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. 04, 1978
Filed:
Aug. 20, 1976
Tadashi Okawa, Hitachi, JP;
Yasuo Matsuda, Hitachi, JP;
Hiroshi Hayashida, Tokaimura, JP;
Takeo Maeda, Hitachi, JP;
Hitachi, Ltd., , JP;
Abstract
An induction motor is operated by a power supply of variable voltage and variable frequency. The voltage and frequency of the variable-voltage variable-frequency power supply is changed by a control circuit to accelerate or decelerate the induction motor. For slowly controlling the speed of the induction motor, the ratio of the output voltage to the output frequency of the variable-voltage variable-frequency power supply is maintained substantially constant. The control circuit includes a voltage correcting means which, in response to a command for sudden acceleration or deceleration of the speed of the motor, corrects the output voltage of the power supply in accordance with the acceleration or deceleration rate and the prevailing magnitude of the output frequency of the variable-voltage variable-frequency power supply.