Mitsubishi Denki Kabushiki Kaisha

Takeo Yoshioka

Tadao Minagawa

Masahiro Kobayashi

Kenichi Mori

Toshihiro Suzuki

Kenro Mitsuda

Shiro Yamauchi

Nobuyoshi Takahashi

Toshiaki Murahashi

Yoshifumi Matsushita

Ichiro Yamasaki

Katsu Ujita

Takashi Kameda

Masahiro Ashiya

An oxygen concentration controlling element where the shortest distance between the anode and cathode separated by a solid electrolyte film is set not larger than 50 .mu.m, thereby to accelerate the back-diffusion of water generated in the cathode to the anode and dispense with a tank or a pump for supplying water to the anode. An oxygen concentration or humidity controlling apparatus where a photoelectric element is disposed at an opening of a to-be-controlled space to the atmospheric air and the electric energy from the photoelectric element is accumulated in a secondary battery, thus realizing space-saving apparatus which can operate continuously though the power is turned off, and a humidity controlling apparatus functioning both as a humidifier and as a dehumidifier.

Oxygen concentration or humidity controlling apparatus

A boiling type cooling device for cooling power semiconductors includes an evaporator containing an aqueous solution of ethylene glycol as a cooling medium, a condenser; and a vapor and liquid return pipe. According to a first aspect, the lowest portion of the condensor is at a level higher than the top surface of the cooling medium in the evaporator, the bottom surfaces of the condensor being tilted downward toward the top end of the liquid return pipe. According to another aspect, a pump is provided in the liquid return pipe for driving cooling medium to the evaporator. According to still other aspects, the liquid return pipe is covered with a heat insulating material, or a rubber string extends centrally therewithin. A deaeration device for the aqueous solution of ethylene glycol includes two separate deaeration baths and a mixing bath.

Cooling device for power semiconductor switching elements

A lightning arrester monitor which consists of an oxygen gas sensor provided in a lightning arrester having a zinc-oxide-type element made of zinc oxide, the main component thereof, and other oxides added thereto, the oxygen gas sensor measures the oxygen concentration of the element which increases as degradation thereof goes on. The monitor makes it possible to assess degradation of the zinc-oxide-type element with ease, without requiring any complicated electrical circuit for detecting leakage current.

Lightning arrester monitor

An element for detecting internal faults in an insulating gas charged electrical apparatus comprises a substrate disposed in the electrical apparatus charged with an insulating gas, a pair of electrodes disposed on the substrate, and a thin metal film covering the pair of electrodes and the exposed surface of the substrate. This film is capable of producing fluorides with low conductivity upon reacting with a decomposed gas produced by internal faults of the electrical apparatus. Since the thin metal film exhibits high response characteristics readily in reaction with even a trace amount of a decomposed gas, it is possible to promptly detect faults occurring in the electrical apparatus, such as a partial discharge or local heating. In addition, a device for detecting internal faults in an insulating gas charge electrical apparatus using the internal fault detection element utilizes an optical signal for transmitting signals. Accordingly, the device is free from electromagnetically induced interference and is capable of remote monitoring because of the low level of loss in signal transmission.

Element and device for detecting internal faults in an insulating gas

An abnormal condition detector detects an abnormal condition of an electric apparatus by sampling an insulating fluid filled in the electric apparatus under a pressurized condition and detecting a change of the condition of an indicator induced by an acidic gas in the sampled insulating fluid.

Abnormal condition detector of electric apparatus

Growing community of inventors

Amagasaki, Japan

Takeo Yoshioka