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. 06, 1982
Filed:
Apr. 23, 1980
Applicant:
Inventors:
Isao Fukushima, Katsuta, JP;
Hideo Nishijima, Katsuta, JP;
Kenji Satoh, Yokohama, JP;
Tunehiko Teshima, Katsuta, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H02D / ;
U.S. Cl.
CPC ...
318328 ; 318341 ; 318327 ;
Abstract
When the number of revolutions of a motor, or a motor speed is reduced half, a gain of a frequency-voltage converter is doubled. By taking advantage of this fact, a gain of an error signal amplifier disposed at the poststage of the frequency-voltage converter is automatically changed to be half interlocking with a switching operation for switching the number of the motor revolutions to the half.