Mitsubishi Denki Kabushiki Kaisha

Tatsunao Hayashida

Takashi Watanabe

Toshiyasu Higuma

Haruhiko Ishida

Akihiko Imagi

Toyohiro Kobayashi

Yoshio Yoshikuwa

Yoshinori Numano

Akihiro Kobayashi

Yasunori Shida

Kenshi Kawagishi

Kazuyuki Mitsushima

Hidekazu Totsuka

Shoji Mukohara

Yukihiko Iwata

Osamu Kamiya

Yu Hasegawa

Norikazu Ishikawa

Takuo Akiyama

A multi-air-conditioner includes an exterior unit, interior units and remote-controllers. The exterior unit collects operation data of each of the interior units, determines an operation condition, and transmits the operation condition to each of the interior units. The interior units transmit the operation condition to the exterior unit, receive the operation condition from the exterior units, receive the operation setting condition from the remote-controllers, set an operation condition based on the operation setting condition which is received from the remote-controllers and the exterior unit, and transmit the operation condition to the remote-controllers. The remote-controller receives the operation condition from the interior units and transmits the operation setting condition to the interior units.

Air-conditioner

The improved motor drive unit includes a zero-crossing voltage detector circuit composed of components (7) to (12) for detecting whether the voltage from an AC power supply (1) is zero-crossing and a switching circuit for performing on-off control by means of a thyristor 27 so as to switch between energization and de-energization of the AC power supply to a motor (2) and controls the speed of the motor by changing the ratio between the times of energization and de-energization of the AC power supply to the motor. The start of energization coincides with the zero-crossing of the AC power supply voltage whereas the timing of end of energization coincides with the zero-crossing of an energization current by means of the thyristor and wherein the energization time is fixed at a value either equal to or twice the power supply period whereas the de-energization time is varied in units that are integral multiples of one half the power supply period. If desired, a plurality of patterns for percent energization may be combined to attain a desired percent energization. Alternatively, a plurality of patterns that are equal in the ratio between the energization and de-energization times are used in combination. Only the main winding in the motor is preferably controlled for optimal energization.

Motor unit, motor drive unit, fan unit and method of controlling the

In an optical communications apparatus of one office having a light sending device which has a plurality of coupling ends adapted to be coupled with a light transmitting optical fiber for connecting individual offices and which sends a transmission signal in the form of light, and a light receiving device which receives a light signal; an optical communications apparatus comprising light sending means connecting the respective coupling ends and the light sending device through optical fibers, light receiving means connecting the respective coupling ends and the light receiving device through optical fibers, and pass-through means for passing the light signals between the coupling ends.

Optical communications apparatus

Growing community of inventors

Shizuoka, Japan

Tatsunao Hayashida