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:
Oct. 03, 2000
Filed:
Sep. 16, 1999
David H Halvorson, Cedar Rapids, IA (US);
Westinghouse Air Brake Technologies Corporation, Wilmerding, PA (US);
Abstract
A method and apparatus detects leakage current on a two wire power line and, in particular, provides a way to prevent hazardous electrical shocks to personnel on ECP equipped railroad trains. Two resistors of equal value are respectively connected in series to the two wires of the power line. A sensing resistor is connected in series with a junction of first two resistors, and a low voltage power source is connected between the sensing resistor and earth ground. A sensor is connected across the sensing resistor to detect a leakage current. The sensor is capable of detecting either positive or negative leakage currents. An output of the sensor is supplied to a controller which controls a high voltage power source connected across the two wires of the power line to be either in an OFF state or enabled to be in an ON state, depending on whether a leakage current is sensed by the sensor.