Abstract: A power circuit interrupter includes a housing having an opening, one or more vacuum interrupters including separable contacts, and an operating mechanism, supported by the housing, adapted to open and close the contacts. A linear actuator cooperates with the operating mechanism to open and close the contacts, and is responsive to a close signal to close the contacts. A pivotable trip member protrudes through the opening of the housing and cooperates with the operating mechanism and the linear actuator to open the contacts when pivoted from a first position to a second position. A close circuit includes an input inputting the close signal. A micro-switch includes an operator and a contact electrically connected in series with the input of the close circuit. The operator is engaged by the pivotable trip member to open the contact in response to partial pivoting thereof from the first position toward the second position.

Abstract: A flexible shunt in the form of a flexible member made up of a stack of electrically conductive laminations each of a thickness of no more than about 0.002 inch (0.051 mm) has a moveable end secured by a moveable mount to a moveable contact support of an electric power switch for movement along a linear path. A fixed mount secures the fixed end of the flexible member to a fixed conductor termination spaced laterally from the moveable end along a neutral axis perpendicular to the linear path of the moveable end by an offset distance such that the installed length of the intermediate section between the fixed and moveable ends is less than the free length of the intermediate section. With this arrangement the stroke of the moveable end along the linear path can be up to at least ⅓ and even ½ of the free length of the intermediate section of the flexible member and with very low operating forces.

Abstract: Operation of a medium voltage spring powered circuit breaker having an operating mechanism is analyzed by a test unit. The test unit includes a potentiometer having an input and a rotary shaft. A voltage source energizes the input of the potentiometer. A rotary wheel engages a driven part, such as a spring crank or a closing cam, of the operating mechanism to adjust the rotary shaft of the potentiometer and produce a variable output voltage thereof. The potentiometer tracks angular movement of the driven part and the output voltage corresponds to the variable angular movement of the driven part. A processing unit or an oscilloscope monitors the output voltage with respect to time in order to monitor the angular movement of the driven part with respect to time.

Abstract: Switchgear with a closing spring release and an opening release accessible from a front face is further provided with top mounted closing and opening spring releases. In order to avoid interference with internal parts of the switchgear and to follow the movement of the trip mechanisms to which they are connected, these top mounted spring releases are flexible elongated members preferably in the form of flat stainless spring steel straps. The flat strap of the top mounted opening spring release has a slot engaging the opening trip lever and is sized so as not to engage the trip lever when the front accessible spring release is otherwise actuated. As the horizontal pivot axis of the closing spring trip lever moves transversely, the flat strap of the top mounted closing spring release is oriented to bend in the same direction while the lower end section is twisted 90.degree. to receive a coupling pin on the trip lever.

Abstract: A molded-case circuit breaker having an undervoltage release device housed therein is provided with a flexible molded double ended lever for resetting the undervoltage release device and a torsion spring braced upon the two arms of the lever so as to minimize the effects of stress and creep on the molded members when manually actuating repeatedly to reset the undervoltage release device against the biasing spring of the device.