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:
Apr. 26, 1994
Filed:
Aug. 25, 1992
Applicant:
Inventor:
Youji Nakamura, Fukuoka, JP;
Assignee:
Mitsubishi Denki K.K., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02H / ;
U.S. Cl.
CPC ...
318806 ; 318799 ; 318461 ; 361 23 ; 361 88 ;
Abstract
A protection control circuit for a variable speed hoisting device driven by an induction motor includes, in addition to the inverter unit 1 for supplying power to the induction motor 2 and relays, a rotary encoder 16 and an abnormality detector 15. When the rotary encoder 16 does not generate output in spite of the fact that an operation instruction is input, the abnormality detector 15 opens the normally closed contact 15b2 to stop the inverter unit 1 and turns on the invertor abnormality display lamp 15d1 and rotation detector abnormality display lamp 15d2.