I have an XMT304 with a 12vs feeder. If the LN25 is like the rental ones I have used all you need to do is connect the feeder to output on the machine. This may require you making up a lead or adapter depending on the machine and feeder connections. Set the machine to "VS Feeder". Make sure the sensing lead on the feeder is either clamped on the ground or the same part the ground is on or it will not turn on.

To give the feeder gas, you need a regulator with an extension hose.

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Set the machine to "VS Feeder".

Chris T is right on with the feeder, only thing I would add is to be sure feeder is set to CV on the switch.

I'm not sure you have the option to set the machine for a VS feeder on a CC only XMT304. I have a feeling to use the feeder you will need to run it like it was being run off a standard CC engine drive, so you would set the machine for stick.

Same issue applies with the LN 25. Since he has a CC only XMT, you would set the feeder for CC not CV.

To the OP... While a VS style feeder like your LN 25 will allow you to run wire, it will not be like running a more typical stand alone mig machine or wire off a CV capable XMT. Because you will have to run in CC mode, the feeder will attempt to mimic CV by constantly attempting to change the wire speed, rather than the constant wire feed that happens when using a CV power source. Most think of "mig" as a short circuit process. In short circuit, the feeder can't make the wire speed adjustments fast enough to mimic CV well. To do so you need to get the amps up into spray mig. Spray mig is a hot process and poorly suited for thin materials or vertical or overhead welding. If you use FC wire and have the amps up into spray, this rig will lay down a lot of material in a hurry and guys often use this in the field to do heavy weldments. It's not really a sheet metal rig.

 

Chris T is right on with the feeder, only thing I would add is to be sure feeder is set to CV on the switch. For Tig, the lift arc works very well on the XMT machines. I would try it and see how it works for you. You could add a pedal or fingertip control to the 14 pin connector. If you desire HF start, a unit like a Miller HF-251 would be needed. For a torch, get a 17 series with a gas valve.

 

I've never run HF TIG on one of these units, but the lift arc TIG does very well on both this machine and the Lincoln equivalent, the V-350 Pro. Personally, I prefer the Lincoln.

That said, to run TIG, the easiest option is to just get a torch with a manual valve and run the hose direct between the torch and the flowmeter. Just remember to turn it on and off, otherwise you'll roast your tungsten and/or waste gas.

 

Thanks very much for the info. I took both machines to my LWS to have them checked out. Since I have no experience with this setup, I think having an experienced Tech check them both before I fry something ( myself included) is a good idea. I noted the sensing lead clamp was really lame and had no spring tension to keep it connected and the line lead on the LN25 was thread bare where it comes out of the case. 250 amps could light up quite a lot, again me included.

 

DSW, Chris, Hillbilly, MJD, thanks for your input and guidance. I have a 17 torch for Lift Tig. It is only a 150 amp air cooled, but it does have a gas valve. That should allow me to play on the lower end of this unit's capability until I can get something that will take the heat. I am not sure that I will be using the wire feed any time soon, but it is good to know that it can handle spray transfer for heavier welding.

I truly appreciate all the help.

 

Did Miller make a CC only XMT304? Why would you need a high frequency for TIG? You can't do aluminum and unless it's critical work no need for the expense of a high frequency.

 

You don't "need" HF for DC TIG. However, it's one of those things that everybody seems to be conditioned in to thinking they need in a TIG welder. They either don't know how to utilize a CC power source for scratch start TIG, or they just can't do it well.

That said, even with lift arc or scratch start, a competent welder can produce x-ray quality welds day in, and day out. No HF necessary.

 

Yes Miller did make a CC only XMT 304 in the past. They aren't as common as the CC/CV units are. Guys occasionally get caught buying used not realizing that they are getting a CC version vs the CC/CV version most are more familiar with. It was probably designed for shops that do a lot of pipe where they only did DC tig or stick and had no use for wire.

 

No expert, but if you were going to use the feeder much I would look for a CC/CV power supply. I think in the long run you would be more satisfied.

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