just bought a millermatic 250, need help with power hook-up.

[1967marti]

I justbought a millermatic 250 for a pretty good price... It was wired to a breaker box so it didn't come with a plug, when they removed the unit to sell they removed the cover and disconnected the power cables from the inside of the unit (to re-wire the replacement). Where do the two power cables and ground hook to inside of the unit?
It kinda looks like the two power cables hook to the power switch and the ground gets bolted to the "floor" of the unit? Does this sound right?


thanks!

[pin2hot]

It kinda looks like the two power cables hook to the power switch and the ground gets bolted to the "floor" of the unit? Does this sound right?

Yes

[H80N]

Do not know if it is a straight MM250, or MM250X or MM250X w/meters or MM250MP....

here is the manual link....

just plug in your serial number and it will come up with the proper manual for your machine.... the manual has the hookup diagrams and info...

http://www.millerwelds.com/service/ownersmanuals.php

[1967marti]

Thank you for the replies. The manual doesn’t have any internal hook-up pictures, I had to call miller. When I asked about the lack of internal pictures I was told "well we don't want people rewiring the inside of the machine" LOL! Which I understand 100%. It seems that my new-to-me welder came out of a shot that all of their big welders tied to a power-box and not connected with plugs, so they just opened it up and cut the cables next to the switch to save the cable for the next one.

I got it up and running and its welding great. The ark is allot rougher than my Lincoln powermig 140c but I was expecting that from some of the reviews I’ve read, it will just take some getting used to it I guess...

So I have one other question: When does the fan come on? I welded for maybe 2 min. the other day and it didn't kick on. Is it temp controlled?

[cruizer]

Fan - on - Demand. Heats up fan comes on, may not come on for an hour....

full load at 250 amps, it'll come on in 10 minutes,

[cruizer]

Arc isn't asl that rough, least it shouldn't be after the arc is started, likely you don't have it set correct

[big mike]

What I always heard was that the 250 did not have a "buttery" arc that the 200 or 251,252 has.

[cruizer]

Same arc as the 251, uses a set of SCR's as its rectifier. Only problem with the machine is the speed, as there isn't enough of it, though there is a fix for that, just can't remember which wire to move.

[woodtick007]

Same arc as the 251, uses a set of SCR's as its rectifier. Only problem with the machine is the speed, as there isn't enough of it, though there is a fix for that, just can't remember which wire to move.

I would be great to know the fix....If you remember it and don't want to post it send in a PM. It would be greatly appreciated