Haha that's the easy part.. :-)
Output 50V 1.2Adc (regulated, can drop 1 or 2V at full load) centre tapped (+ and -25V), current draw can vary from almost 0 to full. Again not too hard.
Input range 35Vac-46Vac, no sweat.
Isolated-Sine wave current draw and unity power factor (or close) :shock: well at least for me. No large input caps for starter as I understand.
This project has been on and off for several years, now it seems back on. I have looked at National switchers and a few will handle the input and output voltage and current requirements but ideally I would need a similar device as those used in universal power supplies with 90-230Vac inputs but for lower voltages in.
Have tried Power Integration but they are really not that interested. May have several hundred unit per year sale.
Did I mention it should not cost much more that the current 240V 50VA transformer?....