Hitachi, Ltd.

Hitachi Engineering Services Co., Ltd.

Yoshio Hamadate

Akira Yamagishi

Hiroyuki Fujita

Yasunori Ono

Kenichi Kawamura

Noriyuki Uchiyama

Sadamu Saito

Shouichi Yamamoto

Takeshi Nakayama

Mitsushi Abe

Akira Nishimizu

Toshiaki Rokunohe

Hiroyuki Watanabe

Jun Nukaga

Li Lu

Tomohiro Moriyama

Tomoo Chiba

Naoya Miyamoto

Kunihiro Takayama

Jun Kawamura

Mao Kawamoto

Youichirou Yamada

Hideyuki Miyahara

Yoshiaki Seya

A stationary induction apparatus includes a main body tank and a stationary induction apparatus main body. The main body is accommodated in the tank. An electrostatic shield ring is placed on the upper and lower end parts of a winding. An electrostatic shield ring has a magnetic ring and two insulating rings vertically fixing the magnetic ring for a spool. A conductive tape is laid on an insulating tape. These tapes are wound around the spool. An insulating tape is wound around the wound tapes. The width of the insulating tape is equal to or greater than the width of the conductive tape. One end of the conductive tape is connected to one end part of the winding and to the magnetic ring. A gap is provided at at least one place on the magnetic ring. The winding direction of the conductive tape is inverted at at least one place.

Stationary induction apparatus

To provide a safe stationary induction electrical apparatus that prevents a fragment coming off a magnetic shield, wound around an iron core leg portion of the stationary induction electrical apparatus, due to vibrations from being released in a tank accommodating the stationary induction electrical apparatus and thus prevents a trouble such as dielectric breakdown. Moreover, to provide a stationary induction electrical apparatus that does not need to be changed in the dimensions of an iron core for securing an insulation distance due to the placement of a magnetic shield and can reduce a compressive force generated in a winding. A magnetic material is provided in the interiors of insulating members whose interiors are hollow and which are provided in the vicinities of upper and lower ends of the winding wound around the iron core leg portion of the stationary induction electrical apparatus.

Stationary induction electrical apparatus

There is provided a diagnosing device for an on-load tap changing apparatus of a transformer, which can diagnose the degradation degree of insulating oil at high accuracy by a relatively simple device configuration. A diagnosing device for an on-load tap changing apparatus has an insulating oil tank in which insulating oil is sealed, a changeover switching device that is disposed within the insulating oil tank and performs the tap changing operation of a tap winding, a tap selector that selects the tap position of the tap winding, and a polarity (transposition) changer that inverts the polarity of the tap winding or a winding connected to the tap winding. The diagnosing device includes an arc discharge light detector that detects arc discharge light that is emitted at changing the tap position of the tap selector. The degradation degree of the insulating oil is diagnosed based on the arc discharge light detected by the arc discharge light detector.

Diagnosing device for on-load tap changing apparatus, diagnosing method for on-load tap changing apparatus, and diagnosing device for transformer

Disclosed is a power switch gear that includes: a fixed electrode and a movable electrode disposed opposite to each other in a tank filled with insulting gas; and a movable conductor electrically connecting the fixed electrode and the movable electrode together. The fixed electrode and the movable electrode have a contactor through which current flows to the movable conductor. At least one of the fixed electrode and the movable electrode has ring-shaped sliding members, the ring-shaped sliding members being disposed, on both sides of the contactor. At least one grease pool is provided between the contactor and the sliding members.

Power switchgear

A superconducting magnet apparatus obtains high magnetic field uniformity without increasing the volume of a magnetic material even against disturbances. The superconducting magnet apparatus has a circular superconducting coil which generates a magnetic field; a coil vessel which contains the superconducting coiltogether with refrigerant; a thermal shield arranged so as to surround the coil vessel; a vacuum vessel with inside kept vacuum which surrounds the thermal-shield; and magnetic materials and for correcting the magnetic field, the magnetic materials being arranged in the vacuum vessel; wherein the magnetic materials and are supported by a heat-insulation support medium fixed to the coil vessel.

Superconducting magnet apparatus and magnetic resonance imaging apparatus

Leakage fluxes from windings and leads of a stationary induction apparatus are confined within a tank. The stationary induction apparatus includes an electric functional units each including a winding and a core, a tank containing the electric functional units, high-voltage leads leading out from the windings, and low-voltage leads leading out from the windings. Magnetic shields are placed on the inner surface of a wall of the tank through which the high-voltage leads are drawn out of the tank, and a composite shield formed by combining nonmagnetic shields and magnetic shields is placed on the inner surface of a wall of the tank facing the low-voltage leads and is electrically short-circuited.

Growing community of inventors

Tokyo, Japan

Yoshio Hamadate