Mitsubishi Electric Corporation

Mitsubishi Denki Kabushiki Kaisha

Kabushiki Kaisha Hattori Seiko

Mitsubishi Electronics Corporation

Noboru Hosokawa

Satoru Toyama

Eiichi Nagao

Junji Tanimura

Tsuyoshi Amimoto

Hirotaka Muto

Kiyoyuki Ishikawa

Kozo Tachibana

Kentaro Taninouchi

Akio Yamamoto

Tetsuya Matsuda

Takao Tsurimoto

Koji Kise

Soichiro Kainaga

Keiichi Ito

Ryuichi Nishiura

Takanori Sone

Fukutaro Kato

Taro Tanaka

Shunichi Kojima

Kosei Tsuji

Takahiko Ishikura

Yasuji Yoshizumi

Yasuo Toba

Koji Shinya

Hiroki Otera

Yoshio Kimura

Taketoshi Hasegawa

Haruyuki Shimayama

Provided is an apparatus for analyzing the state of oil-filled electrical devices. The apparatus simulates the state of an oil-filled electrical device in which copper wire wrapped in insulating paper is immersed in insulating oil. The apparatus for analyzing the state of oil-filled electrical devices includes a first paper-covered copper wire and a second paper-covered copper wire, which are adjacent to each other; a tank which holds the first and second paper-covered copper wires as well as insulating oil extracted from the oil-filled electrical device, thereby immersing the first and second paper-covered copper wires in the insulating oil; and a capacitance measurement unit which measures the capacitance between the first and second paper-covered copper wires. The first and second paper-covered copper wires includes copper wire and insulating paper wrapped therearound. The insulating paper wrapper around each copper wire includes the same material as the insulating paper in the oil-filled electrical device.

Apparatus and method for analyzing the state of oil-filled electrical devices

An object of the invention is to provide a diagnostic method for an oil-filled electrical device that considers a temperature distribution in the oil-filled electrical device and enables accurate diagnosis to be conducted even when the method is applied to diagnosis of an actually operating device, and further provide a method with which such diagnosis of an oil-filled electrical device can be conducted from a component analysis value of an insulating oil in the oil-filled electrical device. The invention is a diagnostic method for an oil-filled electrical device including in an insulating oil a metal part wrapped with insulating paper, and determines that a time when a surface resistivity of a maximum precipitation site where metal sulfide is most precipitated on the insulating paper reaches a preset surface resistivity management value is a time of occurrence of an abnormality.

Diagnostic method for oil-filled electrical device, diagnostic device for implementing the diagnostic method, and oil-filled electrical device provided with the diagnostic device

The present invention provides a method for inhibiting production of copper sulfide in an electrical insulating oil inside an oil-filled electrical apparatus, including adding a benzotriazole compound not having a long-chain alkyl group when the oil-filled electrical apparatus is an open-type oil-filled electrical apparatus, or adding a benzotriazole compound having a long-chain alkyl group when the oil-filled electrical apparatus is a closed-type oil-filled electrical apparatus.

Method for inhibiting generation of copper sulfide

In a stationary induction apparatus, an inter-partial-coil insulating plate and a plurality of inter-partial-coil spacer insulators form a refrigerant flow path in conjunction with each other. A space having an inter-partial-coil insulation dimension for withstanding an abnormal voltage is formed between a pair of partial coils. The inter-partial-coil insulating plate and the inter-partial-coil spacer insulators support both the pair of partial coils at an insulated state so as to maintain the inter-partial-coil insulation dimension. The insulators are arranged so as to be overlapped with each other in the direction in which mutually adjacent partial coils are opposed to each other.

Stationary induction apparatus

An oil immersed electrical apparatus such as an oil immersed transformer that can detect copper sulfide precipitated on coil insulating paper is provided. In the oil immersed transformer in which a coil with its surface covered by insulating paper is arranged in a container filled with insulating oil, a detection member is prepared by providing two electrodes on a surface of a plate-like pressboard formed of cellulose, which is a same material as that of the insulating paper, this detection member is arranged in contact with the insulating oil, and generation of copper sulfide is detected from reduction in a surface resistance between the electrodes. The temperature of the detection member is set higher than the temperature of the coil so that copper sulfide is generated thereon prior to generation of copper sulfide on a coil unit.

Oil immersed electrical apparatus

A stationary induction apparatus superior in insulating ability against a surge voltage includes a coil piece on a line end side surrounded by one electrostatic shield insulating layer. The coil piece and electrostatic shield insulating layer, together with another coil piece, are surrounded by another electrostatic shield insulating layer, thus forming a successively nested configuration. Each of the electrostatic shield insulating layers includes an electrical insulating layer of pressboard and first and second conductive layers respectively located on inner and outer surface sides of the electrical insulating layer, The capacitance of each of the electrostatic shield insulating layers is adjusted to control an electrical potential distribution upon application of a surge voltage.

A mechanism for connecting ornamental parts of wrist watches that permit easily connecting and disconnecting ornamental parts without using any special tool and without marring the appearance of wrist watches. A stepped pin is inserted in a larger-diameter bore of a cocoon-shaped ring fitted in an end piece and a bore in a watch casing. Then, a smaller-diameter part of the stepped pin is moved into a smaller-diameter bore by pulling the watch casing and a band longitudinally. With the stepped pin thus securely held in place, the watch casing and band are firmly connected.

Mechanism for connecting ornamental parts of wrist watch

Growing community of inventors

Chiyoda-ku, Japan

Noboru Hosokawa