The Predominating Influence of Moisture and Electrolytic Material Upon Textiles as Insulators

Attention is called to the practical importance of water in all insulators and especially to the extreme electrical sensitivity to moisture of textiles as a class. Significant amounts of electrolytic impurities occur in many insulators. In textiles in the presence of moisture such impurities are responsible for very conspicuous features of electrical behavior. Data are given showing their effect on the insulation resistance of cotton and silk. The insulation resistance of textile fibers in moist air rises greatly with duration of d-c. voltage, accompanied by many evidences of electrolysis of aqueous solutions of impurities in the textile. The instantaneous insulation resistance of fibers decreases with increase of the measuring voltage as previously shown by Evershed. However, this fact does not necessarily support his idea of kinetic redistribution of water in textiles, as this behavior is also compatible with the nature of electrolytic conducttion. Electrolytic impurities may be washed out of textiles and substantial practical improvements effected thereby. The increase of resistance is of the order of 50 times. Fibers are classified according to their electrical behavior in a manner which is also in harmony with their chemistry as follows; (1) Animal fibers. These are of protein nature and are characterized by high moisture content at ordinary humidities and by great electrical sensitivity to further increments of moisture, yet possess excellent insulating properties under usual atmospheric conditions. (2) Vegetable fibers.