Siemens Energy & Automation, Inc.

Neal B Reeves

Bernard DiMarco

Bruce D Guiney

David A Leone

James Edward Ferree

Robert E Black

Mark Blankemeyer

A circuit breaker ( ) including a stationary line bus assembly ( ). The stationary line bus assembly ( )comprises a bus body ( ) supported by support legs ( ) with the bus body ( ) having a first longitudinal end portion ( ) and a second longitudinal end portion ( ), with each end portion terminating at a common end portion ( ). The second end portion ( ) includes a stationary contact bus ( ) in a spaced relationship from the first end portion ( ). A line terminal ( ) is mounted on the first longitudinal end portion ( ) and a contact ( ) is attached to the second longitudinal end portion ( ). In one embodiment, a bus support ( ) is attached to the bus body ( ) in the space between the first end portion ( ) and the second end portion ( ) and separated from the support legs ( ) of the bus body ( ) by an insulating barrier ( ). The stationary bus support ( ) can have several configuration.

Stationary line bus assembly

A circuit breaker (,) including an electrical arc extinguishing apparatus (,). The electric arc extinguishing arc apparatus (,) includes a first sidewall (,) in a spaced relationship with the second sidewall (,) with a top arc plate (,) mounted between the first and second sidewalls (,). A plurality of intermediate arc plates (,) are mounted between the first (,) and second sidewalls (,) below the top arc plate (,) with each in a spaced apart relationship. A bottom arc plate (,) is mounted between the first and second sidewalls below and apart from the intermediate plates (,) forming an arc chute. The electric arc extinguishing apparatus (,) can also be provided with two end caps (,) with each end cap (,) having an interior cavity (,) with one leg (,) of each arc plate (,) mounted in the cavity (,) of one end cap (,) and the other leg (,) of each arc plate (,) mounted in the cavity (,) of the other end cap (,).

ARC chute for a molded case circuit breaker

A circuit breaker housing includes a base having a main portion and a separate subbase portion. The line contact arms for the breaker are mounted on the subbase portion and attached to the main portion which includes the load contact arms. The main portion of the base includes a bottom wall which insulates the load contact arms from the line contact arms along a portion of their lengths. In addition, the bottom wall forms a structural member which rigidly ties the two sidewalls of the main portion of the base. The bottom wall of the main portion of the base includes an opening through which line contacts coupled to the line contact arm make contact with load arm contacts coupled to the load contact arms. Adjacent to the opening, the main portion of the base includes vertical ribs directly tied to the bottom wall which strengthen internal and external side walls in the main portion of the base and reinforce the structural member formed by the bottom wall of the main portion of the base. The subbase may be attached to the base with screws, adhesives, a combination of screws and adhesives or by other methods.

Multi-part circuit breaker housing

A circuit breaker includes a cam assembly which holds the load blade in contact with the line strap during normal operation. The cam assembly includes a cam surface on a cam which can slide along the load blade and a bearing surface on the load blade. In normal operation, the cam is biased on the load blade so that the cam surface engages the bearing surface. The force applied by the cam surface to the bearing surface in normal operation is approximately parallel to the force applied by the load blade to the line strap, thus, the cam surface does not tend to slide along the bearing surface during normal operation. When a high overcurrent fault occurs, blow-open forces exerted between the load blade and the line strap cause the cam to pivot to a position where the cam surface no longer engages the bearing surface, allowing the load blade to swing free of the cam and break the contact between the load blade and the line strap. As the load blade swings free of the cam, it engages a further cam surface of the cam which reduces the biasing force essentially to zero, thereby increasing the opening speed of the blade. In addition, the frictional force of the further cam surface against the load blade prevents the load blade from reestablishing contact with the line strap until the mechanism trips, keeping the load blade in the open position.

Circuit breaker having a cam structure which aids blow open operation

A molded case circuit breaker includes a generally 'Z' shaped intermediate latch structure which has upper and lower substantially planar sections that are each bent at an angle with respect to a center pivot section. The upper portion of the intermediate latch includes one or two latch surfaces. One of these latch surfaces engages the cradle of the operating mechanism of the circuit breaker, to latch the operating mechanism when the circuit breaker is closed. The other latch surface engages a trip bar or an intermediate latch bar, which is rotated by the trip unit when an overcurrent condition occurs. The lower portion of the intermediate latch structure also includes a latch surface which may engage a trip bar. This latch surface is sloped such that when the latch surface of the trip bar is moved along this sloped latch surface, the trip bar rotates. This rotation of the trip bar adjusts the spacing between the trip bar and a bimetallic strip or magnetic armature of a thermal and magnetic trip unit to allow the rating of the circuit breaker to be changed in the field. The pivot portion of the intermediate latch structure includes two mounting tabs, one on either side of the latch. The mounting tabs have a generally rectangular cross-section and, due to the angled relationship between the pivot portion and the upper and lower portions of the intermediate latch, the latch pivots on an edge of the mounting tabs. This edge is aligned with an angular opening in the mechanical frame to mount the intermediate latch. The mounting tabs also retain a biasing spring which biases the intermediate latch toward the cradle and biases the trip bar or latch bar toward the intermediate latch.

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Atlanta, GA, United States of America

Neal B Reeves