Abstract: A three-phase current limiter (30) for an alternating current system includes an AC magnetic circuit having at least one AC coil (35R1, 35S1, 35T1) for each phase of a 3-phase AC supply wound on a saturable ferromagnetic core and configured to subject respective AC coils for each phase to a common magnetic flux, and a DC magnetic circuit (34a, 34b) for biasing the AC magnetic circuit into saturation at normal conditions. In use the AC coils are connected in series with a load and during alternate half cycles of the AC supply at least one of the AC coils produces a magnetic field that opposes a magnetic field of the DC magnetic circuit. The AC coils (35R, 35S, 35T) for each phase are configured so that at least one of the AC coils exhibits unbalanced magnetic impedance relative to remaining ones of the AC coils for each phase.

Abstract: A current limiting device (30, 40, 50, 60) comprising for each phase of an AC supply a closed magnetic core (31) of reduced volume and mass having first and second pairs of opposing limbs (32a, 32b; 33a, 33b), and at least one AC coil (35a, 35b) enclosing opposing limbs (33a, 33b) of the magnetic core (31) and adapted for series connection with a load. A superconducting DC bias coil (34) encloses a limb) (32a, 32b) of the magnetic core (31) for saturating each of the opposing limbs (33a, 33b) in opposite directions by the bias coil (34). Under fault conditions, the AC flux in at least one limb counteracts the DC bias flux, bringing the limb out of saturation. Preferably, current is reduced in the DC bias coils thus bringing both opposing limbs of the core out of saturation.

Abstract: A current limiting device (30, 40, 50, 60) comprising for each phase of an AC supply a closed magnetic core (31) of reduced volume and mass having first and second pairs of opposing limbs (32a, 32b; 33a, 33b), and at least one AC coil (35a, 35b) enclosing opposing limbs (33a, 33b) of the magnetic core (31) and adapted for series connection with a load. A non-superconducting DC bias coil (34) typically formed of copper encloses a limb (32a, 32b) of the magnetic core (31) for saturating each of the opposing limbs (33a, 33b) in opposite directions by the bias coil (34). Under fault conditions, the AC flux in at least one limb counteracts the DC bias flux, bringing the limb out of saturation. Preferably, current is reduced in the DC bias coils thus bringing both opposing limbs of the core out of saturation.

Abstract: A current limiting device (30, 40, 50, 60) comprising for each phase of an AC supply a closed magnetic core (31) of reduced volume and mass having first and second pairs of opposing limbs (32a, 32b; 33a, 33b), and at least one AC coil (35a, 35b) enclosing opposing limbs (33a, 33b) of the magnetic core (31) and adapted for series connection with a load. A superconducting DC bias coil (34) encloses a limb) (32a, 32b) of the magnetic core (31) for saturating each of the opposing limbs (33a, 33b) in opposite directions by the bias coil (34). Under fault conditions, the AC flux in at least one limb counteracts the DC bias flux, bringing the limb out of saturation. Preferably, current is reduced in the DC bias coils thus bringing both opposing limbs of the core out of saturation.

Abstract: A superconducting coil having form of pancake or double pancake wound of non-insulated superconducting wire (tape) with insulating layer between adjacent turns composed of epoxy resin filled with ceramic powder of high thermal conductivity. A superconducting coil composed of several pancakes and/or double pancakes and includes layers of said epoxy with or without additional spacers between adjacent pancakes. Pancakes or double pancakes as well as coils, consisting of several pancakes and/or double pancakes that have a solenoid form or racetrack or saddle forms.