Mitsubishi Denki Kabushiki Kaisha

The Kansai Electric Power Co., Inc.

Ken Kimura

Kenji Morimoto

Yoshiharu Kaneda

Shigeo Kitamura

Tetsu Shiota

Keiichi Itoh

Takaho Tanaka

Hideki Tokura

Takeshi Kawakami

Hiroyuki Nakajima

Akinobu Tamaki

Masakazu Murayama

Yasuko Ohno

Eiki Zidai

Masao Irie

A defect detecting apparatus for monitoring an electrical equipment for defects, the electrical equipment having a resonance frequency. The defect detecting apparatus includes a sensor operatively connected to the electrical equipment for sensing a signal indicating a defect in the electrical equipment; a first bandpass filter operatively connected to the sensor, the first bandpass filter having a first bandwidth and first center frequency at substantially the resonance frequency of the electrical equipment; a second bandpass filter operatively connected to the sensor, the second bandpass filter having a second bandwidth and a second center frequency higher than the resonance frequency of the electrical equipment; a signal strength comparing circuit operatively connected to the first bandpass filter and the second bandpass filter for comparing relative strengths of signals output by the first bandpass filter and the second bandpass filter; and a partial discharge measuring circuit operatively connected to the signal strength comparing circuit for measuring an output signal of the first bandpass filter relative to an output signal of the second bandpass filter to indicate a defect in the electrical equipment.

Abnormality detecting method and apparatus for electrical equipment,

An abnormality detecting method and apparatus for electrical equipment measures the frequency spectrum of a signal detected by a partial discharge sensor and detects a partial discharge signal having a frequency component in the neighborhood of a resonance frequency to detect the abnormality of the electrical equipment. The resonance frequency is determined on the basis of the electrical equipment and the measuring circuit. Where the electrical equipment is a rotating electric machine, the resonance frequency is determined on the basis of the length of the stator core, and a narrow bandpass filter circuit passes a frequency component around a resonance frequency to detect a partial discharge signal from the passed signal.

Abnormality detecting apparatus for electric equipment, particularly for

The abnormality detecting method and apparatus for electric equipment measure the frequency spectrum of a signal detected by a partial discharge sensor 9, and detect a partial discharge signal having a frequency component in the neighborhood of a resonance frequency determined on the basis of the electric equipment and its measuring circuit, then detect the abnormality of the electric equipment. In a rotating electric machine particularly, the narrow band filter circuit 23 passes a frequency component around a resonance frequency determined on the basis of the length of the stator core to detect a partial discharge signal from the passed signal.

Abnormality detecting method and apparatus for electric equipment,

A thermosetting insulating resin paste including 100 parts by weight of an epoxy resin containing a diglycidyl type liquid epoxy resin as a main component and based on the parts by weight of the epoxy resin, 0.5 to 10 parts by weight of dicyandiamide as a setting agent. It further contains 1 to 15 parts by weight of a phenoxy resin, 0.1 to 8 parts by weight of 2-phenyl-4-methyl-5-hydroxymethylimidazole and/or 2-phenyl-4,5-dihydroxymethylimidazole as a setting accelerator as well as 50 to 200 parts by weight of a thermally conductive filler. This insulating resin paste exhibits a long pot life and can be set in a short time at a low temperature without generating any voids during the setting, so that it enables the die bonding process in the production of semiconductor devices to be performed as part of the production line. It also allows a smaller device to be used in this process.

Thermosetting insulating resin paste

A method for insulating a coil of a rotary electric machine resulting in improved insulating properties at critical coil ends. A mica sheet or mica tape is wound around a part of each coil to be inserted into a slot cut in an iron core of the rotary electric machine to thus form a first insulating layer. The coils thus treated are inserted into respective slots and are connected together and to external terminals as required. Each coil end is then covered in its entirety with a thermosetting resin. The thermosetting resin is hardened by heating to form a second insulating layer.

Insulating method for rotary electric machine

Growing community of inventors

Hyogo, Japan

Ken Kimura