Abstract: A method of manufacturing a semiconductor device having a super junction structure, includes: forming a first-conductivity-type semiconductor layer having a first surface and a second surface opposite to the first surface; forming a second-conductivity-type pillar region in the semiconductor layer; forming an insulating layer which covers the second surface of the semiconductor layer; forming a metal layer on the insulating layer; forming a gate electrode including a first opening passing through the metal layer by selectively removing the metal layer; and etching the insulating layer via the first opening, wherein the etching the insulating layer includes partially exposing the semiconductor layer by forming a second opening having a curved sidewall in the insulating layer by isotropic etching, and wherein an exposed surface of the semiconductor layer forms a flat surface continuous with the second surface of the semiconductor layer covered with the insulating layer.

Abstract: A gas circuit breaker includes a case body in which an insulating gas is enclosed, a stationary contact part accommodated in the case body and equipped with tulip type stationary contact members, and a movable contact part having a movable contact member. The movable contact member is rotated about a main shaft serving as a fulcrum and makes and breaks a contact with the stationary contacts member, so that a large capacity electrical line can be closed and opened at a high speed.

Abstract: There is provided an acr extinguishing device of a circuit breaker which closes and opens an electric line, one of two contact parts being fixed to a base part. The arc extinguishing device includes an arc runner formed of an electrically conductive member and arranged on an outer circumference of the above one of the two contact parts. The arc extinguishing device moves, to the arc runner, an arc occurring when a contact made by the two contact parts is opened whereby the arc is extinguished. The arc runner has a cylindrical shape and includes a rising portion formed on an entire inner circumference of the cylindrical shape. A slant angle of the rising portion obtained on a depth side thereof is greater than another slant angle thereof obtained on a front side thereof.

Abstract: An enclosed switchboard has a contact frame fitted with contacts which can move relative to a unit frame having a circuit breaker, an electromagnetic switch, and an auxiliary relay, etc. mounted thereon. The contacts can be operated to disconnected, test, and connected positions with the unit frame disposed in the panel frame by an operating lever inserted into a window on a closed door covering the front side of the panel frame. A shutter mechanism is provided between the window and the insertion position of the operating lever in order to cover the insertion position of the operating lever for preventing insertion of the operating lever when the operating handle is set to an ON position, and an interlocking mechanism is also provided between the shutter mechanism and the operating handle of a circuit breaker disposed at the unit frame.

Abstract: An enclosed switchboard has a contact frame fitted with contacts which can move relative to a unit frame having with a circuit breaker, a molded case circuir breaker, an electromagnetic switch, an auxiliary relay, a fuse, an earth fault relay, and a timer mounted thereon. This permits the operation of the contacts in disconnected, test, and connected positions with the unit frame loaded in fixed position in the panel frame. As a result, the front door of the panel frame can be closed even in the test and disconnected positions, preventing an electric shock during running and the emission of arcs and substances out of the panel in case of accidents, and avoiding dangers of injuries and damage due to collisions because of the passage being blocked with open doors, which consequently provides a safe switchboard. In addition, the need of removing and keeping the unit separately can be eliminated.