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:
Dec. 25, 1984
Filed:
Aug. 10, 1982
Tokunosuke Tanamachi, Katsuta,, JP;
Hiroshi Narita, Katsuta,, JP;
Masahiko Ibamoto, Katsuta,, JP;
Shigetoshi Okamatsu, Katsuta,, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
For controlling the rotational speed of an induction motor, an inverter is provided which converts direct current to alternating current and feeds the converted current to the motor. The output voltage and frequency of the inverter is controlled by a pulse-width modulated control device. The number of pulses contained in a half cycle of the inverter output voltage are changed every time the inverter output frequency reaches one of plural predetermined reference values. The plural predetermined reference values are adjusted in accordance with the DC supply voltage and/or with the motor current.