Abstract: A power receiving unit is arranged in one side of an instrument potential/current unit transformer. A transformer-side unit is arranged in the other side of the instrument potential/current transformer units. A bypass bus connecting the power receiving unit and the transformer-side unit is arranged in parallel to the row of cubicles. The gas insulated switchgear can be made small in size and the work for adding a bank can be performed with substantially small man-power. The size of the gas insulated switchgear can be also prevented from increasing due to the addition of a bank.

Abstract: An interrupter unit comprising, an interrupter including at least two pairs of contacts, and an interrupter container surrounding the pairs of contacts, each of the pairs of contacts having a first contact and a second contact which contacts the first contact or is positioned away from the first contact so that electricity flows between the first contact and the second contact or is prevented from flowing between the first contact and the second contact, an electric actuator device for driving the pairs of contacts so that the second contacts contact the first contacts or are positioned away from the first contacts, and at least one voltage-transformer which transforms an input voltage and supplies a suitably transformed voltage to the electric actuator device so that the electric actuator device drives the pairs of contacts, wherein the interrupter unit further comprises an electrically grounded cover surrounding the interrupter and having first cover terminals which are electrically connected to the first c

Abstract: A gas-blast load-break switch comprises a pressure storage chamber for storing pressure of arc-extinguishing gas with arc energy generated by the disconnection between contacts, and a suction chamber including a piston which is moved in connection with the cut-off movement of the movable contact. A gas flowing device is provided such that the pressure raised by the arc energy is stored in the pressure storage chamber before communicating the pressure storage chamber and the suction chamber and a gas chamber formed on the opposite side of the piston from the suction chamber. The volume of the gas chamber is greater than that of the pressure storage chamber and the suction chamber, and the distance of piston movement in the suction chamber is longer than the contact length when the movable contact is thrown into the fixed contact.

Abstract: A switch provided with a negative pressure chamber which is actuated in association with the separating operation of a movable contact. The negative pressure chamber is connected to a means for supplying a fluid to the negative pressure chamber so as to suppress the negative pressure in the negative pressure chamber during the initial stage of the separaating operation of the movable contact.

Abstract: A switch apparatus for use in a distribution system, having a case, a pair of bushings arranged on the case so as to oppose each other, and a breaker arranged in the case such that breaking and closing actions take place in a direction perpendicular to an imaginary line interconnecting the pair of bushings. Both terminals of the breaker are connected to the corresponding bushings through conductors.