On the Result of Observation of Earthing-Resistance
Kitamura, M.
Abstract
Under the ordinary conditions gradual changes in the contact-resistance between electrodes and adjacent parts of the soil, in which they are set, can be expected corresponding to seasonal variations in moisture and temperature. Actually many observations show that variations of earthing-resistance are chiefly due to two elements, namely, rapid change in moisture-content occurring during or after heavy rainfall and variation of the temperature in the ground near the surface.
By the method of Kohlrausch-bridge we made more systematic and long continued observations of the earthing-resistance every month in the interval from 1947 to 1950. The main result shows that it decreases as the earth-temperature increases, or as the amount of precipitation increases more than about 200 mm.
So it follows that the seasonal variation of the earthing-resistance can be considered chiefly as a result of change in the concentration, consequently conductivity, of the solution surrounding the electrodes due to the earth-temperature or impinged water.
