GB190321208A - Improvements in Alternate Current Meters. - Google Patents

Abstract

21,208. Compagnie pour la Fabrication des Comptours et Materiel d'Usines a Gaz. Dec. 16, A.D. 1902, [date applied for under Patents Act, A.D. 1901]. Energy meters.-An induction motor meter for a single alternating current has a conductive disc or cylinder A, Fig. 2, revolving in the field of two electromagnets, one of which fE has windings nE in a highly inductive circuit between the supply mains ; the other electromagnet f<3> has a nearly closed magnetic circuit, independently of the rotor A, and a highly inductive winding ni carrying a shunted part of the main current, so that its magneto-motive force reduces that of the principal main-current winding nI, which is less inductive and is placed on a straight extension of the electromagnet f<3>, in the form shown in Fig. 2. The magnetic flux thus produced by the co-action of the two main current coils n1, ni is in quadrature with the flux produced by the pressure windings nE when the load is non-inductive. This result is obtained by adjusting a slider on resistances r in series with the main-current winding nI, these parts collectively being connected in parallel with the subsidiary main-current winding ni. Otherwise the principal winding nI may carry the whole maincurrent, and the subsidiary winding ni be placed in parallel with a less inductive shunt resistance. The revolution of the rotor A is retarded by a permanent magnet. One electromagnet may be displaced angularly or laterally relatively to the other, to compensate for friction at low speeds, and increased braking effect and "saturation" of the iron at high speeds. In the modification shown in Fig. 6, the electromagnet fE carrying the pressure windings nE has a nearly closed magnetic circuit, independently of the rotor A, and has straight extensions to carry the principal maincurrent winding nI near the edge of the disc A. In a further modification, this winding is a coil placed beside the poles of the electromagnet fE. In the actual construction of the meter, the magnets and spindle bearings are secured on the surfaces of a slotted vertical plate, which is supported by pillars on the back of the meter.