What is withstand voltage test?

Withstand Voltage Test is a common method for testing the insulation capability of electrical appliances, electric equipment, electrical devices, and electrical circuits. Withstand Voltage Test is divided into two types: AC Withstand Test and DC Withstand Test. The former uses test voltage several times higher than the rated voltage of the tested product, while the latter observes the value of leakage current under different voltages to draw the current-voltage characteristic curve for analysis.

The application period of high voltage for different insulation components is also different, such as ceramics and liquid insulation using 1 minute of high voltage pressure; organic solid insulation using 5 minutes; voltage transformer using 3 minutes; and oil-immersed power cable using 10 minutes. Withstand Voltage Test can detect insulation issues, dampness, and aging phenomena of electrical equipment. This type of test is very important and it is necessary to strengthen the withstand test of new products or products that are already in use in order to ensure the safe use of electrical products.

Basic Principle of Withstand Voltage Test:

Apply high voltage higher than the normal working voltage to the insulation of the tested equipment and monitor the changes of leakage current for a period of time. If the leakage current is kept within the specified range, it can be determined that the insulation structure and function of the tested equipment are good and it can be safely operated under normal operating conditions. Withstand Voltage Test can detect whether the leakage current of the tested equipment is sufficient and whether the electrical insulation has continuity.

The method of Withstand Voltage Test includes hydrostatic test and air-pressure test. The specific requirements are as follows:

1. Hydrostatic test: Air in the container should be exhausted before the test. Pressure can be applied only when the wall temperature of the pressure tank is roughly the same as the liquid temperature. The pressure should be slowly increased to the specified test pressure and maintained for 30 minutes. The pressure is reduced to 80% of the specified test pressure and then inspected. For spherical tanks, it should also meet the requirements of 8.10.4.4 in GB 12337-1998.

2. Air pressure test: The test should have safety measures, which must be approved by the technical director of the test unit. The pressure should be slowly increased to 10% of the specified test pressure and maintained for 5 minutes. All welding joints and connections should be checked for leakage, and then the pressure should be gradually increased to the specified test pressure and maintained for 30 minutes. Then it should be reduced to 87% of the specified test pressure and inspected. For spherical tanks, it should also meet the requirements of 8.10.5.5 in GB 12337-1998.

The purpose of Withstand Voltage Test:

Withstand Voltage Test is to evaluate the insulation performance of the product, applying voltage far above normal conditions and measuring the leakage current to improve the safety of the electronic product. Withstand Voltage Test is divided into long-term test and outbound test. Long-term test is used to evaluate the insulation performance of the product. Outbound test is short in time and widely used in industries such as switch factory, wire and cable materials factory, etc.

What is AC/DC Withstand Voltage Test?

AC/DC Withstand Voltage Test is a multifunctional electrical safety testing equipment, combining analog and digital technology for AC/DC withstand test of the tested product and insulation material to evaluate its resistance to high voltage. In addition, it can also detect parameters such as leakage current and insulation resistance during testing to evaluate the insulation performance and improve the safety.

The technical specifications of AC/DC Withstand Voltage Test include test voltage range, test current range, test accuracy, leakage current monitoring, insulation resistance monitoring, display mode, safety protection and more. The test voltage range often ranges from 0 to 5 kV or 0 to 10 kV, the test current range usually ranges from 0 to 20 mA or 0 to 30 mA, the insulation resistance monitoring range often ranges from 0 to 50 GΩ or 0 to 100 GΩ, the display mode may include LED digital display, LCD liquid crystal display, or color touch-screen display and the safety protection setting includes overload protection, over-voltage protection, etc. to ensure test safety. Furthermore, the test accuracy of AC/DC Withstand Voltage Test will directly affect the accuracy of the test results, so high-precision instruments should be purchased.

When operating AC/DC Withstand Voltage Test, the following points should be noted: proper grounding connection must be made to ensure the accuracy of test results and the safety of the operation personnel. Before testing, it should be checked whether the tested product or insulation material meets the national and industry standards to ensure the reliability of the test data. The operation personnel should receive professional training to familiarize with the usage and precautions of the tester and avoid operating errors. During testing, the voltage and current should be controlled to avoid exceeding the rated value of the tester. After the test is completed, the power should be disconnected and the tester should be cleaned and maintained to ensure long-term stable and reliable operation.

In conclusion, AC/DC Withstand Voltage Test is an important electrical safety testing equipment with multiple functions and technical specifications. Safety and precaution should be taken when using it to ensure the accuracy of the test results and the safety of the personnel.

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