The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 22, 1997
Filed:
Jun. 07, 1995
Akihiko Imagi, Hyogo, JP;
Yoshio Yoshikuwa, Hyogo, JP;
Takuo Akiyama, Shizuoka, JP;
Norikazu Ishikawa, Shizuoka, JP;
Tatsunao Hayashida, Shizuoka, JP;
Yu Hasegawa, Shizuoka, JP;
Kenshi Kawagishi, Shizuoka, JP;
Kazuyuki Mitsushima, Shizuoka, JP;
Haruhiko Ishida, Shizuoka, JP;
Hidekazu Totsuka, Shizuoka, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
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.