To withstand pressure test, there are three kinds of sound due to the electrical distance: "crackling crackling": It is the sound of air ionization. "Zi, zi": is the voice of the air stream note. "Pop": loud and crisp, accompanied by sparks, is the insulation (or air) was the breakdown of the sound. The company is located in:
In general, the air discharge is divided into three stages, the first stage is ionization, the electric field is larger, it will enter the streaming stage, in the larger air will be punctured. If you just like the roasted beans "crack crackling" voice, can not insist on a minute breakdown, in principle, meet the national standard requirements. If there is "zi zi" voice, but also insisted on a minute without breakdown, in fact, is in line with the national standard requirements, but the emergence of streaming transformer transformer long-term risk. The main reason for the high voltage noise is that there is not enough air distance between the main airway (HV coil and LV coil). E = U / D E electric field, U voltage, distance between D electrodes. When D is smaller, E is larger. The air withstands field strength of 0.7KV / mm under standard pressure and standard humidity. When the electric field is greater than this value, the molecule will ionize easily. But as long as the air is not breakdown, it will not conduct electricity. By the way, the main transformer airway insulation do not just look at the air, because the high voltage coil also has inner and outer insulation, calculation, the composite insulation should be considered.