Safety testers (also named hi-pot tester/hipot tester/hipot test) are designed to ensure safe operation of DUTs under various operating conditions and environment.
Dielectric withstanding test was the original official name, and it is commonly known as High Potential test and it has evolved into Hipot for short in the industry today. A hipot tester is a specialized electrical testing instrument that is used to test the electrical insulation of wires, cables, and other electrical equipment to withstand high voltage. High Potential Test also refers to the high-voltage test.
Why is hipot testing important?
Withstanding voltage, insulation and grounding resistance (Ground Bond) are the test functions of the electric safety tester. Among them, the withstanding voltage test is a required test item for electrical equipment before leaving the factory.
How to choose the output capacity of the withstanding voltage tester?
The output capacity of the withstanding voltage tester is in VA, which refers to the product of the maximum rated AC test voltage and the maximum rated current. At present, 100VA/200VA/250VA/500VA withstanding voltage testers are available on the market. Taking AC 5000V as an example, 500VA can provide 100mA, and 200VA can provide 40mA. The output capacity actually depends on how much current is required to maintain the test voltage. We expect to establish enough test voltage on the insulation resistance to be tested to confirm whether the insulation is good. When the insulation breaks down, the insulation resistance will reduce. If the current at this time is insufficient (insufficient capacity), it cannot establish a sufficient voltage in this resistance with a decreasing value.
This phenomenon is similar to the DC power supply switching from CV mode to CC mode. When the insulation resistance is very large (the load current is small), and when the insulation breaks down, the insulation resistance becomes smaller (the load current becomes large), and the capacity is needed to support it. Therefore, the destructive experiment of materials in the R&D unit or the laboratory of the third-party manufacturer will require a capacity of 500VA. The routine test of the production test commonly utilizes 100VA model. The reason is that the yield rate of the product is very high during mass production. Taking the insulation resistance of 100MΩ as an example, to establish a test voltage of 5000V, the load current is only 50μA and to establish a test voltage of 1500V, the load current is only 15μA, which is more than enough for the capacity of 100VA. Of course, if it is AC withstanding voltage, the influence of equivalent capacitance must be considered.
Why GW Instek is your best choice?
We can help you safely complete the tests when analyzing insulation materials or conducting production testing. For more information, please visit white paper” Is Your Hipot Tester Safe? Ten Whys of Electric Safety Testing” .