We have a 250 Watt SMPS operating at 50 KHz. The transformer core consists of two identical E-cores with an air gap between 3 to 4 mm. The bobbin has two segments with separation exactly at the centre. The primary is wound on one segment and the secondaries in the other. The air gap happens to lie at the separation between the two sets of windings. The transformer gets extremely hot only a few minutes after the SMPS is switched on. Upon investigation it was found that only the portion of the windings around the air gap was getting hot, so much so that the bobbin (made of plastic) in that region had melted. We would be very grateful if someone could explain this phenomenon and tell us what steps we have to take to prevent this heating effect.
Excessive Heating of SMPS transformer
Re: Excessive heating of SMPS transformer
