Science/Engineering/Technical forums

As I mentioned in another thread a friend gave ma a Hughes VTW-29C Stored Energy Welding Supply. The is a little spot welder for doing things like welding tabs on batteries, welding filaments on and light work like that. Maximum output of 40 Watt-Seconds (Joules), it dumps the stored energy from three 200uf, 450v electrolytics though a transformer to the work head, which I don't have. Found marked inside was the date it was assembled by the girls at Hughes, end of 1961)

Got all the missing parts from it from R5-D3 surplus for $10. I found I had one of the cam lok connectors that fit the panel in my welding drawer and have 5 more coming off ebay for $25 shipped.

Ill probably start by making a basic head from something like an arbor press. The real ones are incredibly expensive, even used. Even cheap ones are $400 on up. About 3/4 the way down on this page, VTA prefix: http://www.emcgrath.com/catalog/welding/welding.html

Here are a few pics, Front:


Hughes VTW-29C Capacitive Discharge Power Supply by macona, on Flickr

Inside in the dark, the big glowing one on the left is an OC3 voltage regulator, the small one on the right is a 12AU7, and the two in back are the 2D21 xenon thyratrons. And below that is a video of the insides working. The thyratrons glow when they are conducting charging the caps.


Hughes VTW-29C Capacitive Discharge Power Supply by macona, on Flickr

Interesting. That on time is lot longer than even the Tung Sol data sheet allows for the high current surge mode. You might need more 2d21's down the road, but fear not - I have the big tube collection, including those.