PROBLEM TO BE SOLVED: To provide a current equalizer circuit made of a superconductor that can reduce inconvenience relating to the current-carrying capacity and the a.c. loss without deteriorating inherent superconductivity.
SOLUTION: Superconductors 1 and 2 having different inductances are connected with each other parallel to an a.c. power supply 3 producing a current I0. Since the inductances are different from each other, magnetic fluxes produced in an iron core 4 with the generated currents I1 and I2 become different from each other, thereby not compensating the magnetic fluxes and producing the actual magnetic flux instead. The produced magnetic flux interlinks in a coil 3 to produce a voltage on both ends of an interphase reactor 5. A circulation current I3 starts flowing in a closed circuit comprising the superconductors 1 and 2 and coil 3 by the voltage. As a result, the current I3 is added to the current I1 of the superconductor 1, and it is subtracted from the current I2 of the superconductor 2, and finally, all currents flowing in the superconductors 1 and 2 become I0/2.