Ray,
I have 3 new 350P's but I'm sure we don't work em as hard as you do.
We did however have a miserable day right after installation. Our 350P would not short circuit, Not with CO2, Not with mixes... Very high ropy ridges... Tried everything I know, called out the Local Guru, he was frustrated nearly to profanity. He brought in a brand new power supply and It had the same trouble.
We took a break and really talked about what could be wrong and thought we had all the bases covered. When we returned to the lab, all the bad machines ran perfectly and we haven't had an off day since....
We never really got our brains around what caused the problem.... It almost acted like a gas issue but we really took some control precausitons to investigate that. If you are using manifolded gas, try rolling in a single bottle known to be clean and see if that does not provide a solution.
So with the exception of a couple of hours our 350P's are very good at traditional short circuiting.
Hello Ray, other than the gas suggestion that Lawrence mentioned. Is there any possibility of poor grounding or possibly single-phasing on the input power? I have an older CP 200, I know this isn't a 350MP, but occassionally when someone plugs it in they won't pay attention to getting the plug fully engaged and it won't be firing on all three phases, it won't weld worth a hoot. I have also on occassion seen one of the wires in the plug work itself loose and even though it appears to be connected, it isn't. As far as the input voltage goes I have had similar experiences, but here again not with the particular machine that you are having the issues with. In these cases the grid that we were hooked up to would have high-use issues and upon checking the input voltages we noticed drastic drops at particular times of the day, when these drops occured the arc characteristics of the machine went to hell in a hand basket. Of course the ground cable connections can be suspect sometimes, carefully check all of the connections and the clamp itself, particularly the spring. Sometimes I have seen internal corrosion issues where the ground cable has been crimped and although it appeared tight it had a lot of green smut and other visual indicators that were preventing good contact or causing intermittent contact of varying levels. Just some food for thought. Best regards, Allan
Thanks for the reply guys! I am using bottles on these machines so I'm pretty much ruling that out. Now that I think about it the symptoms are fairly similar to the characteristics of running on single phase. Maybe the switches on the machine are wrong. I know some of Millers new machines are designed to weld on single phase and three phase, but you have to have the switches right. I'm not even sure if the 350P has these switches for some will do it automatically. I will have the input power at the plug checked and make sure everything is good to go there as well.
As you face the machine, look to the lower RIGHT side pannel........ You should see a orange and black decal and window... It will show the power your machine is set to accept....
However if you are feeding the wrong power to the machine I would suspect you would get an error fault.
Owners manual provides instructions for adjustment for different power....
We had to adjust ours to 208 3 phase.
They will run on single or three phase... My guru says they perform better all around on three phase
I checked it out Lawrence and it's showing 460V in the window. The output power coming out of the wall is listed as 440V. I don't know how much this effects it.
Hello Ray, I believe the voltages are typically +/- 10%, meaning that you could have a roughly 46 volt difference either way in this particular application. Regards, Allan
I was looking at a used Airco Dip Pak 200, it welded like crap. I have one of these, and know how it should operate, and what the settings should be. It turns out that the guy had changed the service in the shop to 208 volts, but the machine was still set for 240. I expect that this was the problem, but someone out bid Me, so I never found out for sure.
So if our 440 is reading at the wall 10% low how will that effect the characteristics of the machine? I'm going to have the voltage read at the wall just to make sure, but I'm pretty sure were within limits. Never know though around here.;-)
I checked the volts at the wall and I was getting 2 different readings. I check at the outlet plug and if I went from ground to a + terminal I got like 255volts, but if I checked from 2 hot terminals I got 486 or so. They said our building is so old that we have a grounded phase in some sections of the plant. Would this change arc characteristics?
Thanks, Ray C.
A "grounded phase" would be a "short". Your 255v phase to ground and 486 phase to phase sounds like you have a 3 phase "Delta" service. If it is 3 phase, you would actually have 3 (three) hot wires.
Griff
There can be different voltage on each of the phases due to single phase loads drawn from the phases individually being poorly ballanced. as more load is placed on one phase relative to the others the voltage becomes lower. If this is the problem, it can be inconsistant. Motors seem to tolerate these differences pretty well, but I would suspect that more sophisticated equipment may have greater issues with the imballance. If a midpoint grounded delta phase is used to suply lower voltage [230 from a 460 service or 115 from a 230 service] things can get even further out of wack.
You can get 115v from a 230v service single phase but one phase to ground from a 460v ^ service is not going to be 230v.
You are correct that unbalanced loading between phases can cause problems.
Griff
Hi Ray,
A few of the folks that I work with have the Miller 350MP. They primarily use it for MIG aluminum and every now and again for FCAW or GMAW of carbon steel. They have different guns for the Al and CS btw. The love the machine after they got over their own learning curves using the control panel mostly, a push-pull gun and just getting familiar with the machine.
When I helped them set it up (the Miller and sales rep wouldn't help them out) we initially had some issues with GMAW aluminum both pulsing and straight; however, the pulse problem was due to the welder not setting the machine properly and on the straight GMAW we were getting a fine spatter and smut at the toes of the welds, which we got rid of by adjusting the amperage, voltage and by changing the liner. Haven't tried GMAW; however, we were able to tweak the FCAW with a 75/25 shielding gas with no significant problems. Haven't tried GMAW with CS though.... If you've tried following the troubleshooting section on the back of the manual and it hasn't helped I'd call the Miller guy, although hopefully you get better support than we do here in Atlantic Canada!
Which leads to a question - did you guys look at the Lincoln Power Mig 355MP before you bought your Miller? One of the guys I know with the 350MP are looking at a new 350MP or the Lincoln Power Mig (cuz of its bells and whistles). Anyone have any thoughts on this?
Sean
We probably did not look at the Lincoln 350mp's before we went with Miller. Miller is pretty close to our plant so they're usually pretty good about coming over and keeping us up and running which is pretty fortunate. I'm going to get a hold of Lawrence's miller contact today so we'll see what he has to say. Thanks, Dave for the phase lesson and you to Sean for taking the time to help me out! Man you're always learning something around here.;-)
Topic Welding Industry / General Welding Discussion / Millermatic 350P arc characteristics on straight MIG mode.
