GB879793A - Constant-potential compounded a.c. generators - Google Patents

Abstract

879,793. A.C. generators. TARDEL, K. Nov. 28, 1957, No. 37170/57. Class 35. In a constant-potential A.C. generator such as disclosed in Specification 706,233 and comprising an exciter armature 10 carrying both an excitation winding 13 whose end wires extend through the generator armature 11 whereby a no-load component of excitation current can be induced in such end wires by the main field, not shown, of the generator, and an auxiliary winding 12 connected to be energized by the generator load current and arranged to induce a load component of excitation current in the excitation winding 13, a non- rotating annular magnetic member 14 surrounds the exciter armature 10 and is spaced therefrom by an air gap 15 whose dimensions are variable by mechanical adjustment of the member to alter the reluctance of the magnetic circuit and hence the compounding characteristics of the generator. This alteration is to compensate for a drop in speed of the driving machine or to enable the generator to run in parallel with other generators, and as shown in Fig. 1 is achieved by moving the member 14 axially. In other embodiments the member has a single split 30, the width of which may be adjusted by various mechanisms such as the cam 31, 32 in Fig. 3, or the member may comprise two halves relatively radially movable by a mechanism such as the screw 45 ... 47 in Fig. 6.