抄録
A transition duration at the steady arc occurrence and termination caused by interrupting a current is measured. In consideration of the fast transients and high frequency discharge phenomena due to interrupting the current, a transmission line system was introduced. It consists of a coaxial switch, coaxial cables as transmission lines on the right and left sides of the switch, and termination resistors. The material of the inner conductor of the coaxial switch for interruption of the current is silver and copper. The resistors were designed to match the characteristic impedance of the cables. A semi-rigid cable as a coaxial cable and a coaxial attenuator (DC∼8.5GHz) as the termination resistor were used on the right side of the switch for measurement of transition duration. When the current is interrupted by the switch, the transient waveform of output of the attenuator is measured by an oscilloscope (DC∼4.5GHz). Regardless of the materials of the center conductor of the switch, the transition duration at the arc occurrence and termination caused by interrupting low current (0.5-1.0A) is 0.2∼0.4 ns and 1.28∼2.08 ns, respectively, and does not depend on the material of the inner conductor of the switch and current value. The transition duration at the arc occurrence is very rapid.
