Circuit breaker with improved delay
AssigneeAirpax Electronics Incorporated
InventorsGeorge S. Harper, Lyal N. Merriken
Life of this patent
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Abstract
Disclosed is a magnetic circuit breaker having improved delay characteristics and particularly improved pulse tolerance. The trip coil of the breaker is spaced from the magnetic pole piece of a delay tube by a non-conductive, non-magnetic gap and the delay core is elongated. An inertia wheel is mechanically coupled to the trip armature to further increase pulse tolerance so as to reduce nuisance tripping in the presence of high but very short term overcurrents. The circuit breaker provides a significantly improved motor protection characteristic.
Claims17
A circuit breaker comprising a pair of electrical contacts, a handle, a collapsible toggle coupling said handle to one of said contacts, a movable armature having a portion adapted to engage and trip said toggle, a frame, a hollow delay tube carried by said frame and having a magnetic pole piece at one end, a magnetic core movable in said delay tube, a trip coil surrounding a portion of said trip tube, said coil being spaced from the plane of the near end of said pole piece by a non-conductive, non-magnetic gap having a length of from about one-fifteenth to about one-sixth the overall interior length of said delay tube, and spring means in said delay tube normally biasing said core into a position away from said pole piece, said core when in said position extending from the end of said delay tube remote from said pole piece to a point short of a plane containing the electrical center of said trip coil.
A protection circuit comprising a source of electrical power, a motor, a circuit breaker connected in series between said source and motor, said circuit breaker comprising a pair of electrical contacts, a handle, a collapsible toggle coupling said handle to one of said contacts, a movable armature having a portion adapted to engage and trip said toggle, a frame, a hollow delay tube carried by said frame and having a magnetic pole piece at one end, a magnetic core movable in said delay tube, spring means in said tube normally biasing said core away from said pole piece, and a trip coil surrounding a portion of said trip tube, said coil being spaced from the plane of the near end of said pole piece by a non-conductive, non-magnetic gap having a length of from about one-fifteenth to about one-sixth the overall interior length of said delay tube.
Dependencies are inferred from the claim text.