Abstract: A compartment of an arc resistant enclosure for an electrical component includes a plurality of wall structures defining an interior space for housing an electrical component. One of the wall structures has aperture structure for permitting pressure and gases to flow there-from and vent from the compartment. A stop structure is associated with the aperture structure. Flap structure is associated with the aperture structure and is movable from a closed position covering the aperture structure to an opened position extending outwardly of the compartment permitting pressure and gas to exit the compartment through the aperture structure. In the closed position, a portion of the flap structure engages the stop structure to prevent the flap structure from collapsing into the interior space of the compartment.

Abstract: A containment system for internal arc generated gasses includes a compartment having an aperture through a wall thereof. A bus compartment includes an opening through a wall thereof. Arc chamber is in communication with the aperture and the opening. A vent flap member closes the opening and is moveable to an open position to permit gasses to flow through the opening into the arc chamber. Flap structure is associated with the aperture and includes a plurality of interconnected flaps for moving generally simultaneously from an open position, permitting gasses to flow through the aperture into the arc chamber, to a closed position, closing the aperture to prevent gasses from flowing through the aperture. The flap structure includes actuating structure coupled with the interconnected flaps. The vent flap member, when moved to the open position thereof, engages the actuating structure to move the interconnected flaps to the closed position thereof.

Abstract: A bushing structure for switchgear includes first and second separate support structures each having surfaces defining at least one opening. The support structures are coupled together so that the openings define a passage through the bushing structure and so that a slot is defined between the first and second support structures, surrounding the passage. A bushing is disposed in the passage and has a body, a bus receiving member, and a compression structure. The bus receiving member has an opening there-through sized to receive a bus bar. When the first and second support structures are coupled together with the bushing in the passage, the compression structure is disposed in the slot, sandwiched between the first and second support structures so that they exert pressure on the compression structure.

Abstract: A compartment of an arc resistant enclosure for an electrical component includes a plurality of wall structures defining an interior space for housing an electrical component. One of the wall structures has aperture structure for permitting pressure and gases to flow there-from and vent from the compartment. A stop structure is associated with the aperture structure. Flap structure is associated with the aperture structure and is movable from a closed position covering the aperture structure to an opened position extending outwardly of the compartment permitting pressure and gas to exit the compartment through the aperture structure. In the closed position, a portion of the flap structure engages the stop structure to prevent the flap structure from collapsing into the interior space of the compartment.

Abstract: A truck (12?) for mounting a circuit breaker (13) in a switchgear frame (14?) includes wheels (16), a racking screw (20), a nut (22) threaded with the racking screw. The nut floats linearly with respect to the truck. A spring (23) is provided between a portion of the truck and the nut such that during movement of the truck into the frame, rotation of the racking screw causes linear movement of the nut, with the nut pushing against the spring, with the spring pushing the truck to move the truck linearly. Locking structure is coupled with the such that when the truck is stopped and the racking screw continues to rotate, the nut will move to compress the spring, causing the locking structure to move from an unlocked position, disengaged with the frame, to a locked position, engaged with the frame.

Abstract: A contact arm assembly (10) for a switchgear circuit breaker includes a contact arm (11) having a groove (42) in an outer periphery surface thereof. At least one contact finger (13) has a body (38) and a ball member (40) extending from the body. The ball member is received in the groove so that the contact finger makes contact with the contact arm. The contact arm includes a shaft (14) having a longitudinal axis, first and second ends (18, 28), and a constant outside diameter. A plurality of annular rings (16) extends from the outside diameter of the shaft. The rings are spaced along the longitudinal axis to define cooling fins. Diameters of the rings gradually decrease from the first end to generally the center of the shaft, and then gradually increase to the second end of the shaft.

Abstract: A bushing structure for switchgear includes first and second separate support structures (30, 32) each having surfaces defining at least one opening (48). The support structures are coupled together so that the openings define a passage (49) through the bushing structure and so that a slot (50) is defined between the first and second support structures, surrounding the passage. A bushing (40) is disposed in the passage and has a body (42), a bus receiving member (44), and a compression structure (45). The bus receiving member has an opening (46) there-through sized to receive a bus bar (28). When the first and second support structures are coupled together with the bushing in the passage, the compression structure is disposed in the slot, sandwiched between the first and second support structures so that they exert pressure on the compression structure.

