatively the flux varying member may take the form shown in Fig. 8. In this Figure the surfaces C-D of the pole 103 and A-B of the member 123 are involutes of a common base cylinder 117. A similar arrangement exists for pole 104. Movement of the members 123, 124 varies the air gaps and hence the flux passing through the armature. The members 125, 126 may be either fixed or movable but movement thereof does not vary the air-gaps either between them and the armature or between them and the members 123, 124. Alternatively they may be dispensed with (Fig. 7, not shown). Specifications 480,295 and 586,503 are referred to. The Specification as open to inspection under Sect. 91 comprises also an electromagnet, Fig. 9 (Cancelled), in which the movable core member or rotor co-operates with core legs at right angles to each other, the rotor surface being either a single involute or a combination of an involute and a circular arc, the fixed surface being correspondingly shaped. This subject-matter does not appear in the Specification as accepted.