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:
Jan. 03, 1984
Filed:
Jan. 07, 1982
Thomas R Payne, Louisville, KY (US);
Robert V Chou, Prospect, KY (US);
General Electric Company, Louisville, KY (US);
Abstract
A protective control arrangement for heating units of the type comprising the concentric assembly of a resistance heating element embedded in an insulating material and enclosed within a metallic sheath for limiting the propagation of a rupture in the sheath resulting from an arc at a discontinuity in the heating element along a substantial portion of the length of the sheath. The control arrangement of the illustrative embodiment includes a power control triac operatively connected to the heating element for selectively coupling the heating element to an external power supply. A preprogrammed microprocessor operatively connected to the gate terminal of triac is effective to periodically interrupt power to the heating element by opening the switch means for interrupt periods of predetermined duration. The time between successive ones of these interrupt periods is determined such that extinction of any arc which may develop at a discontinuity in the heating element occurs before any resultant separation can propagate along a substantial portion of the sheath; and the duration of each of these interrupt periods is at least approximately equal to the nominal recovery time for the insulating material required to allow the insulating material to return from its relatively low resistance molten and plasma state to its relatively high resistance state. By periodically interrupting energization of the heating unit in this manner, any arc which occurs is extinguished by the next occurring interrupt period.