Measurement of Arc Resistance by Chemical Flame

Abstract

Concerning arc resistance of electric insulating materials, development of a reasonable and simple method of testing was recommended for consideration. Taking the deterioration in the low voltage high current arc to be due to the deterioration of its energy source, which was thought to be the low voltage high current arc itself, the bunsen burner was used for the thermal energy source, considering that the equivalent energy source was not to be necessarily confined to electric thermal energy source, but the use of simple energy source such as chemical flame might as efficiently substitute. The test insulator was held horizontally at a constant distance from the nozzle of the burner, and was subjected to deterioration. Then the temperature of the part of the flame which was in contact with the insulator was fixed at 1000°C and at the distance of 50mm. from the nozzle in this condition. The length of the flame was kept at about 70mm. constantly. And then the degree of deterioration was examined by measuring the post-test surface resistance. The two surface resistances, pre-test and post-test, were compared, and the ratio of the lowering determined the character of the deterioration and of the arc resistance.The above mentioned subject was also studied from the point of arc resistance test by low voltage high current. The comparative studies were carried out smoothly. The measurement agreed fairly with the results of various other arc resistance tests by low voltage high current. The present test has thus proved a practical method.