Abstract: Switchgear is provided including an enclosure for pad-mounted installation. The enclosure includes large lift-up cover panels in combination with removable front panels so as to provide unobstructed access to the interior of the enclosure. In a preferred arrangement, the enclosure houses switchgear that includes low-voltage control and viewing arrangements that are operable from a first side of the switchgear and medium-voltage cable terminations that are accessible from a second side of the switchgear opposite the first side, the enclosure providing access to the low-voltage arrangements while providing isolation from the medium-voltage arrangements. The enclosure also includes protection from the environment in the area of the lift-up cover panels while also providing collapsible lifting members.

Abstract: A fusible element is provided that includes cooperating interfitting parts surrounded by fusible material. The cooperating interfitting parts are arranged so as to place compressive force on the fusible material in response to attempted separation of the interfitting parts. Further, the arrangement also reduces the forces on the fusible material. In response to a predetermined time-current condition, the fusible material softens sufficiently to permit the release and separation of the interfitting parts.

Abstract: A gang-operated multi-pole switch is provided including an operating handle suitable for manual operation via a hookstick and including an open-position retention arrangement. The open-position retention arrangement includes a first member movable with the operating handle which coacts with a second member. In a preferred arrangement, the first member extends radially from the operating shaft of the operating handle and the second member is a spring plate including a retention surface and disposed in the path of the first member.

Abstract: An operation selector arrangement is provided for an operating mechanism that is controlled by movement of an operating shaft between the operational positions. Blocking features are provided for preventing operation between predetermined operational positions without first manipulating the blocking features. In a preferred arrangement, a an operating handle is utilized to operate the operation selector arrangement. A blocking member prevents operation of an operation selector between two operating positions without first stopping at an intermediate position, removing the operating handle, moving the blocking member, and then reinserting the handle. The blocking member is separately securable from the operation selector such that personnel may be authorized to operate the operation selector while other personnel are additionally authorized to manipulate the blocking member.

Abstract: A control arrangement and method is provided for high-speed source-transfer switching systems (HSSTSS). The HSSTSS supplies an electrical load with alternating current from either a first source or a second source via respective first and second solid-state switches. The HSSTSS also includes a controller that samples the voltage waveforms of each of the first and second sources to detect when transfer between the sources is desirable, e.g. outages or voltage that is either too low or too high. The controller provides appropriate control signals to control operation of the solid-state switches and transfer supply of the load therebetween. The control arrangement avoids undesirable current flow between sources via a comparison of the voltages of the sources and current in the outgoing source, i.e. a polarity comparison to ensure that the current that will flow in the incoming source after transfer will be in opposition to the current flowing in the outgoing source before transfer.

Abstract: An arrangement capable of being assembled with either an existing installed electrical equipment enclosure or during the fabrication and assembly of the electrical equipment enclosure is provided that increases the ventilation characteristics of the electrical equipment enclosure and provides desirable tamper resistance. The electrical equipment enclosure includes at least one sidewall, at least one access panel carried by the sidewall, at least one support member spanning portions of the sidewall, and a roof being carried above the sidewall and the access panel. The sidewall, the access panel, the roof and the support member including predetermined turned edges forming flanges and being assembled so as to define predetermined passageways therebetween which provide predetermined ventilation characteristics and tamper resistance characteristics.

Abstract: An arrangement is provided to power and initiate the output of information sensed and/or stored by a device in a sealed environment having a viewing window. The device is powered and the output is initiated by the input of a light source to the device. When the output is initiated, the device provides a display representing the information. In a specific arrangement, the device scrolls to display the information on a sequential, repetitive basis while the light source is directed onto the device. In one specific embodiment, the device is powered by a solar cell or the like. In one specific application of the invention, the information represents the real-time primary voltage of components and circuitry within the switchgear. In another specific application of the invention, the device is located within a sealed switchgear enclosure and the information represents the faulted phase or phases of the power distribution circuit to which the switchgear is connected.

Abstract: A control circuit and method are provided for a circuit interrupter that predicts the occurrence of fault-current zero crossings. This prediction is utilized to control the operation of a circuit interrupter at a desirable point in the periodic wave form of the fault current. For example, the control circuit is useful to control a synchronous interrupter by accurately generating a trip signal to the synchronous interrupter for operation in the vicinity of the zero crossing of the current wave form. In a preferred arrangement, the control circuit utilizes the quotient of a sensed current signal and the time rate of change of the sensed current signal. In one specific arrangement for circuit environments that might include conditions that could lead to false results, the time rate of change of the quotient is utilized to provide a control signal.

