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:
Mar. 30, 2004
Filed:
Feb. 19, 2002
Gary Hoffman, Randolph, NJ (US);
Other;
Abstract
The load current drawn from a power transformer is sensed to determine if and when the load current exceeds a predetermined threshold. The length of time the load current exceeds the threshold is also sensed. By monitoring the excess current flow and the length of time for which it flows, it is possible to anticipate a rise in the winding temperature of the power transformer and to initiate cooling before the windings have reached a critical temperature, as a function of the ambient temperature and/or the temperature of the transformer. Thus, systems embodying the invention include circuitry for sensing the current drawn from and/or by a transformer, determining when the current exceeds a predetermined value and timing circuits for sensing the length of time for which the excess current flows. The timing circuits are needed, in part, to differentiate between a transitory overload condition and a static, continuous, overload condition.