Grounding conductivity resistance tester referred to as the conductivity tester, is the application of the principle of high-current testing of electrical equipment shell and the safety of the ground conductivity of the instrument to check the grounding quality of the equipment, is used for household electrical appliances, electric heating appliances, medical equipment and measurement, control and laboratory electrical equipment, etc., by the AC power grid power supply of electrical equipment, the accessible metal casing and the safety of the ground between the measurement of conductivity resistance. Measurement of conduction resistance between the accessible metal casing of electrical equipment powered by the AC power grid and the safety ground.
Ground on-resistance tester is through the output of AC constant current, applied to the test body of the accessible metal shell and the safety of the ground between, and measure the constant current flow through the body of the voltage drop, and then through the voltage value and the current value of the ratio of the body of the ground on-resistance value of the test, or a direct display, direct indication of the body of the test of the ground resistance value of the ground on-resistance. Its test current for 1A, 10A, 25A, and 30A, generally not less than 25A. ground on-resistance tester can directly output resistance, measurement of current, and provide AC digital voltmeter to measure the no-load voltage of the current source, but also for the calibration of the basic error of the resistance, the calibration of the alarm preset error, the calibration of the error of the output test current and stability test, the measurement of the current source of the no-load voltage.
Grounding resistance tester is a common instrument for inspection and measurement of resistance to ground, but also electrical safety inspection and acceptance of the completion of the project according to the ground indispensable tool, in recent years, due to the rapid development of computer technology, so according to the grounding resistance tester is also infiltrated with a large number of microprocessor technology, its measurement function, content and accuracy of the general instrument can not be compared. At present, the advanced resistance tester can meet all the requirements of the ground measurement, a powerful ground resistance tester are controlled by microprocessor controller, can automatically detect the connection status of each interface and ground network interference voltage.
The main function of the grounding resistance tester is to accurately measure the large grounding network grounding impedance, grounding resistance, grounding reactance; accurately measure the large grounding network field surface potential gradient; accurately measure the large grounding network contact potential difference, contact voltage, step potential difference, step voltage; accurately measure the transfer potential of the large grounding network; measurement of the grounding lead wire conductivity resistance; measurement of soil resistivity.
Earth resistance measurement using square wave excitation test, 4 test frequency (94Hz, 105Hz, 111Hz, 128Hz), can be manually selected, so as to avoid interference sources for grounding measurement. Tested open circuit voltage: maximum 50V; short circuit current <20mA. can remove the residual resistance of the test line, over-limit or incorrect test conditions warning function, panel calibration technology to ensure that it reaches the desired accuracy and performance.