Abstract: A rear panel for a draw-out circuit breaker includes a metal plate having a pair of rectangular cutouts. Two bushing blocks are joined together and at least partially extend through the cutouts. Each molded bushing block includes three bushings, each of which carry an electrical conductor that is over-molded therein.

Abstract: A containment system for internal arc generated gasses includes a compartment having an aperture through a wall thereof. A bus compartment includes an opening through a wall thereof. Arc chamber is in communication with the aperture and the opening. A vent flap member closes the opening and is moveable to an open position to permit gasses to flow through the opening into the arc chamber. Flap structure is associated with the apertore and includes a plurality of interconnected flaps for moving generally simultaneously from an open position, permitting gasses to flow through the aperture into the arc chamber, to a closed position, closing the aperture to prevent gasses from flowing through the aperture. The flap structure includes actuating structure coupled with the interconnected flaps. The vent flap member, when moved to the open position thereof, engages the actuating structure to move the interconnected flaps to the closed position thereof.

Abstract: A contact arm assembly (10) for a switchgear circuit breaker includes a contact arm (11) having a groove (42) in an outer periphery surface thereof. At least one contact finger (13) has a body (38) and a ball member (40) extending from the body. The ball member is received in the groove so that the contact finger makes contact with the contact arm. The contact arm includes a shaft (14) having a longitudinal axis, first and second ends (18, 28), and a constant outside diameter. A plurality of annular rings (16) extends from the outside diameter of the shaft. The rings are spaced along the longitudinal axis to define cooling fins. Diameters of the rings gradually decrease from the first end to generally the center of the shaft, and then gradually increase to the second end of the shaft.

Abstract: A truck (12?) for mounting a circuit breaker (13) in a switchgear frame (14?) includes wheels (16), a racking screw (20), a nut (22) threaded with the racking screw. The nut floats linearly with respect to the truck. A spring (23) is provided between a portion of the truck and the nut such that during movement of the truck into the frame, rotation of the racking screw causes linear movement of the nut, with the nut pushing against the spring, with the spring pushing the truck to move the truck linearly. Locking structure is coupled with the such that when the truck is stopped and the racking screw continues to rotate, the nut will move to compress the spring, causing the locking structure to move from an unlocked position, disengaged with the frame, to a locked position, engaged with the frame.

Abstract: An improved arc-resistant switchgear enclosure is disclosed. The disclosed arc-resistant switchgear enclosure provides a cost effective structure to collect and channel the pressure and hot exhaust gases from lower compartments and safely vent these gases through the switchgear enclosure. In preferred embodiments, an internal arc chamber is formed by assembling modules and creating a void within the center of the switchgear enclosure. As multiple compartments or modules for a switchgear enclosure are connected, an arc chamber is created within the enclosure. Upon initiation of an arc fault within a particular compartment, a relief flap or cover for that particular compartment opens to channel the pressure and the gases into the internal arc chamber or directly through the top of the enclosure. Pressure and gases are vented into the internal arc chamber and flow horizontally through the arc chamber until a path to the top of the switchgear enclosure is reached.

Abstract: An arc resistant enclosure including two compartments having a toggle flap which permits the two compartments to share a single exit path from the enclosure for any pressure and gases produced in either compartment.

Abstract: An improved arc-resistant switchgear enclosure is disclosed. The disclosed arc-resistant switchgear enclosure provides a cost effective structure to collect and channel the pressure and hot exhaust gases from lower compartments and safely vent these gases through the switchgear enclosure. In preferred embodiments, an internal arc chamber is formed by assembling modules and creating a void within the center of the switchgear enclosure. As multiple compartments or modules for a switchgear enclosure are connected, an arc chamber is created within the enclosure. Upon initiation of an arc fault within a particular compartment, a relief flap or cover for that particular compartment opens to channel the pressure and the gases into the internal arc chamber or directly through the top of the enclosure. Pressure and gases are vented into the internal arc chamber and flow horizontally through the arc chamber until a path to the top of the switchgear enclosure is reached.