Kabushiki Kaisha Toshiba

Norikazu Arima

Susumu Nagano

Hiromichi Ito

Yukio Kanazawa

Shinobu Sekito

Takeshi Tanii

Makoto Tari

A remaining life of a stator coil resulting from galvanic corrosion between different kinds of metals in a rotating machine adopting a water cooling system and remaining life of a stator coil's insulating layer resulting from a wet heat degeneration can be positively and integrally evaluated according to the present invention by sampling a brazing section between the stator coil clip and copper wires, cutting off the sampled brazing section in a copper wire array direction, measuring a joined section brazed with a brazing material as a copper wire direction length and finding an effective sealing length of that brazing section or sampling an insulating layer of the stator coil, finding infrared spectra of the insulating layer, comparing the infrared spectra of the insulating layer of the stator coil with infrared spectra of a healthy stator coil's insulating layer not penetrated by water, finding difference spectra of an ester group of an epoxy resin used as a bonding agent of the insulating layer and predicting a period of water penetration into the stator coil's insulating layer as a wet heat degeneration period, on the basis of the difference spectra of an ester group, with the use of a relation between the difference spectra of the ester group initially found and an aging time.

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Sagamihara, Japan

Norikazu Arima