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:
May. 28, 1996
Filed:
Nov. 14, 1994
Applicant:
Inventors:
R Wendell Goodwin, Dunwoody, GA (US);
Charles W Roberts, Roswell, GA (US);
Assignee:
Schlumberger Industries, Inc., Norcross, GA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01F / ; H01F / ;
U.S. Cl.
CPC ...
336178 ; 336175 ; 336184 ; 336212 ;
Abstract
An air-coupled current transformer is provided with a primary current conductor and two secondary coils connected such that the emf induced in each coil by an external disturbing magnetic flux is subtractive, whereas the emf induced by the current in the primary is additive. Two ferromagnetic core pieces enhance the rejection of the emf induced by the disturbing flux. Ceramic spacers are inserted into air gaps between the core pieces for maintaining the gaps fixed to keep the scale factor of the transformer independent of temperature.