1. The working voltage is too high: According to Ohm's law, if the working voltage is too high and the winding resistance of a coil is certain, then the current passing through is large, that lead to the coil burning out. Need to adjust the voltage and replace the coil.

2 The heat dissipation conditions are not good: improve the ventilation effect, promote the heat dissipation function, reasonably establish the use time, and try to avoid long-term continuous working status.