I want to design a transformer ideally for arc welding purposes. The thing is that I want it to be designed in a way that the windings allo overloading of the transformer itself.
For example I had a transformer from old radio, the area of core of the transformer was no more than that of a normal 100 watt transformer but when I shorted the secondary leads of transformer at around 40 volts the calculated power output was 650 watts! The varnish inside the transformer started boiling after a minute or so. But I used that transformer for two years, at least at 200 watt (not full time).
Now the thing is that this property of being able to be overloaded is related with number of turns per volt of the transformer. To be more specific, in normal transformers we divide 7.5 by core area in inches to get number of turns per volt. I know that to make "overloadable" transformer we have to do with this number (7.5) but I want to know figures to be in safe range without tripping my breaker at no load or frying the transformer before I even put any load on it since these transformers have high no load current, and have a working transformer at the end.
Thanks for reading my question.