TEMPERATURE COMPENSATED MAGNETIC DAMPING ASSEMBLY FOR INDUCTION METERS

摘要

A temperature compensated magnetic damping assembly for providing a braking torque on an electroconductive disk of an induction device is disclosed. A pair of permanent magnets each has an easy axis of magnetization. Each permanent magnet provides two easy flux paths parallel to the easy axis of magnetization and separated by a dead zone. The permanent magnets are juxtaposed about a predetermined space through which the disk rotates such that the easy flux paths are perpendicular to the disk. The permanent magnets are aligned such that the magnetic flux passes twice through the disk in opposite directions. Flux return plates are provided adjacent to each of the permanent magnets so as to provide a flux path parallel to the disk and linking the two easy flux paths of each of the permanent magnets. In this configuration, a highly-efficient, substantially square magnetic flux loop is provided. One of the flux return plates is movable relative to the adjacent permanent magnet so as to provide series adjustment of the damping torque. Finally, a temperature sensitive magnetic shunting member extends from the north to the south pole, across the dead zone, of each of the permanent magnets so as to provide temperature compensation.