| 摘要 |
PURPOSE:To realize interruption without generating a voltage drop across both ends of a fuse element even if a large current flows in it and also without generating arcs even if a direct current is used, by keeping the fuse element, made of a superconductive material, at a superconduction.normal-conduction transitional temperature or below. CONSTITUTION:A fuse element 4 is normally cooled at a transition temperature or below by a coolant. A resistance of the fuse element 4 on this state is zero, and also a voltage drop across connection terminals 21 and 22 is zero. When a current flowing in the fuse element 4 is made to be in excess of a critical current value Ic by overload and short-circuit, a superconductive state of the fuse element 4 is broken to perform its transition to a normal-conductive state. This transition allows the resistance of the fuse element 4 to increase so that a circuit current is decreased smoothly. Hence, even in the case of direct-current interruption, smooth interrupting operation is realized without generating arcs. |
