I'm making a homemade spot welder as a hobby project. I salvaged an old AC stabilizer and recovered the autotransformer. With that core I calculated that I can make a decent 2KW spot welder (well inside the light-medium duty commercial spot welders)
Now, my problem is that, for tiny metal sheets and/or wires I'd like to control the output current of the welder (to set to a max amount, not continous regulation).
I though first in a transformer with a tapped primary in order to reduce the "open" voltage and then control the max output current to some extent with a selector or relays.
Then I realized that make taps into a 2mm dia. wire is somewhat difficult (but not impossible) and let's the winding deformed (I need to attach a bar as secondary or a very big cable) so, begun to think what about a triac control.
I looked for spot welder schematics and there are none with triac control. May be a triac SWITCH (on off) but not control.
Is this impossible? or expensive ? Unreliable to fit in a commercial welder? the primary full current would be no more than 15A at overload (+-10A@220V at 2KW)
Does anyone here have built a spot welder? and tried to do such control?
thanks in advance