The user can choose the suitable high-voltage insulation resistance tester according to the characteristics of the test product and the requirements of the test regulations. The principle of selection is mainly the test voltage level of the insulation resistance tester, the output short-circuit current and the range of the range meet the requirements of the regulations, and the higher the accuracy of dynamic measurement And anti-site interference ability, safe and convenient to use, better cost performance and so on. According to different test objects and requirements, the insulation resistance tester can be roughly divided into three types: universal, dominant, and special. According to the electrical equipment prevention and handover test regulations, the universal insulation resistance tester for measuring the insulation resistance of the test product The test voltage level is 500V and 1000V. The leading insulation resistance tester mainly measures the insulation resistance, absorption ratio or polarization index of the test product, and the voltage levels are 2500V and 5000V. The special insulation resistance tester is used to measure the insulation resistance, absorption ratio and polarization index of the windings of synchronous generators, DC motors and AC motors. Sometimes it is required to measure or calculate the true insulation resistance value. For a test product with a large capacitive load, an appropriate voltage level and a sufficiently large output short-circuit current, a large range of insulation value, and an insulation resistance tester that automatically discharges the tested product are generally used. Otherwise, the resistance of R15S will affect the test value. Large, causing a large error in the absorption ratio test results. For the test site with strong interference, a pointer-type insulation resistance tester should be used because the digital display of the insulation resistance tester has a large jump in the measurement data, which makes it impossible to confirm the true resistance. The interference to the strong magnetic field itself is relatively slow (the damping effect of the mechanical head). Even if there is an impact, the pointer display shows only a slight wobble, and the range of indications is also intuitive. Such as HT2550 series. For occasions with low interference and accurate measurement of the insulation resistance value, a digital display insulation resistance tester should be used because the digital display insulation resistance tester is intuitive and has high accuracy, such as the HT2671. For occasions where large-capacity test articles such as absorption ratio and polarization index are to be measured, an intelligent insulation resistance tester that can automatically measure absorption ratio and polarization index should be selected, such as BC2000.