What is the difference between AC Hi-Pot Testing and Impulse Testing?
AC High-Potential Testing is a type of high-voltage insulation test used primarily to evaluate the insulation strength and safety of electrical equipment or components. It is carried out by applying a high-amplitude alternating voltage (usually 50Hz or 60Hz industrial frequency alternating current) to the insulation system (such as between the positive and negative poles), to detect defects in the insulation materials (such as breakdown, short circuit or excessive leakage current).
Test principle: After applying high-voltage alternating current, monitor the leakage current. If the current exceeds the set threshold, it indicates that the insulation is defective and the equipment may fail.
This is a destructive test because high voltage may cause permanent damage to the insulating material (for example, when the voltage is too high or the duration is too long during the test)
There are main differences between AC Hi-Pot Testing and Impulse Testing. Both belong to high-voltage insulation tests, but they differ significantly in purpose, waveform, and application scenarios.
Test waveform: AC hipot testing is a Sinusoidal AC voltage (50Hz/60Hz), continuously applied (in seconds or minutes). Impulse testing is short pulse waveforms (such as 1.2/50 μs), with rapid rise and fall (microsecond level).
Test purpose: AC hipot testing is to evaluate the long-term insulation strength and safety (such as detecting welding defects or material aging). Impulse testing is used to evaluate the instantaneous overvoltage tolerance capability (such as lightning protection or surge protection).
Common standard: AC hipot testing is IEC 61010, and impulse testing is IEC 60060
Leakage current monitoring: AC hipot testing is concerning (excessive current indicates an insulation defect). Impulse testing pays less attention to the current, and more emphasis is placed on the voltage peak and the breakdown phenomenon.