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:
Jun. 12, 1984
Filed:
Sep. 09, 1982
James P DeLacy, Havertown, PA (US);
Brown Boveri Electric, Inc., Rolling Meadows, IL (US);
Abstract
A reclosing system for d-c feeder circuit breakers used on transit systems is disclosed. Circuit breaker closure is prevented when the feeder circuit voltage is in a predetermined voltage range and when the feeder circuit impedance is less than a given value, which is less than the impedance which would be presented by a parked train in a deenergized portion of the transit rails. A Wheatstone bridge is inserted into the circuit during the load impedance measurement. The Wheatstone bridge circuit is compensated for positive or negative rail return voltage. The automatic reclosing scheme is locked out after two closures of the circuit breaker followed by automatic tripping within six minutes, or by twelve load impedance measurements, which are performed within three minutes and which all fail to lead to a circuit breaker closure.