Need Help With A Mini Spot Welder
I've been trying to gather information to build a welder for a special application. The use is for welding the commutator tabs and magnet wire that passes over them for small DC motors. While there are specialized and often automated welders made for this purpose, they are both large and very expensive and really intended for industrial users. I have been able to get small bits of information as to how others have done this, but it's been difficult to get the whole project laid out (there is apparently some "secrecy" involved here!?). The materials being welded (soldering isn't a preferable way to make this connection...these motors run hot and very fast) are the brass commutator tabs (approximately .030" thick material about .060" wide formed as a "U") and the copper magnet wire used to wind the poles that then passes over each brass tab...from #23 awg to #28awg.
From what I've been able to gather, people have done this on a "homebrew" basis using 6V automotive battery chargers/starters that can deliver around 30 amps or more. I have very little knowledge of electronics and none at all about welding and circuit design, but am looking for information on how I might proceed after sourcing the charger/starter. I'm guessing that the "negative" cable would be adapted to use as a clamp at the commutator and would also double as a heat sink to prevent damaging the commutator and that the "positive" cable would somehow be adapted to hold some sort of fine rod that would touch each com tab to complete the welds.
-Maybe a footswitch could or should be used to start/stop the weld?
-Is the positive cable simply used to hold a rod for the "spot weld"?, or are there other pieces that need to be added? To my mind, it would seem that simply touching the positive to the commutator tab to make the weld and complete the circuit would simply trip a breaker at the panel or any protection device on the charger(dead short!?).
-Any other information or thoughts?
Thank you in advance