looking for a way to make a 12 or 24v powered welder

[Dennis Davis]

I have 12v and 24v battery setups with high capacity (over 500ah). I'm
looking for a way to use a osc and pulse modifier that inturn drives a
bunch of power mosfets with capacitor smothing to provide a current
adjustable supply for welding. Seems like I remember a dual 555 timer chip
providing the square wave and then adjusting the duty cycle with the second
half. If I could then buffer the output of this to drive some 50v 80amp
mosfets(8-10 of them) to provide say 40-200 of adjustable but regulated
current. Using 8-10 mosfets is my way of speading the load as these things
never support the so-called rated current,more like 40% on a steady output.

 

[N. Thornton]

Dennis Davis <huckfinn1963@csinet.net> wrote in message news:<k2yyb.333$Q76.320807@monger.newsread.com>...

I have 12v and 24v battery setups with high capacity (over 500ah). I'm
looking for a way to use a osc and pulse modifier that inturn drives a
bunch of power mosfets with capacitor smothing to provide a current
adjustable supply for welding. Seems like I remember a dual 555 timer chip
providing the square wave and then adjusting the duty cycle with the second
half. If I could then buffer the output of this to drive some 50v 80amp
mosfets(8-10 of them) to provide say 40-200 of adjustable but regulated
current. Using 8-10 mosfets is my way of speading the load as these things
never support the so-called rated current,more like 40% on a steady output.

Easy. Bin all those mosfets. Put the 24v through a big inductor,
insulate the rod holder well, and thats it. The dc R of the coil
controls the weld current. If you need to reduce current add some
series resistance. A protective spark gap across the coil would also
be a wise move.

Regards, NT

 

[Dennis Davis]

N. Thornton wrote:

Dennis Davis <huckfinn1963@csinet.net> wrote in message
news:<k2yyb.333$Q76.320807@monger.newsread.com>...

I have 12v and 24v battery setups with high capacity (over 500ah). I'm
looking for a way to use a osc and pulse modifier that inturn drives a
bunch of power mosfets with capacitor smothing to provide a current
adjustable supply for welding. Seems like I remember a dual 555 timer
chip providing the square wave and then adjusting the duty cycle with the
second half. If I could then buffer the output of this to drive some 50v
80amp mosfets(8-10 of them) to provide say 40-200 of adjustable but
regulated current. Using 8-10 mosfets is my way of speading the load as
these things never support the so-called rated current,more like 40% on a
steady output.

Easy. Bin all those mosfets. Put the 24v through a big inductor,
insulate the rod holder well, and thats it. The dc R of the coil
controls the weld current. If you need to reduce current add some
series resistance. A protective spark gap across the coil would also
be a wise move.

Regards, NT
thanks Dennis