KES-1600 / HBS Stud Welder

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awemawson:
There is a welding style lead to the gun via a 'dinze' plug, then also a multi-pin plug / socket. The gun has a trigger that is obviously just a switch. The main box lights up a lamp when the spring loaded gun is pressed against the work, so that's just detecting an earth on the shroud.

So again just assumptions, but the only active thing coming back from the gun is 'trigger pressed'. There is a light over the setting dial that goes green when ready, but if you move the dial up or down it takes a few seconds to go back to green from the red it shows as you move. So I assume it is measuring the volts on the capacitor bank and comparing with the 'set point' from the dial.

vtsteam:
I see, and I guess the caps are probably charged to a relatively low voltage, so that would solve the puzzle to me of the need for a step down transformer on output. If they are never charged very high, no need. But they do need to be huge to store enough power and supply the instantaneous welding current. Well 66 thousand microFarads, is a respectable capacity!

Fun to pick this stuff apart...

vtsteam:
Oh, just noticed you attached the manual -- now RTM'ing... :coffee:

vtsteam:
Looks like the limit is 6m x 20 mm studs. The chuck is special, as are the studs -- copper coated, and they have a small pin at the tip, which probably sets up the resistance needed for the initial melt. The weld pool (if you could call it that) then probably eases further melting of the larger stud, and it's now high temperature continues to provide enough resistance for the larger area melt. This is all taking place in an instant.

There's spring loading, is it a continuous pressure or is there a momentary hit? They refer to an "impact pin".

btw, I definitely wouldn't want to build one (kidding earlier) but do love to understand how things work. This is a particularly fascinating tool! :coffee:

awemawson:
Steve, that's not really a manual, more a guide written by some firm that are using one for only two sizes of studs. I think it'll actually do 8 mm.

Stud is just mild steel, as you say copper plated and with a pip on the end. It is held in a simple four fingered collet made from copper, and the fingers are held together with an O ring. Up the back of the collet is an adjustable 'depth stop' to adjust for different lengths of studs. If I get a chance I'll pull the back off and measure the voltage on those capacitors - I suspect it's not going to be that low - 150v is my guess but time will tell. My guess is based on them being 200 v rated. To last they need to be under rated, but no manufacturer is going to pay for higher voltage caps than they need as I bet that they are rather special and pricey.

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