The loop resistance tester, also known as the contact resistance tester, is mainly used to test the contact resistance of the static and dynamic contacts of the high-voltage circuit breaker. The circuit resistance of the circuit breaker mainly depends on the contact resistance of the static and dynamic contacts. The presence of contact resistance increases the loss of the conductor when it is energized, and increases the temperature at the contact. The value of its value directly affects the current-carrying capacity during normal operation. To a certain extent, it affects the ability of short-circuit current to cut off, and it is also an important data reflecting the quality of installation and maintenance work. At present, there are mainly three test methods for loop resistance testers, and the specific operations are as follows:

Huaying loop resistance tester

1. Electric bridge method: When the double-arm electric bridge is used to measure the resistance of the circuit breaker's conductive circuit, the measurement circuit passes a weak current. It is difficult to eliminate the oxide film with large resistance, and the measured resistance value is too large, and because the current is small. It is difficult to form shrinkage at the contact point of its contact, that is, the shrinkage resistance cannot be measured.

2. Voltage drop method: When a direct current is applied to the circuit under test, a voltage drop will be generated on the contact resistance of the circuit. Measure the current value and voltage value through the loop, and calculate the contact resistance. The test process is cumbersome, and the measurement results are calculated manually, and there are certain errors.

3. Micro-ohmmeter method (loop resistance tester): The principle is the voltage drop principle. It's just that the measurement and calculation are all processed by a single-chip microcomputer, which greatly reduces the workload.