Repetitive over-current characteristics of the joints between the YBCO coated conductor

In recent years, the YBCO coated conductor (CC) has been developed as a suitable material for power apparatuses. To fabricate a superconducting apparatus of a large capacity, the joint between the superconducting tapes are inevitable because of the need to have a long length conductor. Consequently, the joint characteristic is very important for the efficiency of the superconducting part in the apparatuses. Besides, maintaining the characteristic of the joint between the superconducting tapes even after repetitive over-current is also important for stability of power apparatuses. Therefore the joints between CC tapes were developed in differing joint length and the characteristics of the joints were compared. In this paper, we present the experimental results of several over-current experiments with the jointed CC tapes. The results of the over-current experiments and the trend of the joint characteristics are compared in point of stability of the joints. Resistance and critical current of the joints were measured from the V - I curve before and after several over-current experiments for observation of the trend of the joint characteristics. This study of repetitive over-current characteristics of the joints may be useful to the development of superconducting apparatuses in forms of magnets.