Hitachi, Ltd.

Japan Servo Co.,ltd.

Masahiko Fujita

Toshihiko Gotoh

Kenji Hayashi

Tsutomu Nakamura

Toshihiko Fukushima

Seigo Miyamoto

Shinji Ozaki

Kosaku Sayo

Kazutoshi Konno

Tooru Fujishima

Hiroshi Hagino

Kazuyoshi Kuwahara

Hayato Hatanaka

Naoto Nishimura

Teyon Shin

Masanori Musoo

Sealed chamber for monitoring pressureis provided on sealed tank. Sealed tankis filled with insulating gas. And, a connection using insulated pipeis provided between medium-pressure spacethat makes a medium pressure and sealed chamber for monitoring pressure. In sealed chamber for monitoring pressure, a pressure monitoring and controlling means is provided for monitoring the internal pressure thereof to activate the pressure-release control in response to the situation where the monitored internal pressure has reached the predetermined setting value. The pressure monitoring and controlling means includes solenoid valvethat is capable of opening sealed chamber for monitoring pressureto the atmosphere, pressure detectorthat detects the internal pressure, and pressure monitor, which activates solenoid valvefor pressure-release when pressure detectordetects that the internal pressure has reached the predetermined abnormal pressure value.

Gas-insulated vacuum circuit breaker

A refrigerant flow rate control device for the refrigeration cycle of an air conditioning system of an automotive vehicle which is driven by a vacuum actuator includes a communication passageway for equalizing pressures applied to opposite ends of a valve body. The valve body has an intermediate portion maintained in communication with the atmosphere and connected to the vacuum actuator.

Refrigerant flow rate control device

A tape drive device in which a cavity is formed in a reel hub provided for supplying or taking up a tape-shaped information recording and reproducing medium such as a magnetic tape or a film. A motor including a rotor unit and a stator unit is partly or wholly received within the cavity of the reel hub, and the rotating force generated by the rotor part of the motor is transmitted directly or through a reduction gearing to the reel hub to cause rotation of the reel hub.

Tape drive device

An electric motor having a rotor consisting of a disk-shaped multi-polar magnet circumferentially sectioned to have a plurality of magnetic poles, a stator consisting of a pair of superimposed star-shaped flat driving coils, said driving coils being disposed facing said magnet, said driving coils being arranged to be supplied with respective alternating currents having a phase differential of 90.degree. thereby to drive the disk-shaped magnet, said motor further comprising a speed detecting coil having a plurality of radially disposed generating wire elements, said generating wire elements being disposed within a magnetic field of said magnet and being connected in series, whereby a signal having a frequency corresponding to the revolution speed of said disk-shaped magnet is induced in said speed detecting coil.

Electric motor having frequency generator

An electric motor comprises a rotor constructed by a disk-shaped multi-pole magnet secured to a rotary shaft and rotatably supported, and a stator constructed by a pair of star-shaped flat drive coils arranged adjacent and opposing to the disk-shaped multi-pole magnet. Sinusoidal wave currents, the phase angles of which differ by 90.degree. from each other, are supplied to the pair of drive coils to drive the magnet. A speed detection coil having a plurality of power generating strands is arranged in a field of the magnet and a field of the drive coils to produce a signal having a frequency corresponding to a rotational speed of the magnet. A cancellation coil is also arranged in the field of the drive coils to produce a voltage which varies with the change of the drive coils, which voltage is added to an output signal from the speed detection coil to cancel out a signal developed across the speed detection coil by the change of the drive field so that a speed detection signal of a high S/N ratio is derived to enable the control of the rotation of the electric motor.

Electric motor

A video signal reproducing system comprising means for driving a web of recording medium such as a tape at a constant speed, a self-scanned linear photoelectronic image device disposed for scanning in a direction perpendicular to the traveling direction of the recording medium, a clock pulse generator for applying clock pulses to this image device, and a light source for illuminating the recording medium, whereby information optically recorded on the recording medium can be scanned in a two-dimensional fashion to reproduce a video signal such as a television signal.

Video signal reproducing system

Growing community of inventors

Yokohama, Japan

Masahiko Fujita