Construction and Operation of Earth Resistance Tester

Construction and Operation of Earth Resistance Tester Points : Construction and Operation of Earth Resistance Tester The earth tester is a special type of megger which sends a.c. through earth and d.c. through measuring instrument. Fig shows the arrangement of an earth tester. In addition it has a rectifier and rotating current reverser. It has got four terminals P₁, C₁, P₂ and C outside. Two terminals P₁ and C₁are shorted to form a common point, which is connected to the earth electrode under test. The other two terminals C₂ and P₂ are connected to the auxiliary electrodes “A” and “B” respectively. The value of earth resistance is indicated by the instrument directly when its handle is turned at uniform speed.