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Passive fault current limiting device

United States Patent

5,892,644
April 6, 1999
View the Complete Patent at the US Patent & Trademark Office
Argonne National Laboratory - Visit the Technology Development and Commercialization Website
A passive current limiting device and isolator is particularly adapted for use at high power levels for limiting excessive currents in a circuit in a fault condition such as an electrical short. The current limiting device comprises a magnetic core wound with two magnetically opposed, parallel connected coils of copper, a high temperature superconductor or other electrically conducting material, and a fault element connected in series with one of the coils. Under normal operating conditions, the magnetic flux density produced by the two coils cancel each other. Under a fault condition, the fault element is triggered to cause an imbalance in the magnetic flux density between the two coils which results in an increase in the impedance in the coils. While the fault element may be a separate current limiter, switch, fuse, bimetal strip or the like, it preferably is a superconductor current limiter conducting one-half of the current load compared to the same limiter wired to carry the total current of the circuit. The major voltage during a fault condition is in the coils wound on the common core in a preferred embodiment.
Evans; Daniel J. (Wheeling, IL), Cha; Yung S. (Darien, IL)
The University of Chicago (Chicago, IL)
08/ 975,431
November 20, 1997
CONTRACTUAL ORIGIN OF THE INVENTION The United States Government has rights in this invention pursuant to Contract No. W-31-109-ENG-38 between the U.S. Department of Energy and The University of Chicago representing Argonne National Laboratory.