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: A molded case circuit breaker having current limiting capabilities optimized for relatively smaller frame sizes. More specifically, one aspect of the invention relates to a two-piece carrier assembly for carrying the main and arcing contact arms which allows the main and arcing contacts to be blown open during short circuit conditions. The two-piece carrier assembly includes an inner carrier and an outer carrier pivotally connected together. The contact arms are carried by the inner carrier. When sufficient magnetic repulsion forces are exerted on the contacts due to a short circuit condition, the inner carrier pivots relative to the outer carrier to allow the contact arms to blow open. In order to control the amount of force required for blow open, a compression spring loaded cam assembly is provided.

Abstract: A positive off mechanism for a circuit breaker includes a pair of positive off levers slideable in slots in the side plates and extendable into the path of the operating handle to prevent movement of the handle to the off position when the contacts are welded closed. The positive off levers are actuated by positive off links pivotally mounted to the side plates and coupled to the positive off levers by "dog bone" connections. The positive off links in turn are actuated by the toggle mechanism of the circuit breaker which collapses to open the contacts during normal circuit breaker operation, but which remains erect when the contacts are welded closed.

Abstract: A molded case circuit breaker is provided with a pivotally mounted contact arm assembly, formed as a clinch joint. The contact arm assembly is a bifurcated assembly formed from two coextensive members fastened together at one end defining a surface for carrying a movable main contact. The other end of the members is bent outwardly defining spaced apart arm portions for receiving a pivot bracket. The pivot bracket is provided with an aperture and aligned with apertures in the spaced apart portions for receiving a pivot pin and defining a pivot axis. The pivot bracket is rigidly connected to a load conductor. The current that flows through the contact arm is transferred to bosses integrally formed adjacent the apertures in the pivot bracket. Screw adjustable spring members are provided for adjusting the friction and the electrical resistance between the contact surfaces of the contact arm assembly and the bosses.

Abstract: A molded case circuit breaker is provided with a line conductor having a U-shaped slot defining a pair of depending leg conducting portions and a peninsula portion. The U-shaped slot is adapted to receive a slot motor and also causes the current of the peninsula portion to flow in a direction opposite the direction of current flow in the movable contact arm to cause the contacts to be blown open during relatively high level overcurrent conditions. The peninsula portion is tapered outwardly, toward the base of the peninsula to increase the overall cross-sectional area of the conductor to minimize temperature rise. The tapered peninsula portion still allows a slot motor to be received in the U-shaped slot.

Abstract: A double-acting chemical operator drive assembly having a pair of pistons that are secured to the ends of a single piston rod and cooperate with a pair of power cylinders provide a positive drive for opening and closing the separable contacts of a circuit interrupter when the pistons are sequentially actuated by high-pressure gas generated by chemical propellant charges. The power cylinders are spaced apart and aligned with one another and the piston rod extends through open ends of the power cylinders. This eliminates the need for shaft seals and simplifies the manufacture and maintenance of the drive assembly. The operator drive assembly is coupled to the operating mechanism of the circuit interrupter by a yoke that is secured to an exposed medial part of the piston rod and then to a tie bar by a pair of drive rods.

Abstract: An actuator for an electrical circuit interrupter has a power cylinder for operating the circuit interrupter from a high pressure gas flow provided by a gas generating power unit which is a shotgun type shell container filled with a propellant. The propellant is characterized as being composed of spherical nitrocellulose grains having a nitroglycerin content; it is essentially free of deterrent coating and may have a granulation of 0.038/0.020 inches diameter range. Two suitable types are WC 630 or WC 615 manufactured by Olin Corporation of East Alton, Ill.

Abstract: An actuator for an electrical circuit interrupter utilizes a gas generating chemical charge which is carried in its own cylindrical operating chamber. These power units are stored in a magazine and are fed into an operating position by a transfer cylinder in the form of a rotary turret head having cylindrical cutouts for the power units. The operating position specifically is with a chamber juxtaposed opposite one of the two input ports of a duplex power cylinder which is connected to the operating linkages of the interrupter itself. After the power unit has operated to open the interrupter, it is ejected. The operating action is linked to a duplicate set of a storage magazine and transfer cylinder for the close direction so that while the interrupter is opening the duplicate close actuator portion is readied for instantaneous action. This provides for a fast reclosing duty cycle and multiple operations. Also, for high operating speeds and good reliability.

Abstract: An electric circuit interrupter comprising a pair of separable contacts, an operating mechanism for opening and closing the contacts and a drive mechanism including a cylinder-piston assembly and a gas pressure generator having multiple stationary combustion chambers and a directing device for selectively directing an expulsion of gaseous medium from any one of the multiple stationary combustion chambers.

Abstract: An electric circuit interrupter comprising a drive mechanism with a stationary drive piston and a movable drive cylinder for actuating an operating mechanism to selectively open and close a pair of separable contacts.

Abstract: A circuit breaker characterized by a pair of separable contacts, operating means for opening the contacts and comprising a cylinder and piston mechanism, closing means for closing the contacts and comprising a second cylinder and piston assembly operatively connected to the contacts.

Abstract: A circuit interrupter characterized by a pair of separable contacts, operating means for opening and closing the contacts and operatively connected to the contacts, drive means for driving the operating means and comprising a cylinder and piston, the piston having a piston rod extending from the cylinder on the side opposite the operating means, generating means for generating a sudden expulsion of gaseous medium into the cylinder and against the piston, and a connecting link comprising a yoke extending around the cylinder and connected on one side to the piston rod and on the other side to the drive means.

Abstract: An improved circuit-breaker position-indicator is provided for a gas-type circuit-interrupter in which the circuit-breaker structure is enclosed within an outer pressurized casing at a different pressure than the gas pressure interiorly of the circuit-breaker itself. Improved means are provided for effecting manual movement of the circuit-breaker contacts by a hand-jack assembly, when desired. Visible safe indication of the correct circuit-breaker open and closed-circuit positions is obtained at all times for safe and dependable operation of the circuit-breaker.

Abstract: An improved gas-heating means is provided for a multi-phase gas-type circuit-interrupter, all phases being supplied with high-pressure gas from a single high-pressure reservoir tank by suitable baffling means spaced longitudinally along the high-pressure reservoir tank, together with hot and cold inlet and outlet pipes leading into the separate upstanding circuit-breaker columns, or modules, controlling the individual phases, with the cold outlet pipe, preferably, extending downwardly toward the lower end of the high-pressure reservoir tank, and the hot inlet pipe located, preferably, at a higher elevational level than the cold outlet pipe, for thereby promoting proper heated gas circulation into the upstanding circuit-breaker modules.