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Registered Member #1225
Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253
I have a core from a 12kv 60ma 720VA NST, plus the primary. If i where to take shunts out, how much can i expect it to output. 1.5kw? 3kw? I have no clue.
Duty cycle would be something like 50% or so over the course of 10 minutes.
I intend on making a small AC arc welder of some sort. Just for hobby use.
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
An arc welder will need some kind of ballast/current-limiting, so keeping the shunts in may be a good option, in which case the output would be a 'scaled' version of it's original spaecifications, e.g. 120 V open-circuit, 6A short-circuit.
If 120 Vac is enough to start an arc then using just the primary as a ballast choke would be easier, not needing a new secondary.
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
I have an old NST which drew I think 320VA with the shunt in, and with it removed the input power increased to 690VA. I can run it for around 5 minutes on a jacobs ladder before the coils get hot.
Registered Member #2099
Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716
Arcstarter wrote ... I have a core from a 12kv 60ma 720VA NST, plus the primary. If i where to take shunts out, how much can i expect it to output. 1.5kw? 3kw? I have no clue.
I agree with Sulaiman, you need ballast for an arc welder so the core shunts are good. I hope you are thinking about a very small welder.
I suspect that your NST wasn't ever a 720 VA unit. The rating isn't 12 kV at 60 mA. You get 12 kV at 0 mA, 0 kV at 60 mA, or intermediate combinations. This excellent reference pegs it at 400 VA:
Registered Member #2463
Joined: Wed Nov 11 2009, 03:49AM
Location:
Posts: 1546
While considering futures for MOTs and NSTs to be stripped, does anyone know a good way to remove the copper from the remains of windings to render it into ingot form for reuse is other non-electrical, ie non 99.997% purity? I am sure artisians would like copper at less than the market price. edit; And while doing that, perhaps discover a way to case-harden it.
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What is the largest amount of power an NST core can handle?
