Why is the sound loud when the transformer is no-load?
Why is the sound louder at no load than at full load? It is because there is no load on the second time at no load, which causes the primary voltage to be slightly higher. Generally, the rated voltage is 10kV, and the actual voltage may be about 10.5kV at no load; the core magnetic density is due to the voltage increase High, larger than the normal design value. B=45*et/S (et is the design turn potential, the number of turns does not change, the no-load voltage increases, so that et increases, causing B to increase); the iron core magnetic density is high, which leads to The hysteresis vibration of the iron core is large, which causes the sound to be louder at no-load; this is the main factor! (The effect is that the no-load current increases) The large no-load current is a secondary cause, and the large no-load current reflects the iron core sheet The quality and manufacturing problems of the good silicon steel sheet; the unit loss of good silicon steel sheet is small, and the no-load current caused by it is also small; the use of more iron cores or the use of bad pieces (large unit loss) will also make the no-load current large; bad pieces The magnetic saturation density is low, so it is also a secondary main factor that affects the sound. In addition, shock absorption measures, iron core and other clamping conditions and iron core design are also factors that affect the sound. However, the secondary reason is to affect the sound of the overall product, not just The sound is loud when there is no load.