UHV Power's loop resistance tester can help many power workers to carry out various power tests more conveniently.

The loop resistance tester is made using digital circuit technology and switching circuit technology. It is a special device for measuring the contact resistance and loop resistance of switching control equipment. The circuit resistance of a circuit breaker mainly depends on the contact resistance of the dynamic and static contacts. The presence of contact resistance increases the loss of the conductor when energized and increases the temperature of the contact point. Its value directly affects the current-carrying capacity during normal operation. Capacity, to a certain extent, affects the ability to cut off short-circuit current, and is also an important data reflecting the quality of installation and maintenance work.

There are three main test methods for loop resistance testers, and the specific operations are as follows:

1. Bridge method: When measuring the resistance of the conductive circuit of the circuit breaker with a double-arm bridge, it is difficult to eliminate the oxide film with large resistance due to the weak current passing through the measurement loop, and the measured resistance value is too large. The current is small, and it is difficult for the contact points of the contacts to shrink, that is, the shrinkage resistance cannot be measured.

2. Voltage drop method: when direct current is applied to the circuit under test, a voltage drop will be generated on the contact resistance of the circuit, and the current and voltage value through the circuit will be measured to obtain the contact resistance. is calculated. 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 principle of voltage drop, but the measurement and calculation are all processed by the single-chip microcomputer, which greatly reduces the workload.