GB190126377A - Improvements in Induction Electric Meters. - Google Patents

Abstract

26,377. Blßthy, O. T. Dec. 24. Energy meters.-An induction motor meter has two iron cores 1, 3, respectively U-shaped and E-shaped, on opposite sides of the revolving disc 6, with their outer poles facing one another. The U-shaped core 1 carries pressure coils, and the middle limb 5 of the E-shaped core carries a main-current coil; the magnetic circuit of the latter thus includes an air space such that its braking effect on the disc is small relatively to its driving-action. The air space may be lengthened by removing the polar enlargements shown on the cores, or by providing a gap between the central pole-piece and a shortened middle limb on the E-shaped core 3. The middle limb may be adjustable, for which purpose the plates forming it may slide vertically in spaces left between the laminations of the core 3, when they are not clamped together by a bolt. The disc is retarded by a separate permanent magnet. For polyphase current measurements, two of the arrangements described may act on different parts of the disc.