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:
May. 31, 1977
Filed:
Dec. 19, 1975
Applicant:
Inventors:
Hugh J Tyler, Santa Ana, CA (US);
Dennis E Newell, El Segundo, CA (US);
Assignee:
Robertshaw Controls Company, Richmond, VA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H02H / ;
U.S. Cl.
CPC ...
361 33 ; 307236 ; 307350 ; 361 92 ;
Abstract
In a protection circuit for a device such as a motor, the unused half or a dedicated half of an AC signal on the secondary of an isolation transformer is sensed to disconnect the AC line from the device if the line voltage is abnormal, such as being too low. Conveniently the protection circuit is employed in a complete motor protection system which may include a thermal protection circuit, a low oil pressure protection circuit, and/or a time delay circuit to prevent start-up too soon after shut-down.