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. 22, 1988
Filed:
Apr. 13, 1987
Francois Lindeperg, Sassenage, FR;
Merlin Gerin, , FR;
Abstract
An instantaneous solid-state trip device has two threshold values providing an upper and a lower tripping threshold. A current increase rate detector determines, when a short-circuit occurs, the prospective peak current value and, if the peak value corresponding to the electrodynamic withstand of the circuit breaker is liable to be exceeded, causes a change of threshold to bring about tripping, as soon as the lower threshold is exceeded. This high-speed tripping favours short-circuit current limiting. When a short-circuit of a lesser importance occurs, the current variation is lower and the instantaneous trip release only trips when the upper threshold is exceeded. In most cases, this upper threshold is not reached and tripping selectivity can be easily achieved in the usual way. A break in the circuit connecting the sensor to the trip unit also causes the circuit breaker to trip.