A switching mechanism with a vacuum circuit breaker between a bus bar and a cable connection stud. With this switching mechanism, the conductor parts forming the current path are coaxially arranged in an insulating oil bed surrounded by a tightly sealing outer sleeve of electrically conducting material and an inner sleeve of electrically insulating material. That end of the immovable contact of the vacuum circuit breaker which projects from the vacuum container is fastened to the inner conductor of the bus bar or collecting bar and extends transversely therefrom. The movable outer contact of the vacuum circuit breaker connected to the inner conductor of the cable connection stud is actuable axially via an insulating body. The electrically conducting outer sleeve has a rigid cylindrical tube with a branch for the cable connection stud and a T-shaped base part to receive a partial section of the inner conductor of the bus bar; a tubular outer hull piece of the bus bar or an end cover of the bus bar can be flanged to both arm pieces of the T-shaped base part of the cylindrical tube; the insulating oil bed separates the electrically conducting outer sleeve and the electrically insulated inner sleeve from each other; and the inner sleeve is designed as a support structure for the coaxial fixation of the conductor parts forming the current path.

An interrupter includes a vacuum enclosure for a set of high voltage contacts and end contact assemblies are secured to the end walls. High voltage terminals are connected to the contact assemblies. A solid insulating shell intimately attaches to the vacuum enclosure and extends axially therefrom to enclose the contact assemblies, with a contact shaft passageway in one end of the shell. One of the contact assemblies includes a movable contact shaft extending through the passageway in the insulating shell to an operating mechanism for rapid opening of the contacts. The passageway is sealed at the outer end to the shaft with a rolling diaphragm and defines a chamber encompassing the contact assembly. A deaerated insulating oil fills the chamber and significantly increases the impulse voltage rating of the interrupter. The chamber may alternatively be filled with a non-pressurized sulfur hexafluoride or other suitable gaseous medium to prevent contamination. A pressurized gaseous medium may also be used and increases the impulse voltage capability of the unit. If a pressurized medium is employed, the diaphragm is spring loaded to prevent ballooning.

A load interrupter device has a plurality of load interrupter contacts enclosed respectively in axially aligned vacuum bottles, each bottle containing a fixed contact and a second contact movable axially away from the fixed contact to open position and toward the fixed contact to closed position, the bottles being positioned in a tubular housing of dielectric material by a series of stacking pedestals each formed with three equi-angularly spaced radial arms engaging the inner surface of the tubular housing. Each movable contact is normally resiliently biased toward closed position and is moved to open position by a toggle having a pair of arms substantially aligned with the contacts and held in this position by springs connected to arms on the operating shaft such that when the operating shaft is rotated by the operating arm, the above-mentioned springs break the toggle, causing the individual contacts to open. A reset spring returns the operating shaft and operating arm to ready position and causes the toggle to return the contacts to their normal closed positions. The intermediate stacking pedestals by which the bottles are centered in the housing are anchored to the housing by stabilizing studs to eliminate excessive stresses in the vacuum bottle bellows and resultant maladjustment of the contact synchronism, and the stabilizing studs project outwardly through the housing to permit individual testing of each vacuum bottle.

A housing of a vacuum switch has in an upper connecting region a passage, through which the connecting element is led. The latter engages with its end region in a recess, opposite the passage, in the housing. In the region of the passage, the connecting element is supported on a support tongue and clamped tight by a wedge-shaped retaining member. The vacuum switch chamber is bolted on to the connecting element. The connecting element can also be secured to the housing at the support point opposite the passage.

A bus-mountable, circuit-interrupting device, including an interrupting unit and a novel line-potential, manually-resettable operating mechanism for the unit, is usable in circuits in which faults may exceed the interrupting capability of the unit. A normally engaged pair of contacts in the unit is separable within an arc-extinguishing medium. The operating mechanism includes a robust, stored-energy operator, for separating the contacts, and a tripping mechanism, which selectively releases the stored operating energy. The tripping mechanism normally prevents release of the stored operating energy, and includes a high mechanical advantage lever-link system which permits a low latching force to counteract the stored operating energy. A ratchet-solenoid combination in the tripping mechanism selectively removes the low latching force. If a circuit fault occurs, the solenoid moves an arm past, and moves, the ratchet in a first direction, which does not remove the low latching force, but rather stores energy capable of moving the arm in a second direction. Arm movement in the second direction, which occurs immediately in the case of a fault within the interrupting capability of the interrupting unit, moves the ratchet so as to remove the low latching force, permitting the stored operating energy to overcome the latch and move the lever-link system, thereby separating the contacts. If the fault exceeds the interrupting capability of the unit, the arm moves in the first direction, but is prevented from moving in the second direction until the circuit is otherwise opened, as by an upstream protective device.