Hitachi, Ltd.

Other

Hitachi Engineering Services Co., Ltd.

Yozo Shibata

Ayumu Morita

Toru Tanimizu

Tooru Tanimizu

Yasuaki Suzuki

Masato Yabu

Takashi Kadowaki

Masato Kobayashi

Yoshimi Hakamata

Shuichi Kikukawa

Minoru Suzuki

Katsunori Kojima

Naoki Nakatsugawa

Yoshitomo Gotoh

Makoto Terai

Takuya Okada

Satoru Kajiwara

Yoshiyasu Watanabe

Mitsuji Konishi

An electromagnet a coil, a movable iron core adapted to move on the center axis of the coil, and a stationary iron core provided so as to cover the upper and lower surfaces and the outer peripheral surface of the coil. A permanent magnet is arranged in a gap surrounded by the movable iron core and the stationary core.

Electromagnet and actuating mechanism for switch device, using thereof

An electromagnet includes a coil, a movable iron core adapted to move on the center axis of the coil, and a stationary iron core provided so as to cover the upper and lower surfaces and the outer peripheral surface of the coil. A permanent magnet is arranged in a gap surrounded by the movable iron core and the stationary core.

A vacuum switch gear provided with a vacuum container grounded within a grounded vacuum container or a gas-insulated ground container, and a pair of buses connected to an external conductor of the switch gear. A portion for connecting the buses and the external conductor is interface insulation in which an elastic body and solid insulation are utilized in combination. The interface insulation performs adhering and tightening work by rotating an adjuster from the outside.

Vacuum switchgear

There is disclosed a vacuum insulation switch provided with a movable electrode, a stationary electrode and an earthing electrode, which are insulated from each other, in a vacuum container made of a conductive material which is earthed, and a switchgear using the same. Since the vacuum insulation, which is excellent in the insulation ability, is utilized, the switch is drastically miniaturized and the number of constituent parts are reduced, whereby the manufacturing cost of the switch and the switchgear can be decreased.

Vacuum switch and a vacuum switchgear using the same

A vacuum insulation switch provided with a movable electrode, a stationary electrode and an earthing electrode, which are insulated from each other, in a vacuum container made of a conductive material which is earthed, and a switchgear using the same.

Disclosed is a method of controlling the operation of a plurality of compressors each having at least one capacity controller capable of changing the discharge rate of the compressor in a stepped manner in such a manner as to provide a total discharge rate just meeting the load demand which varies momentarily. In this method, the control system is divided into a capacity control loop for responding to comparatively small load variance and a compressor control loop for responding to a comparatively large load variance. The capacity control loop is further divided into a sub-loop for capacity controllers of a compressor which has worked longest and which is to be stopped first and a sub-loop for the capacity controllers of other compressors. The unloading operation is commenced preferentially with the sub-loop for the capacity controllers of the compressor to be stopped first, while the on-loading operation is made first with the sub-loop for the capacity controllers of other compressors.

Method of controlling operation of a plurality of compressors

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Hitachi, Japan

Yozo Shibata