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. 25, 1989
Filed:
Dec. 09, 1987
Applicant:
Inventors:
Ryoichi Shiobara, Hitachi, JP;
Masao Ohi, Mito, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01R / ; H02P / ; H02K / ;
U.S. Cl.
CPC ...
3241 / ; 324546 ; 324547 ; 324 55 ; 318490 ; 318696 ; 322 99 ;
Abstract
A fault diagnosis system for a rotor winding of rotary electric machines is disclosed, in which the rotor winding of rotary field type is excited in DC fashion by an excitation circuit, on which an AC voltage is superposed, the impedance of the rotor winding is calculated from the current and voltage of the AC portion flowing in the rotor winding, and the resulting impedance is compared with a reference impedance thereby to decide a fault, if any, of the rotor winding, thus making possible accurate diagnosis of a rotary electric machine even while it is running.