US 4,220,934 AGranted

Current limiting circuit breaker with integral magnetic drive device housing and contact arm stop

AssigneeWestinghouse Electric Corp.

InventorsJohn A. Wafer, Robert H. Hill, William I. Stephenson, Jr.

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Abstract

A current limiting circuit interrupter comprises a molded case, separable contacts disposed in the case, the contact arms supporting one of the contacts, an operating mechanism connected to the contact arm to move the arm between open and closed positions, and a slotted magnetic drive device generating electrodynamic force on the contact arm during extreme overcurrent conditions to rapidly separate the contacts. The magnetic drive device includes a molded housing forming a slot having insulated walls disposed about the contact arm, and a stack of U-shaped laminations of magnetic material fitted into the housing. The space between opposing walls of the housing is slightly less than the thickness of the lamination stack so that the laminations may be snugly press-fitted into the housing. The housing is then secured to the case in such a manner that the laminations are captured and securely positioned without the need for rivets or other fastening means extending through the lamination stack. The housing also includes molded recesses for receiving a compression spring to produce contact force when the contacts are in the closed position, and a molded stop member to limit the movement of the contact arm when the breaker is in the open position.

Claims6

Dependent claims

Current limiting circuit interrupter apparatus, comprising:

a case;
separable contacts disposed in said case;
a movable contact arm supporting one of said contacts;
an operating mechanism connected to said movable contact arm for operating said movable contact arm between open and closed positions during conditions of normal current flow through said apparatus;
and
a slotted magnetic drive device for generating electrodynamic opening force on said movable contact arm, comprising an insulating housing and a stack of U-shaped laminations of magnetic material each having a pair of legs connected by a bight portion;
said housing comprising a pair of spaced parallel insulating side walls parallel to the plane of movement of said contact arm and disposed on either side thereof, and a plurality of resilient retaining walls parallel to said laminations perpendicular to said side walls and outwardly extending at each end therefrom, the distance between said retaining walls being slightly less than the thickness of said lamination stack;
said lamination stack being press fitted into said housing between said retaining walls and positioned with respect to said housing such that said laminations are parallel to the retaining walls, said side walls are between the legs of each of said laminations, and said retaining walls are flexed to produce a force compressing said lamination stick.

5 more elements

Dependencies are inferred from the claim text.