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:
Jun. 29, 1993
Filed:
May. 20, 1991
Applicant:
Inventor:
Michael Kruger, Edingen-Neckarhausen, DE;
Assignee:
Heidelberger Druckmaschinen AG, Heidelberg, DE;
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02P / ;
U.S. Cl.
CPC ...
388809 ; 388814 ; 388815 ; 3889075 ;
Abstract
A method for measuring the rotary speed of a direct-current motor having a rotor and at least a shunt-wound field winding, wherein the field current includes an ac-component caused by mass-inhomogeneities in the rotor, including the steps of: frequency analyzing with a frequency analyzer the ac-component to form a frequency spectrum; selecting with a computing device a part of the frequency spectrum related only to the rotary speed; and determining from the selected part of the frequency spectrum the rotary speed of the motor.