kbernhof 1 Posted November 27, 2008 Report Share Posted November 27, 2008 i need help because im building a homemade spot welder and i need some input. i hook up transformers and when i flip the switch, the transformer blows. what kind of transformer should i use? Link to post Share on other sites
verne 1 Posted April 12, 2009 Report Share Posted April 12, 2009 how many transformers now? a spot welder is sometimes called a resistance welder. put a resistance into a circuit and pass a current through it and it will get hot. that is the principle employed with spot welding. a couple of bits of sheet metal can hardly be called a resistance by any stretch of the imagination, but that is what they are - or at least with the aid of the points on the electrodes this is the highest resistance in this particular circuit even though it will measure only a small fraction of an ohm. this is a clue to the sort of transformer that must be employed...the transformer must be able to supply more current than will flow through that resistance in order to create enough heat to complete the weld.ohm's law states that at one volt a current of one amp will flow through a resistance of one ohm which means a current of one thousand amps will flow through a resistance of one thousandth of an ohm at one volt...i don't know the exact figures but a spot welding transformer supplies a truck load of amps at a very low voltage.i hope this helps even though you have probably found this out for yourself by now. Link to post Share on other sites
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