Hitachi, Ltd.

Shikoku Electric Power Co., Inc.

Hitachi Cable, Inc.

Hideo Tsukioka

Katuo Sugawara

Etsunori Mori

Etsuo Ohe

Shigeo Shiono

Moriichi Sato

Seiichi Sakai

Toshihiko Gange

Ichitaro Tani

Ictitaro Tani

Masatsugu Ogata

Hisao Sonobe

Katsuo Sugawara

Masatoshi Seki

Sadayuki Okada

Akio Mitsuoka

Etsuo Oe

Ititaro Tani

Etuo Ohe

Method and apparatus for diagnosing abnormality of an oil-filled electric apparatus is disclosed. Presence or absence of abnormality is determined by comparing contents of plural predetermined components contained in gas extracted from the oil of the electric apparatus with respective predetermined reference values. The type of abnormality is determined on the basis of at least one set of two specific components selected from the plural components.

Method and apparatus for diagnosing oil-filled electric apparatus

A gas chromatographic apparatus having at least two gas separation columns arranged in parallel to each other, the outlet of the first gas separation column being connected to a gas sensor through a column switch valve, and the outlet of the second gas separation column being connected to the column switch valve through a gas detection time-controlling pipe, where when the first gas separation column is communicated with the gas sensor, the outlet of the second gas separation column is made open to the atmosphere by the column switch valve, or when the second gas separation column is communicated with the gas sensor, the outlet of the first gas separation column is made open to the atmosphere by the column switch valve, or the apparatus having a first gas separation column whose inlet is connected to the switch valve and at least two second columns whose inlets are connected to the outlet of the first gas separation column, whose outlets are connected to the gas sensor and which are arranged in parallel to each other through the column switch valve, where the first gas separation column, one of the second columns and the column switch valve are communicated with each other, by the column switch valve. A chromatogram with distinctly separated peaks in a continued state can be obtained in a short time by only one detecting and recording means.

Gas chromatographic apparatus

In an apparatus for detecting gas components in the oil in an oil-filled device, which comprises a gas-storing chamber being provided at an oil-filled device containing an insulating oil through a gas-permeating material capable of separating gas components from the insulating oil, a gas calibration tube being provided at the gas-storing chamber through a switch valve, and a gas chromatographic device connected to the gas calibration tube through the switch valve, any influence of gas components in a subatmospheric pressure is eliminated and exact concentrations of gas components are detected by providing at least one stirring mixer having at least one throttle perforation in a carrier gas passage for supplying the gas components from the gas calibration tube to the gas chromatographic device at the upstream side of a gas separation column of the gas chromatographic device, or by proving a circulation passage between the gas-storing chamber and the gas calibration tube, a valve capable of being exposed to the atmosphere at the circulation passage, and a gas circulation unit at the circulation passage for circulating the gas in the circulation passage.

Method and apparatus for detecting gas components in oil in oil-filled

A phosphoric triester containing at least one aromatic ring is mixed in an amount of 30 to 80% by weight based on the total constituents with a benzenetricarboxylic acid trialkyl ester or with a polyol ester obtained from trimethylolpropane and a saturated fatty acid to give a fire-retardant insulating oil.

Fire-retardant insulating oils

A system for monitoring an abnormality of an oil-filled electric device by detecting the components of the gas dissolved in the insulating oil. A gas-in-oil separator which separates the gas from the insulating oil, a gas reservoir where the separated gas is collected, an air feeder which supplies air for delivering out the gas in said gas reservoir, a separating column packed with a gas separating filler whereby the gas supplied from the gas reservoir is separated into the components, a combustible gas detector element disposed in a case which connects at its one end to the outlet of said separating column, and a change-over valve disposed at a location connecting said gas reservoir, are provided. The air feeder and said separating column are adapted to switch a route passing the air from the air feeder into the separating column along with the gas via the gas reservoir to or from a route passing the air directly into the separating column. This system is capable of easily detecting the components in the gas in the insulating oil to allow monitoring of an abnormality with high reliability. Also, according to the system of this invention, at least the components CH.sub. 4 and H.sub.2 in the separated gas are measured separately, and in case it is judged that an abnormality is present, the type of such abnormality is judged from the ratio of said components.

System for monitoring abnormality of oil-filled electric devices

In a self-bondable insulated wire comprising a conductor and three resin insulating layers, the first resin insulating layer is formed with a resin selected from the group consisting of polyimide resins, polyamideimide resins and polyesterimide resins, the intermediate resin insulating layer is formed with a resin selected from the group consisting of polyvinyl formal resins and epoxy resins, and the outermost resin insulating layer is formed with a self-bondable resin of phenoxy series. Thus, a self-bondable insulated wire which is excellent in both oil resistance and heat resistance is obtained.

Self-bondable insulated wires comprising three coatings including a

An apparatus for cooling a heat generating member by utilizing the latent heat of vaporization of a boiling refrigerant, having a cooling vessel including an evaporator section containing the boiling refrigerant and adapted to transmit the heat generated by the heat generating member to the refrigerant, and a condenser section for liquefying the gasified refrigerant; a liquid refrigerant reservoir open at its upper end and adapted to store a body of the refrigerant which does not directly take part in a cooling operation while the cooling operation is being performed; and a communication means for communicating the cooling vessel with the liquid refrigerant reservoir, the cooling vessel and the communication means being filled with the boiling refrigerant.

Open-type boiling cooling apparatus

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Mito, Japan

Hideo Tsukioka