S-N transitions of QMG current limiting elements with metal coat

To estimate the feasibility of resistive type FCL (fault current limiter) consisting of QMG (melt processed YBa/sub 2/Cu/sub 3/O/sub 7-x//Y/sub 2/BaCuO/sub 5/ composite bulk superconductor), S-N transitions of various metal-coated samples made from large bulk QMG were studied at 77.3 K and 87.3 K (boiling point of argon) using single rectangular pulse current. It was found that the metal coating dramatically improves the endurance of element against the current flow after S-N transition and that optimization of the endurance and resistance should be required to realize QMG-FCL.