we made a Universal input 36w (80v, 450mA) non dimmable design using PIxls design software9 using LNK419eg. It is working fine but the EI35 transformer is becoming very HOT. It is exceeding 103deg C(27degC ambient). Transformer made sandwich construction and got 82.4% efficiency. Primary copper gauge used 24awg and for secondary also 24awg. For ckt diagram we followed DER 286. Can you explain why transformer is heats up? What should be the values for VOR and Kp for this design? Kindly help us to make a design to get low temp and good efficiency .
Spread sheet for trf design is attached.
Since the output is 80v , out put filter capacitor should be higher voltage rated. Shall I connect 2no's of 1000uF/63v capacitors in series instead of a single 500uF/160v.