MillerMatic 251

[mudfreakk]

Hey ya'll I'm new here but not new to welding, I haven't welded in about 10 years so the new machines are a bit different than I'm used to. I just bought a MM251 got it all setup start welding running 75%Ar 25% CO2, when I strike and arc it will hold the arc for about 2-5 seconds then stop feeding the wire

The wire is not sticking and shorting out to the piece I'm welding, gas is flowing, tried different guns, Run out is set to 100.

Does anyone have any other Ideas as to what could be happening here?


Thanks,

Carl

[welder_one]

i have not seen this before but you might check that the liner is installed properly, the drive roll tension is right, the tension on the spool of wire and lastly, check your ground. i am grabbing for straws here. maybe someone with more experience with one of those machines will tell you what is wrong.

[tdkkart]

What does it do if you run wire on the floor for the same amount of time???

Could be it's sticking in the contact tip??

[mudfreakk]

Ground is good, tension is good, it curls the wire on wood. So in my past experience thats how it should be.

Now I have it wired from a 4 prong outlet to a 3 prong outlet. Putting the ground and neutral together on the 3 prong side.

[mudfreakk]

What does it do if you run wire on the floor for the same amount of time???

Could be it's sticking in the contact tip??

I can squeeze the trigger all night as long as its not making an arc

[SundownIII]

Mudfreakk,

Have a MM251 so I'll try to help out. First off, I assume you're using the M25 Gun with 12' lead.

What size and type wire are you using?

Have you checked the drive to see that it is attempting to push wire when you engage the trigger? Have you checked to insure the right wire groove on the drive rollers? The groove diameter for your size wire should be readable when looking at the drive roller.

If the drive roller is turning and wire is not coming out, you either need to increase the tension on the drive roller or reduce the tension on the wire spool (where the wire is stored).

If the wirefeed motor stops turning with the gun trigger still engaged, I suspect you have a faulty trigger switch (probably a loose wire).

Size/type wire, what you're welding, volts/wirespeed, stickout, would all help us help you get the problem solved.

Check those few things and let us know. There's a lot of guys on here with a lot of hours on the MM251's.

P.S. I picked up a Bernard Q300 gun (kept my M25 as a backup) and have "never" experienced a wire feed problem (knock on wood).

[mudfreakk]

I'm using the following:

The wire drive is pushing wire through the gun without and issue, it curls the wire on a piece of wood when I was setting the tension. Wire is in the correct groove.

tweco pro 250 gun as I'm not impressed with the m-25 trigger
.035 solid wire
stick out 3/8 - 1/2 inch

Welding 1/8" steel settings on the welder as follows
17.0 Volts
250 inches per minute on the wire feed
75%Ar 25%CO2 at approx 25 CFh

[dabar39]

Is it possible you have it wired wrong and only getting 110 to it instead of the 220. It may be enough to run the drive rollers but not enough to let it strike an arc. Something doesn't sound right about putting the neutral and ground together. Also what size breaker are you running?

[SundownIII]

Mudfreakk,

All your settings appear to be in line. You've already checked all the obvious things.

As Dave (Dabar) has indicated, sounds like the machine is not getting sufficient power feed to maintain an arc and wire feed combined.

The power cord that comes standard with the MM251 has two hot leads and a ground. The unit does not require a neutral. Have you tested the two legs providing power to insure that you are receiving approx 240V between the two legs? How did you make the transition from the four prong receptacle and the three prong plug on the MM251? Adapter/short cord?

Did you by chance notice a voltage drop (display) on the MM251 as the arc was struck? (know it's hard to hold an arc and view the display--helper may be in order).

Sounds as if you're getting the correct initial voltage but not enough amperage to maintain the arc/wirefeed. With all that said, I would look closely at the transition between the hardwired receptacle and the plug on the machine. I would just tape off the neutral wire rather than bonding it to the ground. Common practice in household wiring but a real no no around the water (dock wiring). In dock wiring you definitely do not want to show continuity between your neutral and ground wires or you will surely experience electrolysis.

Keep us posted.

[willy]

I would start by wiring it directly from the panel with the correct receptacle- you should not tie the nuetral and the ground together. On a service panel this would be OK but on a subpanel - not good....

[mudfreakk]

I have a 60amp plug on my house. I'm going to plug directly into that when I get home from work tomorrow night and see if there is a differance. I will rewire the plug and outlet to remove the neutral wire.

IF this works I will be putting a 60 amp circuit into my shed so I can use my welder.


The transition was done with a short cord, and its in the cord where the neutral and ground are together not the sub panel.


ya'll thanks for the help, I'll be bak tomorrow nite to tell of my findings.

[SignWave]

Mudfreak,
the 251 has no neutral. Its straight single pole 240 with a ground... red wire to red wire, black to black. green or bare to green or bare... nothing more nothing less.

if youve got a nuetral tied to ground in there somewhere that is absolutley wrong. you dont need to do anything to the cord cap (plug)on the welder , but you must install a 50A/240V receptacle on the feed side(from the panel)
Follow the scheme on the back of the receptacle. brass screws are for hot leads and the silver or green is for the ground. Leviton (probably Eagle in the USA) makes a good recpetalce as does cole hersey.

[mudfreakk]

Signwave,

Thats for the input, right now I have a 4 pole 60amp circuit that I'm using to test the welder. I was told by the wiring diagrams and also an electrician to hook the neutral and ground together on the end of the 3 pole receptical for the welder. Tonight I'm going to rewire it and leave out the neutral.


I'll let ya'll know, i ti works I will be putting a 60amp service in my shed.

[SignWave]

there is no such thing as 4 pole Mudfreakk. three pole yes, thats considered three phase power. in the panel you will have three live (red, black, & blue or A, B, & C conductors feeding the bus and a neutral(white) AND a ground wire(green or bare). The only point at which neutral should even come close to a ground wire is within the panel. At this point they may be bonded together as the case of the panel is at the same potential as the neutral. the theory is that if you twist the ground and neutral together at the device end and something on that machine or device shorts out to ground, you are potentially electrifying the neutral conductor which may or may not be attached to another device. this may lead to fire, damage or death. have you ever used a skill saw in the rain? its quite an electrifying experience. saw dust and water make a great electrolite soup and it will past current. Bin there .

Be careful man.

if you remove the neutral, make sure you cap it off. It has no other use in feeding power to you 251. do not use tape, use a large wire nut or "marret" then tape that nut on. All you need to power your 251 is a red wire and a black wire and a ground.
and again. be careful....SW

[jake]

have you checked your voltage jumper in the machine?