GB369646A - Electrical adjustable resistance - Google Patents

Abstract

369,646. Wire variable and selfsupporting resistances. ULITOWSKY, A., 1, Moshkow per, Leningrad. Nov. 17, 1930, No. 34614. [Class 37.] In a variable electric resistance suitable also for heating purposes, in order to provide improved heat dissipation strips of conducting material 2, forming the main resistance, are laid parallel to the axis on a cylindrical ceramic former 1 and a layer of comparatively high resistance wire 3 is wound helically on the strips, individual turns of the wire being insulated by an oxide coating but being in conductive contact with the underlying strips. Alternatively, the strips may be replaced by a sheet of metal or a layer of conducting material 9a, Fig. 5, or the overlying winding may be formed by winding two wires 3, 3a together, one of which, 3a, is bare and the other oxide-coated all over. In a modification the central core is dispensed with and the conducting strips are radially mounted between insulating end-pieces so as to form a polygonal frame on which the overlying layer is wound as before or in the form of a basket-like braid, clearance being allowed between turns. Connection is made from the supply to the underlying strips which may be of thin platinum wire or material known under the registered Trade Mark " Nichrome " in a modification used as a furnace heating element. When used as a variable resistance a slider mounted on a bar in the usual way bears on the surface of the layer 3 and makes contact through it or through the base wire 3a, with the main resistance strips. The layer 3 may consist of strip material wound on edge. Terminals mounted on the end supports of the resistor make connection to the slider bar and through end rings 4<1> with the underlying resistance strips.