1. What is voltage withstand test?
Voltage withstand test is one of the most common safety tests, the common dielectric withstand, high potential, hipot test are referred to voltage withstand test. The main purpose of voltage withstand test is to test the insulation capability of DUT (Device under Test). Therefore, when the equipment in operation, the test point to apply a high voltage, test whether there is insulation damage (Breakdown) or electrical flashover (Flashover/ARC) occurs.
2, how many types of insulation in the safety regulations?
There are four types of insulation: basic insulation (Basic), auxiliary insulation (Supplementary), double insulation (Double) and reinforced insulation (Reinforced). Due to the product may be due to excessive dust, humidity or other reasons lead to discharge along the surface, so it is also necessary to voltage test to determine whether the internal circuit design of the product along the surface of the distance or insufficient insulation and other issues.
3 、Why do I need to judge the real current during the AC withstand voltage test?
AC output total current (total current) may be due to part of the internal reactance caused by the difference between the real test current (real current). When the current is being output, if it is subjected to a large amount of reactance, the reactive current will be larger, making the real test current relatively smaller. If you can not accurately measure the output current and to compensate, it will cause a blind spot on the test.
4, in the DC withstand voltage test, why need to slow up time?
DC withstand voltage test usually need to add a slow rise time and discharge time, because most of the DUT has a capacitive and will lead to charging current generation. In order to stabilize the charging current (charge current), it is necessary to buffer the ramp time so that the leakage current is not too high due to the charging current, and then judged as a defective product (FAIL).
5 、Why do I need to slow down the time when doing the withstand voltage test?
The withstand voltage test will make the DUT charging, so at the end of the withstand voltage test must be a period of time to discharge, good withstand voltage test equipment will minimize the discharge time, and in the discharge standard will be clearly marked before the danger warning to prevent testers from improper contact with the electrical injury.
6, what is flashover Electrical flashover (ARC)?
Safety standards clearly pointed out that there should not be insulation damage (Breakdown) occurs, and part of the safety standards require that there should not be electrical flashover (Flashover / ARC occurs, but there is no absolute test standard. ARC is a kind of electrical discharge, when the ARC occurs has indicated that the insulation capacity has been insufficient, and if many times of the ARC occurs, will lead to the destruction of the insulation. The ARC is a type of electrical discharge, and when it occurs, the insulation capacity is insufficient.
7. Why do I need to do voltage compensation?
In the withstand voltage test, the test voltage standard is one of the main factors to judge the good product. Many withstand voltage test equipment to transformer will be converted to high voltage output, but the internal impedance of the instrument will cause voltage division, especially in some poor quality withstand voltage test equipment, the actual output voltage can not meet the safety standards. In order to avoid errors in determining good products and cause unnecessary trouble, good withstand voltage test equipment will be automatic gain compensation (Auto Gain Compensation) to correct and compensate the voltage to the required voltage value, and the voltmeter is designed in the output, in order to correctly measure the output voltage is not enough.
8 、What is Ground Impedance Test?
There are two test methods for grounding protection: Ground Continuity test (GC) and Ground Bond test (GB). The purpose of the grounding protection test is to prevent the user from improper current generation, the current will flow to the earth, contact with the body will not lead to electrical hazards.
9, what is insulation resistance test?
Insulation impedance test and DC voltage withstand test is very similar to the two points associated with the application of DC voltage (50 ~ 1000V), you can determine the good and defective products. The insulation impedance test is a non-destructive test and can detect whether the insulation is good or not. In some specifications, the insulation impedance test is done first and then the voltage withstand test is performed, and when the insulation impedance test fails, the voltage withstand test often fails as well.
10. What is leakage current?
When the current overflows after the insulation impedance, it is called leakage current (Leakage current), when the leakage current is contacted by the human body, the current flows to Earth after the human body, which causes electrical injury. Leakage current test is different from voltage withstand test and grounding protection test in that the equipment is tested under operation. The leakage current test will be added to a human body simulation impedance circuit, which can simulate the size of the leakage current through the human body in real situations.