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. 13, 1980
Filed:
Jul. 31, 1978
Applicant:
Inventor:
Donald E Lee, Abington, PA (US);
Assignee:
Other;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H02H / ;
U.S. Cl.
CPC ...
361 42 ; 324 52 ; 328132 ; 361 87 ;
Abstract
Disclosed is a ground fault detection system utilizing a distributed array of current rate of rise sensors located at and coupled to the various power substations of an underground trolley system. Threshold detectors and logic circuits measure and compare the rate of rise of current at the various substations with preselected threshold values to distinguish ground faults from normal load transients due primarily to locomotive start-up.