Miller Synchrowave 350 LX Wiring and use Question

Greetings all,
After much wailing and gnashing of teeth, the boss got us a new Miller Synchrowave 350 LX on demo to try out. We have an ESAB 252 which is a
refurbished/remanufactured machine. I have asked for help here before with it and received some good advice, but it seems to be in its final throws. The ESAB has a bad habit of welding good on DC welding carbon and SS, but goes ignorant when welding Alum. We even installed a new PC board,(the old one had a burnt up resistor or capacitor) but to no avail. $500US, and they said it was a cheap one. Anywho, it is still not right, the high freq will "light", but it will not form an AC arc without scratching the tungsten. Welder is set at 250 on the dial(max), foot pedal being used, 1/8" pure tungsten with gas lenses, water cooled 250 amp torch, running straight Argon at times or 75Hel/25Arg at approx. 20-25 cfh, This was supposed to be 75Ar/25Hel, but Holox/Linde can't seem to get it right, they initially brought us 75Arg/25Co2. GGGRRRR!! Had to replace 400 amp torch(you _can not_ roll the welder over those coolant lines) with the 250, but it seems to be handling it, sort of, but I'll explain that later. Material being welded is 1/4" wall tubing(4x12) and 3"x3"x3/8"x6" long angle, both 6061, filler metal is 5556. The angles are lying flat onto the 12" side of the tubing, being welded on 3 sides. The person welding these is not pre-heating, he says the welder should get it hot enough. What can you do? As I mentioned above, the ESAB will weld after you scratch it, but it still is not "right", the arc sounds way too harsh, like the arc is about to destabilize. Hope that makes some sort of sense.
OK, on to the Miller. First the wiring question. Our shop has 3 phase power, meaning we have 240v, 120v and a 208v leg. There are 3 hot legs, between any 2 of the 3, you get 240v, from 2 of them to ground you get 120v but from the third to ground you get the 208v. Everybody still with me? I hope so. The wires feeding the Miller are the same that fed the ESAB, BTW, and one of them is the 208v leg. The welder is set up for 230v. QUESTION, finally. Could the 208v leg cause a problem with the Miller? More pointedly, is there anything in the welder that could be trying to run on 120v that this 208v leg could screw up?
Secondly, set up and use of the Miller. For whatever reason, we did not get the TIGrunner kit with this machine. We are using a QC brand(ESAB?) torch, Q20-25, which hooked up to the front of the ESAB and was plumbed out the back to a Pro-Cool(?) cooling rig sitting atop the welder. We were able to connect the cooling rig to the Miller successfully, after burning up one torch kit due to no circulation of coolant. GGGRRR!! Finally got everything plumbed right and used the following settings; Same torch, tungsten and gases as above, machine set at 250 amps, Balance seemed to work best at 3, but a later call to Miller advised 7 which did not seem to work. Using the straight Argon we were not able to form a puddle to begin welding. Using the Hel/Arg mix we could form a puddle, however the tungsten could not handle it. The guy welding would simply break off the end of the tungsten with a pair of lineman pliers and begin welding, the tungsten forms a ball atleast 3 times the diameter of itself and it is very unstable. It just sort of hangs there looking like it will fall off at any second until eventually either the cup explodes or the tungsten does fall off, I never really got that much information from the guy. I guess my QUESTION is, What could be causing the tungsten to ball up so big and be so unstable? The salesman suggested it could be that the gas is too hot, maybe? I know that the flow on the gas is too high, I tried to tell him that and turn it down but I think he turned it back up.
I realize this has gotten to be a huge post, I hope some of you can stay with it long enough to help me. I will check on it frequently tonight, Wednesday, as the boss has an electrician and another/more experienced salesman coming to look at it in the morning.
Thanks for any and all help, Jim C Roberts
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An ESAB Heliarc 252 should be able to do this, but it will definitely need the Helium/Argon mix. Definitely a 5/32" Zirconium Tungsten.

Inside the back of the Syncrowave is a bar with little copper jumpers on it. Set the jumpers for what power you are feeding it.

What you are doing is right at the outside limit of TIG. Why not MIG these parts with a spoolgun. You can run a Miller 30A spoolgun from the Syncrowave, and it will give you much faster easier welds on aluminum this thick.
Heck, for what the Syncrowave cost you could buy a new Cobra push-pull gun and run it from the ESAB Heliarc 252.
Anyway you need to step up to 5/32" Zirconium tungstens to handle that kind of heat. Even better would be to move up to a 500 amp torch and use 3/16" tungstens. Helium-Argon will help a lot.
250 amps is too low.
basic amperage rule for steel and aluminum is 1 amp per 0.001" of thickness, for a flat butt weld full penetration, single pass. Add 1/3 for inside fillet weld. Subtract 1/3 for outside fillet weld.
So your heavier material is the 3/8" aluminum angle. 3/8" = 0.375 = 375 amps. Because your base metal is only 1/4" you can skip the adding 1/3 for an inside fillet weld

OK, as a welding instructor and professional welding consultant, you are using the wrong process.
What you really need is at least a spoolgun so you can MIG weld them. If you can afford a Syncrowave 350LX you can afford a Miller XMT 304 power supply and a push-pull feeder like Miller's XR-Edge or a Cobramatic.
A Lincoln PowerMIG 300 would be an excellent choice here, but you will be running near it's upper limit. As would Miller's version the Millermatic 351.
If you insist on TIG welding these parts, then at least use the right technology. What you need is an inverter power supply. Inverters make aluminum welds much easier. A Miller Dynasty 300DX is a great machine for this, and you will be near it's upper limit, but inverters get much higher penetration on aluminum per amp than transformers.
.
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power, meaning we have 240v, 120v and a 208v leg. There are 3 hot legs, between any 2 of the 3, you get 240v, from 2 of them to ground you get 120v but from the third to ground you get the 208v. Everybody still with me?<<
That doesn't sound right and might have something to do with the problems you're having with the ESAB.
You should have 3 legs that are each 110V to ground. If you measure from any leg to any other leg you should have 208V but you should not have 208 on one single leg to ground and 110V on the other two to ground.
And if you do have 208 on one of them and 110 on each of the others you definitely should not be able to measure 240 between any two.
I'm not an electrician but I have a fair bit of experience working on 3-phase equipment and I can't imagine any situation where you should have what you say you have.
Best Regards, Keith Marshall snipped-for-privacy@progressivelogic.com
"I'm not grown up enough to be so old!"
"Jim C Roberts" <jimnthem_AT_comcast_DOT_net> wrote in message

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I thought you only got 208 on Wye connected 3 phase. You also get 120v off each individual leg to neutral in 208 Wye.
Shawn
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"Shawn" <shawn_75ATcomcastDOTnet> wrote in message

off
As Gunner pointed out, this is a 240 delta with one leg center tapped. A little bit of trig will show why this is so...
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Should have read "one PHASE center tapped"...
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