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.

Date of Patent:
Dec. 23, 2008

Filed:

Nov. 10, 2003
Applicants:

Jonathan Keith Jackson, Bangor, GB;

Andrew Williams, Conwy, GB;

Inventors:

Jonathan Keith Jackson, Bangor, GB;

Andrew Williams, Conwy, GB;

Assignee:
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02H 3/00 (2006.01);
U.S. Cl.
CPC ...
Abstract

A residual current device (RCD) protects a circuit by tripping in response to an imbalance signal representative of residual current imbalance in the circuit. The RCD trips the circuit when the imbalance signal exceeds a predetermined threshold rating. The RCD includes a sense coil for generating the imbalance signal and a test coil for introducing a simulation residual current imbalance into the device so as to increase the imbalance signal. A processor monitors the imbalance signal and determines the simulation residual current imbalance required to increase the imbalance signal to a level that corresponds to the predetermined threshold rating so that the sense coil senses the sum of any residual current imbalance in the circuit being protected and the simulation residual current imbalance in order to test operation of the RCD against the predetermined threshold rating.


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