stud welding story

I just could not hold back on this actual event that happened over ten years ago. I was working as evening lead hand in a structural shop. The day foreman was a highballer and had a real close one. Our stud welder at the time was a 1500 amp unit that could handle 7/8 inch diameter studs. It was a cranky old machine that gave all kinds of bad shots making for repairs on bad stud welds. This one day it just plain shut down. The foreman decided to correct the matter so the first thing you know he had taken the cover off. Discovering that all the insides was choked with a heavy layer of shop dust he decided to blow out the dust. Since there was no ready source of compressed air nearby he grabbed a cutting torch and proceeded to blow it out with oxygen. Oh Yeah ... one other LITTLE thing. He didn't bother shutting off the main fuse box. If you have seen capacitors in a smaller welding machine you ain't seen nothing since this baby had to pump out 1500 amps for a fraction of a second. The torch tip touches some metal part in the machine and there is not only an arc but one big dust explosion. The foreman's face is burned red and is sunburned for about a week. The torch end is melted and the machine itself has to be replaced. This is a thirty man shop so it is big. The people in the office felt the concussion. The guy was lucky he was not killed. I came on shift to hear the tale and the foreman had gone home for the day..... most likely to change his pants. Randy

Reply to
Randy Zimmerman
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The torch tip would have had to hit "two" parts to conduct. Maybe the body of the torch was resting on the frame/case, and the tip hit a capacitor terminal or someting. Also, wonder what kind of "shop dust" this was? Wood/sanding dust, etc ?

Since a capacitor can discharge at I=C*Dv/Dt, yeah, the concussion can be a sharp one with a pretty good shock wave. I was present whan a

10,000uF bank charged at 750Vdc was discharged with a sliped meter lead, and it was a violent shock wave.

Did he get in trouble for this action I wonder?

Reply to
Mr Wizzard

I would guess the dust was mostly steel / iron oxide. Him get in trouible ???? He was the foreman :')))

Reply to
Randy Zimmerman

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