GB408935A - Improvements relating to motors for electric meters - Google Patents

Abstract

408,935. Supply meters; power meters. MARTIN, A. J., 5, Milton Crescent, Ilford, Essex. Oct. 13, 1932, No. 28603. [Class 37.] In an induction disc driving motor for indicating and integrating watt meters having the potential core 1 mounted between two current cores 10, the line joining the centres of the polepieces of these cores being perpendicular to a radius of the disc 21, a limb 2 of the potential core is closely adjacent to one face of the disc leaving room for the current winding or windings on a part of the current cores more remote from the disc and a limb 11 of each of the current cores is closely adjacent the other face of the disc 21 leaving room for the potential winding on a part of the potential core more remote from this other face of the disc. The cores are formed with enlarged pole -pieces adjacent the disc and are bolted together by non-magnetic bolts 18, distance pieces 20 separating the adjacent faces of the cores. The poles of the current cores are provided with overload bridges 22 and a similar overload bridge 23 consisting of a strip of magnetic material is provided for the potential magnet. To ensure a good contact of large area the ends of the strip 23 are bent round the ends of a non-magnetic strip 24 which wedges them into depressions formed in the limb 4 and pole-piece 8 respectively. Other forms of bridge and modified core shapes may, however, be employed, Figs. 3 and 4 (not shown). Instead of each current core carrying a separate winding a common winding embracing both cores may be employed. Plates of non-magnetic but high conductivity material may be placed between the cores and outside the assembly for the purpose of concentrating the fluxes by reason of the induced eddy currents where such concentration is desired.