The choice of voltage level of DC resistance tester mainly depends on the size and nature of the resistance to be measured. For example, 3-5A DC resistance testers are generally used for 10kV voltage levels; 35kV voltage level is generally selected 10A DC resistance tester. 20A DC resistance tester is usually used for 110kV voltage level; The 40A DC resistance tester is mainly used for the 220kV voltage level. In the selection, it is necessary to pay attention to the selection of the current can not be too large or too small, because the current is too large may cause the transformer temperature to rise, resulting in inaccurate resistance testing; However, if the current is too small, the error of the test result may increase.
In addition, the choice of DC resistance tester model is also very important. For example, some models of DC resistance testers may have a measuring range of 1μΩ to 20 kΩ, 7 ranges available. Other models may have a measuring range of 1μΩ to 2MΩ, with 9 ranges to choose from. Therefore, when choosing a DC resistance tester, the user needs to choose the appropriate model and measurement range according to the actual demand and the size of the resistance to be measured.