Hitachi, Ltd.

Hideaki Uchiyama

Makoto Hirose

Toshiaki Rokunohe

Yuji Kaneko

Daisuke Nomura

Noriyuki Yaginuma

Masaru Tatemi

Hiroyuki Nakamichi

A symptom of malfunction regarding operating characteristics of a switch should be detected exactly. A switch operating characteristic monitoring device is comprised of a current sensor that measures a close command current of a switch, an auxiliary switch that outputs signals from at least two or more auxiliary contacts with reference to positions of a contactor, a measurement unit that measures signals from the current sensor and the auxiliary switch, a diagnosis unit that judges whether or not a malfunction occurs, and a display unit that displays a malfunction when a malfunction has been determined. A threshold is obtained in advance from multiple results of an opening/closing test performed beforehand. A calculation is made for characteristic times which are obtained from the close command current and signals from the auxiliary switch during actual operation of a circuit breaker. If a deviation is found by comparison with a threshold, a malfunction is determined.

Switch operating characteristic monitoring device, switch equipped with same, and switch operating characteristic monitoring method

A gas circuit breaker having a pair of contacts and a pair of exhaust conductors. An exhaust hole in the pair of exhaust conductors is provided with an insulation cover having an opening. The cover has a guide on an opening end on the side near the pair of contacts and an opening end on the side far from the pair of contacts respectively. The guide has an exhaust hole protective guide and a high-temperature gas passage dividing guide. A first gas flow passage is between an exhaust hole protective guide and a high-temperature gas passage dividing guide, and a second gas flow passage is between the high-temperature gas passage dividing guides. The first gas flow passage is narrower than the second gas flow passage. An end of the exhaust hole protective guide on the first gas flow passage side is projected toward the high-temperature gas passage dividing guide.

Gas circuit breaker

Growing community of inventors

Tokyo, Japan

Hideaki Uchiyama