Abstract: An operating mechanism that provides multiple operational output states at a first output and additional operational output states at a second output that are synchronized with the first output to provide a predetermined sequence of control. The operating mechanism includes an output lever that is pivoted by the stored energy in a spring and latch levers that are selectively operated to release the output lever. When the output lever is moved between operational positions, the output lever is stopped in its pivoting movement via the latch levers.

Abstract: A circuit-interrupting device for electrical power distribution and transmission systems is provided having improved handling provisions for removal and installation with respect to conventional mountings. The handling provisions permit the circuit-interrupting device to pivot about the lower hinge of the mounting before the circuit-interrupting device is lifted out of the mounting via a handling tool. This permits the dimensions of the circuit-interrupting device to be greater than conventional circuit-interrupting devices. For example, in a preferred embodiment, the circuit-interrupting device includes exhaust diverter structure which directs exhaust away from the mounting, the exhaust diverter structure extending beyond the maximum dimensions which allow the circuit-interrupting device to be directly lifted out of the mounting hinge, i.e. the exhaust diverter structure interferes with the mounting if the circuit-interrupting device is lifted in a direction out of the mounting.

Abstract: A handling-tool fitting is provided for use in the removal and installation of overhead mounted devices in power distribution and transmission circuits, the handling-tool fitting including a curled prong having a first, substantially straight portion and a second, cured portion that is inclined upwardly with respect to the first portion. The handling-tool fitting is inserted through a loop of the device, the loop being supposed in a stable manner on the first portion of the handling-tool fitting and the second portion preventing any movement of the loop of the device away from the first portion.

Abstract: A current-limiting device is provided having a low profile configuration (generally flat polyhedron) that defines a cavity of predetermined dimensions and an elongated circuitous path through the cavity. The device also includes provisions for supporting a current-limiting fusible element along the path. The cavity is filled with a pulverulent arc-quenching filler material. In one specific arrangement, the path of the fusible element is defined by one or more U-shaped sections substantially spanning the length or width of the cavity. The fusible element is arranged in a predetermined geometry to include a length of the fusible element that is longer than the overall straight-line path via a configuration of steps or bends along its length.

Abstract: A flexible connection arrangement is provided for two conductors that accommodates all possible forms of misalignment between the two conductors. The connection arrangement utilizes spherical joints formed by facing hemispherical protuberances at each end of two movable links.

Abstract: A low-exhaust composite drop-out assembly is provided that is utilizable in a standard cutout mounting in electrical power distribution systems. The composite drop-out assembly includes current-limiting and low-current clearing sections and is easily removable from mounting for servicing. The sections are efficiently arranged in a side by side configuration.. The low-current clearing section includes a fuse-robe assembly having a replaceable fuse cartridge. Accordingly, the low-current clearing section is simply and economically renewable for reuse whether or not the current-limiting section has operated. Further, the current-limiting section need not be replaced if only the low-current clearing section operated in response to overcurrent in a low range. Additionally, the sections are separable so that the low-current clearing section can be reused after simple refusing even when the current-limiting section has operated.

Abstract: A contact arrangement is provided for engaging first and second stationary contacts in a predetermined sequential manner, for example so as to appropriately provide a pre-insertion function via the first contact and prior to engagement of the second contact that provides a circuit-closing function in a main current path. In a preferred arrangement, the moving contact of the contact arrangement includes first and second contact surfaces that are spaced apart and parallel to each other, the first and second contact surfaces of the moving contact sequentially engaging the first and second stationary contact surfaces respectively during closing movement. In a specific embodiment, the first and second contact surfaces are provided by a unitary contact member having a circular cross-section, this arrangement being especially suited for a switch where the contact member is rotated as it moves to the closed position.

Abstract: A current-limiting device is provided having a low profile configuration (generally flat polyhedron) that defines a cavity of predetermined dimensions and an elongated circuitous path through the cavity. The device also includes provisions for supporting a current-limiting fusible element along the path. The cavity is filled with a pulverulent arc-quenching filler material. In one specific arrangement, the path of the fusible element is defined by one or more U-shaped sections substantially spanning the length or width of the cavity. The fusible element is arranged in a predetermined geometry to include a length of the fusible element that is longer than the overall straight-line path via a configuration of steps or bends along its length.

Abstract: A switchgear module is provided that is assembled from one or more molded housing portions to provide a gas-tight volume for the housing of electrical components. The switchgear modules include provisions for assembly of various combinations of switchgear modules into a variety of electrical circuit configurations while maintaining a gas seal of the switchgear modules. In a preferred arrangement, the switchgear module includes bus conductors that are integrally incorporated during the molding of the switchgear module housing and that are accessible from opposite sides of the module. Further, the switchgear module includes integrally molded features for providing access to make electrical interconnections between the bus conductors of adjacently positioned switchgear modules.