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Principle and Application of Loop Resistance Test Instrument

Time: 2022-04-06 Author: 铧正 Click: 919 Time

Principle and Application of Loop Resistance Test Instrument


With the rapid development of my country's economy, the demand for electric power is increasing day by day, and the contribution of the development of the electric power industry to the society is becoming more and more prominent. Loop resistance is an important parameter indicating whether the conductive loop connection is good or not, and its value affects the current-carrying capacity of normal operation and the ability to cut off short-circuit current. In the process of preventive test and handover test, electrical workers need to accurately measure the loop resistance value of power transformers, switches, circuit breakers and other high-current equipment in the power system. The loop resistance value mainly depends on the loop resistance between the moving and static contacts. Therefore, equipment such as power transformers and switch circuit breakers have become important parameters for the safe operation of the power grid.


What is the main way to use this circuit resistance tester when electric workers do experiments? how to use? Today I will give you a detailed introduction below.


Because the loop resistance tester works under the condition of high current, in order to eliminate the lead resistance and improve the measurement accuracy, the four-wire connection measurement method is adopted. At the same time, in order to avoid overheating, the current duration should be short and the current connection should be firm. The detection points are selected uniformly according to the specification requirements. When the loop resistance tester outputs current, the output value of the loop resistance tester is directly compared with the digital display reading of the high-power DC active resistance, which can greatly improve the measurement accuracy.


When the loop resistance tester is measuring, the high-frequency switching power supply system outputs a current of 100A or more, which is applied between the two terminal buttons of the measured resistance, and the circuit information is collected through a sampling module and the current flows through the measured resistance. The analog analysis signal of the voltage drop generated by the resistance is amplified by the preamplifier, and the analog input signal model is converted into a digital economic signal by the A/D converter, and then the data technology is filtered, calculated and processed by the microprocessor. , According to the principle that the fault current of the whole circuit is equal everywhere, by studying Ohm's law R=U/I, the DC resistance value of the measured object is calculated from the ratio of the voltage drop U across the load and the current I in the loop .


The circuit resistance tester adopts the high reliability of high-power integrated circuits, adopts DC constant source, preamplifier, A/D converter, indicator device, etc., is ms, micro-range low-value resistance meter, simple operation, can be used as the key Measure circuit resistance, wire resistance, coil resistance, etc. The test circuit can automatically stabilize the current to ensure stable and reliable test data.

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Loop Resistance Test Instrument



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