The Extinction Rate Measurement of Short Gap Arcs at Low Current Ignited Between Tungsten Electrodes

摘要

On the background of (his investigation, there arc two experimental facts. One of them is that current diminishing arts do not always extinguish at a constant value of current, and another is that they are often sustained at a lower current than the generally admitted value as the minimum arc current. These two (acts are inexplicable if we accept the concept of minimum arc current literally. In order to clarify the reason of these difficulties about the minimum arc current, the author investigated the relation between the arc current and the arc sustainability, or, inversely saying, the arc extinction rate, with static tungsten electrodes, at low current range from 0.3[A] to 2.0[A], for gap length from 0.1[mm] to 0.5[mm]. The resistive circuit was used. The arc-was ignited through a breakdown of the gap. In the current range from 1.6[A] to 2.0[A], the arc was sustained longer than 45[ms]. In the current range from 0.3[A] to 1.5[A], the arc duration followed the exponential distribution, mean value being dependent on the current, from tens of microsecond to hundreds of microsecond The arc extinction rate was found to vary significantly around 1.5[A].