Clamp Earth Resistance Tester is widely used in earth resistance measurement of electric power, telecommunication, meteorology, oil field, construction and industrial electrical equipment. So what is the principle of ground resistance tester?

Clamp ground resistance tester measurement principle:

1. Principle of Resistance Measurement

The basic principle of ETCR series clamp earth resistance tester to measure earth resistance is to measure loop resistance. See below. The jaw part of the clamp meter consists of a voltage coil and a current coil. The voltage coil provides the excitation signal and induces a potential E on the loop under test. Under the action of the potential E, a current I will be generated in the circuit under test. The clamp meter measures E and I, and the measured resistance R can be obtained by the following formula.

2. Current measurement principle

The basic principle of measuring current with a clamp-on grounding resistance tester is the same as that of a current transformer. See below. The AC current I of the measured wire generates an induced current I1 through the current magnetic ring and the current coil of the jaw, and the clamp meter measures I1, and the measured current I can be obtained by the following formula.

Among them: n is the conversion ratio of the secondary side and the primary side coil.