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. 11, 1991
Filed:
Aug. 23, 1989
Paul Baits, Rockford, IL (US);
Sundstrand Corporation, Rockford, IL (US);
Abstract
The problem of detecting low frequency faults is solved in a VSCF control system which is operated in a start mode to start an engine (18) using a brushless synchronous generator operating as a motor (12). The motor (12) receives power through a feeder (52) from a converter (36) which is coupled through an additional feeder (44) to a source (42) of AC power. During normal, non-fault conditions, the sum of the input currents to the converter (36) and the sum of the output currents from the converter (36) must each be zero. When a fault condition exists, then one or both of these currents will be non-zero, depending upon the location of the fault. A single current sensor (56) is used to sense feeder faults by positioning the sensor to read the current through the converter input feeder (44). As long as no feeder to ground fault condition exists, then the current sensor (44) senses zero current. If a non-zero current is sensed, then it is assumed that a fault condition exists.