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:
Mar. 12, 1985
Filed:
Dec. 10, 1982
Applicant:
Inventors:
Kinzo Wada, Yokohama, JP;
Ken Enami, Kawasaki, JP;
Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H02H / ;
U.S. Cl.
CPC ...
361 23 ; 361 28 ; 361240 ; 361242 ; 318434 ; 318461 ; 318476 ;
Abstract
A protective circuit for an electric motor comprises a frequency signal generating circuit for generating a frequency signal in accordance with the rotational speed of the motor, a switching circuit switched over to either permit or cut off supply of current to the motor, and a detecting circuit for detecting that the period of the generated frequency signal has become larger than a predetermined period due to a decrease in the rotational speed of the motor, and cutting off the supply of current to the motor by the switching circuit.