Characteristics of Arc Voltage and Metallic Vapor Pressure in the Enclosed Capillary

Abstract

It is interested in the current limiting fuses that generate high arc voltage and show remarkable current limiting effect. We experimentally investigate the mechanism of high arc voltage generation in the insulated capillary of inorganic material.
The insulated capillary with small inner diameter is made of Pyrex glass. The test sample is consisted of the insulated capillary, a slender copper wire fuse element strained along the center axis in the insulated capillary and the fuse element terminals. The test sample is put in the enclosed vessel that could withstand high pressure. Arc current, arc voltage and pressure generated during the experimental period are observed. It is shown that the change of arc voltage waveform depends on dimension of the insulated capillary, arc current density and pressure in the vessel.
The maximum pressure closely depends on the evaporated fuse element material during arc period, is reached after arc current zero due to a narrow compressible air channel. It is clear that the maximum of arc voltage is dominated by evaporated fuse element vapor density.