Electrical resistors – Resistance value responsive to a condition – Magnetic field or compass
Patent
1996-07-30
1998-10-27
Wong, Peter S.
Electrical resistors
Resistance value responsive to a condition
Magnetic field or compass
505881, 361141, H01L 4300, H01L 4312, H01H 4700
Patent
active
058282912
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is based on a current limiter device.
2. Discussion of Background
Reference is made to U.S. Pat. No. 4,961,066, in which a current limiter is disclosed, for fast current limitation in the event of short circuits. The current limiter can include a support insulator which is rod shaped, tubular or a planar layer structure, in each case consisting of a support insulator. A thin superconducting layer is applied extensively thereon and a normal conductor resistive layer is applied extensively on the latter. The last two layers can be repeated one after the other. In this case, the resistance of the non-superconducting resistor is less than that of the superconductor in the normal conducting state. Disadvantages are large power losses in AC operation as well as relatively long conductors.
In regard to the relevant prior art, reference is also made to EP-A1-0,406,636. The latter provides, for limiting overcurrents in an electrical line of an AC circuit, for example as a result of a short circuit, a current limiter in which an induction coil is connected in a branch in parallel with a high temperature superconductor. The superconductor is arranged inside the induction coil and is also connected in parallel with a non-superconducting shunt resistor.
SUMMARY OF THE INVENTION
Accordingly, one object of the invention is to provide a further development of a current limiter device of the type mentioned at the outset in such a way that it is suitable for the resistive limitation of both direct and alternating currents. The intention is to limit an overcurrent, in the event of a short circuit, to a predeterminable multiple of the rated current.
An advantage of the invention consists in that the current limiter device is simple and compact. The superconducting part of the current limiter is of modular design, that is to say that the superconductor is subdivided into units which, should the need arise, can be removed and replaced separately.
According to an advantageous configuration of the invention, the compound conductors, consisting of superconductors and normal conductors, used in the current limiter can be arranged with low inductance. By virtue of a suitable conductor arrangement, AC losses which occur in the case of AC applications can be greatly reduced.
The current limiter device can also be used as an active switching element by introducing it into an external magnetic field. In this case, use is made of the fact that the critical current is very greatly reduced in magnetic fields. By switching on the external magnetic field, it is therefore possible to reduce the current in the superconductor to a fraction of the rated current.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
FIG. 1 shows, in cross section, a modular arrangement of current limiters in a magnetic field coil,
FIG. 2 shows, in cross section, a current limiter according to FIG. 1,
FIG. 3 shows, in a cross section, a superconductor of the current limiter according to FIG. 2, with a meandering conductor track,
FIG. 4 shows signal diagrams of AC losses with current limiters, and
FIGS. 5-8 show current limiters with different layer sequences.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, FIG. 1 shows 4 current limiters or current limiter modules (5), which are arranged parallel to one another in a cryostat (7) filled with liquid nitrogen, are electrically connected in series and are connected to an electrical line (6). During operation, a current (I) which, in the event of an overcurrent, for example as a result of a short circuit, is intended to be limited by the current limiter modules (5)
REFERENCES:
patent: 3335295 (1967-08-01), Klinkhamer
patent: 4961066 (1990-10-01), Bergsjo et al.
patent: 4970483 (1990-11-01), Wicker et al.
patent: 4994932 (1991-02-01), Okamoto et al.
patent: 5153804 (1992-10-01), Pham et al.
patent: 5235309 (1993-08-01), Preisler et al.
patent: 5250508 (1993-10-01), Pham
patent: 5310705 (1994-05-01), Mitlitsky et al.
patent: 5387890 (1995-02-01), Estop et al.
"Superconducting Fault Current Limiter",EPRI EL-329 (Research Project 328), Final Report, Dec. 1976, Argonne National Library, Argonne, Illinois.
K.J. Best et al., "Anisotrophy of Optimized and Not Optimized Technical NbTi Superconductors", IEEE Transactions on Magnetics vol. Mag-15, No. 1, Jan. 1979.
"Supraleitung", 4., uberarbeitete und erganzte Auflage, Werner Buckel, p. 236.
"Low Resistance Ohmic Contact for the Oxide Superconductor EuBa.sub.2 Cu.sub.3 O.sub.y ", Sugimoto et al., Japanese Journal of Applied Physics, vol. 27, No. 5, May 1988, pp. L864-L866.
Baumann Thomas
Paul Willi
Rhyner Jakob
ABB Research Ltd.
Vu Bao Q.
Wong Peter S.
LandOfFree
Multiple compound conductor current-limiting device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Multiple compound conductor current-limiting device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multiple compound conductor current-limiting device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1616676