The circuit resistance tester under UHV power can help many power workers conduct various power tests more conveniently.

The circuit resistance tester is designed by combining digital circuit technology and switching power supply technology. The circuit resistance tester is suitable for measuring the contact resistance and circuit resistance of switch control equipment. The test current is DC 100A recommended by the national standard. The circuit resistance and contact resistance can be directly measured and digitally displayed at 100A current.

Why does the regulation require the use of at least 100A DC current to detect switch circuit resistance?

1. Firstly, because there is an oxide film between the switch contacts, if a smaller current is used for detection, the test results will generally be much larger due to the influence of the oxide film, but the oxide film can be broken down under high current. In theory, as long as the test current does not exceed the rated current, the larger the better. However, when formulating regulations, considering the production level of relevant instruments in China at that time, it is stipulated that the current cannot be less than 100A.

2. Secondly, due to the low contact resistance of circuit breakers, only high current detection can ensure a certain level of accuracy, and their anti-interference ability is also stronger.