Magnetic damping assembly with temperature compensator for watthour meters
AssigneeWestinghouse Electric Corp.
InventorsJohn A. MacFadden, James E. Ramsey
Life of this patent
Estimating the term…
Abstract
A watthour meter damping assembly includes a U-shaped magnetic yoke and a pair of highly coercive and anisotropic permanent magnets projecting in facing relationship from the ends of the yoke. Opposing pole faces of the magnets form an air gap receiving a meter disc to be magnetically retarded. A single temperature compensator extends over the pole faces of the permanent magnets to form a compensating shunt flux path around the air gap. The compensator and magnetic yoke extend substantially parallel to each other from the inner and outer pole faces, respectively, of the magnet pair.
Claims17
A magnetic damping asembly for watthour meters having a rotatable electroconductive disc, comprising:
- a U-shaped magnetic yoke member having oppositely disposed legs extending over opposite sides of the path of rotation of the meter disc;
- a pair of permanent magnets extending from the inner sides of said yoke member so that opposing pole faces thereof have a predetermined spaced relationship for receiving the disc and directing a braking magnetic flux into the disc;
- and
- a temperature compensator means extending over said pole faces of said permanent magnets and forming a continuous shunt flux path therebetween so that divided portions of magnetic flux from said pole faces are directed either through said hunt flux path or through the space between said pole faces.
A magnetic damping assembly for watthour meters including a frame supporting a rotatable electroconductive disc and a housing carried by said frame for receiving said magnetic damping assembly in a predetermined position over opposite sides of said electroconductive disc, said magnetic damping assembly comprising:
- a U-shaped magnetic yoke member made of a soft magnetic material and having extending leg portions having flat inner sides extending in facing relationship on opposite sides of said disc when said magnetic yoke is carried within said housing;
- a pair of permanent magnets extending from said flat inner sides of said yoke leg portions and terminating at flat pole faces having a predetermined facing and spaced apart relationship for receiving the opposite sides of the electroconductive disc;
- a U-shaped temperature compensator member made of a strip of magnetic material having a negative temperature coefficient of permeability, opposite leg portions of said temperature compensator member extending over said pole faces of said pair of permanent magnets so as to concurrently form a temperature responsive shunt flux path and a support against the pole faces for holding said temperature compensator member in place and for further holding said pair of permanent magnets against said inner sides of said yoke member;
- and
- a full-load soft magnetic adjusting member disposed adjacent said yoke member and movably mounted in said housing so as to vary magnetic flux in a primary flux return path between said permanent magnets and through said yoke member.
Dependencies are inferred from the claim text.