Miller 250 TIG "Return to light" project

Do you know the amperage of the breaker on that circuit?

Also, has anyone checked the spark gaps?

50 amps I believe. I feel reasonably confident on that. Supposedly it requires 100 for the AC to work well

Iā€™d guess the answer is ā€œnoā€.

Per the manual:

2 Spark Gap

Normal spark gap is 0.008 in (0.203 mm).

This can be checked, with the input breaker OFF, via an access door and a feeler gauge.

Iā€™d say, yeah, weā€™re a skosh under-sized on that feeder. :slight_smile:

(edit: Hey, how about we get that converted to a 460v feeder? :-))

Lol. Yeah letā€™s call Oncor to set a new transformer.

Iā€™m not serious for those who canā€™t sense my sarcasm.

2 Likes

Well, they work both ways. Just need a 240v -> 460v in the electrical room. :smiley:

http://www.ebay.com/itm/Square-D-30-KVA-transformer-3-phase-Used-Transformer-30T6H-480V-240V-/262816854512

On a more serious note, hereā€™s a better table of the required circuit amperage:

Iā€™m guessing a 175 ampere circuit to the metal shop is pretty much out of the question, right?

(edit: That 460v transformer for $300 is starting to look like a good idea, eh?)

Hadnā€™t thought about that, but yes, there is a way to physically limit the current. The foot switch, in TIG mode, is just a rheostat. Lower resistance == more current, or at least thatā€™s what I would expect. Pretty easy to check that. Just add some resistance inside the Miller box which canā€™t be removed and you effectively limit the highest amperage which can be obtained, irrespective of the knob on the front of the box.

1 Like

I have been told it was checked, but I was not present for the checking.

How about a ā€œScald-guardā€ faucet style fix, wherein we put a limiter on the knobā€¦

Down fall to a transformer like that is you will about double your input current compared to the output. I donā€™t think we have that much power.

Psssst Oncor giving gods please set us another secondary transformer. Lol.

1 Like

So while thinking about the new pump, I realized we did not buy a new coupling for it. Now there may be a chance that they sent a new coupling with it. I can make one to place in there or someone else could 3D print one as the one in it was plastic. Or perhaps we could spend the 6$ to buy one. The ones that I have seen online were brass.

So I may run over to Grainger in downtown Ft Worth to get a coupling.

Just catching up here with the welder and the circuit. I donā€™t think we can get 480 volt service at our current location. This would require changing the transformer outside the building. I will call Oncor and double check what we can get. A 200 amp circuit for 208V is likely cost prohibitive but if someone wants to get a quote go for it (assuming we have a panel that could even host it because thatā€™s half a panel).

Yeah Luke, it would likely be very cost prohibitive. Iā€™d be willing to bet that it would be in the 10ā€™s of thousands of dollars to do.

I called Oncor. They didnā€™t know details about our transformer but said theyā€™d have a specialist call me within a few business days with the information on it.

3 Likes

Two new couplings. Not exactly the same either.

2 Likes

Iā€™ll be at the space tomorrow for the antenna raising. If you happen to be there, we can take a look.

After a discussion with Lee over the weekend, I rescind my earlier objection to selling the 351 & 250. A couple of nice inverter units (he mentioned Miller Dynasty) funded with the proceeds of these two sales would be great.

Weā€™d still need to up the breakers just a bit to 50A circuits, but this is a better plan than what I originally proposed.

1 Like

Itā€™s on the list to get the pump in. Lol. Didnā€™t get a chance to get to it today.