240v/50a Welder Problem.

By running too hot do you mean the welder gets hot when running or the settings you are using are giving you more heat in the weld than required for the steel you are welding?

The chart with recommended settings that come on the welder are only a rough starting point. Most welders that I've used seem to have settings that are "colder" than I like but my current miller mig welder's recommended settings are usually a little hot. If you can adjust the welder to get a good weld I don't think the welder is bad, just the chart. Make your own chart that you can jot down the setting that worked best for a given joint and steel thickness. This will eventually get you a chart that works for both you and your welder and will give you the best results.
 
sanddan,
Yes the welds seemed hot not the machine. I agree with you, But I was way off and many of the reviews for this machine put it as right there on the auto settings. My concern was not whether or not the machine would weld good or not. Rather was something wrong with my power or with the machine.
My thoughts now are that there is more than one cause to my problem(not really a problem more power on the welder is good) First I think the fact that I am on a good circuit, with 245v is letting the machine perform at it's best. second I weld a bit cooler than a lot of people (like a little more puddle controle) And last the welder may have been set up to suit new welders who would weld hot and fast beads.
But as best I can tell the machine and my power are OK.

Mark
 
Ok, you do NOT have a power issue. The way an inverter welder works is the AC line comes into the unit, is rectified into DC first thing. The inverter circuits then chop up the DC oddly making it AC again but at a higher frequency. It's then rectified again and sent to the torch. The way it's regulated is the control circuits look at the output voltage and vary the dwell time of the inverter circuit. Since you are running an output voltage of 20 to 30 volts constantly (and the current varies) and the input lines are at 240 volts, the voltage drop would need to be really significant for it to loose control of the voltage and it change at the output. This is how an inverter welder can run at 208 /220/ 240 /480 /575 on 1 or 3 phase and either not need switched or only require a switch be flipped to change the input voltage. The old transformer powered units that used high current SCR outputs with a rheostat to set their output voltage were susceptible to voltage variations on the power line. Inverter technology or ANY quality does not have these issues.

Now your issue.
Your gas distributor is to blame. The tank you have was filled with some other gas before and didn't get purged correctly when it was refilled.
Most common MIG gas is a 75/25 mix of Argon and CO2. There are specific tri-mix gasses out there that have helium, oxygen and some other gasses that will have an additional heating effect on the weld. If the tank is full of a gas like that, it will do what you are talking about. If the tank contained some level of one of those gasses, specifically oxygen and was relabeled to be 75/25 and not purged right, again you will effectively have the same issue.
Take your tank to a buddies with a place with a MIG welder and hook it to his unit and try welding with it. Or just take it back and get a new tank and tell them the gas you got is contaminated. I worked on a MIG unit that was welding so hot that it would melt down the MIG tip and turn the gas cup orange when you welded with it. Voltages and currents were all correct. We were welding on 1/2 plate so the heat wasn't effecting the weld that much but it didn't look exactly right. The guy finally said that it started when he changed the tank out. We put a new tank on along with a time and cup and the welder was fine again. Gas contamination does happen. 1% oxygen mix is used for smaller welders to run heavy plate that they can't handle running just 75/25. If you got a high contamination of O2 or helium like we had, it would really heat things up.

I assume that you used the same gas for both welders and had similar results.
I assume that you are also using the same wire in both machines.
Bear something in mind with wire as it applies to building race cars. You are working on parts of a 50 to 100K dollar car.
The parts that you are welding are there to save the life of the driver in the event of an accident.
Are you sure that the bargain basement roll of coat hanger wire crap that was half the price of the next closest wire a good idea to be welding with.

I often wondered why my TIG welds were always black and smoky looking. I prepped correctly, I used sufficient gas and still I got dark welds.
When I finally started buying the TIG rod that wasn't the cheapest copper clad crap on the shelf, the welds began looking right.
 
Keith, while you make a valid point, and I appreciate your help. There is no gas, I am welding FCAW not GMAW. The rest of the post about the inverter was helpful and very interesting. I agree on the wire, I use either Lincoln or Radnor. Both ran about the same.

Please take any replies over to this forum as the mods already said we have gone off topic. Electric to welding.
http://www.hobby-machinist.com/threads/eastwood-mig-250.39699/page-2#post-351250

Mark
 
120/240 is nominal voltage...that is to say it can fluctuate depending on many variables between the power distribution lines through the transformer to your house. If you checked 100 different houses/garages you would be surprised to find that the 120/240 volt that we all know are not exact. The minimal voltage differences you mentioned are just that, minimal. They would have no impact on the welder. Too hot...turn down.
F.Y.I The general rule of thumb for motors is to keep them within +/- 10% of the nameplate rated voltage.
 
toolman147 said:
120/240 is nominal voltage...that is to say it can fluctuate depending on many variables between the power distribution lines through the transformer to your house. If you checked 100 different houses/garages you would be surprised to find that the 120/240 volt that we all know are not exact. The minimal voltage differences you mentioned are just that, minimal. They would have no impact on the welder. Too hot...turn down.
F.Y.I The general rule of thumb for motors is to keep them within +/- 10% of the nameplate rated voltage.
Click to expand...

Agree 100%. I also want to add that the commentary about using 6AWG for a welder is likely overkill unless the welder is rated for 100% duty cycle at the top end. Many welders can use 12AWG or 10AWG wire for their 50 amp circuit, especially the lower end hobbyist ones with 20%-50% duty cycles at full amperage.

This is because the wire never has a chance to heatup. You weld for 2 minutes, then spend 2 minutes grinding and fitting up for the next weld...unless you are me, then you weld for 2 minutes and grind for 20, but I digress.

Take a look at article 630 in the NEC if you are bored.
 
When it comes to wire sizing...The breaker size MUST be considered. If your going to run a 50A circuit with a 50A breaker then #6 wire MUST be used. If, for some reason, you want to downsize the required circuit size (amperage), then you must also downsize the breaker to match the amperage rating of the conductor (wire). You can use a smaller breaker on larger wire, but, NOT a larger breaker on smaller wire.
#14=15A
#12=20A
#10=30A
#8=40A
#6=50A
 
It's always better to play it safe when installing a receptacle circuit. Article 630 allows for some exceptions for welders, however if the welder in question uses a standard 50A plug, then the receptacle would have to match (50A) and therefore a device that would draw more could be plugged into it, so the conductor (wire) and breaker would have to be sized accordingly. Even in a home shop/garage where usually it wouldn't be an issue, there may be a future device purchase that would need the 50A circuit, so why not just run the complete 50A circuit the first time and be done, allowing for any future needs.
 
toolman147 said:
When it comes to wire sizing...The breaker size MUST be considered. If your going to run a 50A circuit with a 50A breaker then #6 wire MUST be used. If, for some reason, you want to downsize the required circuit size (amperage), then you must also downsize the breaker to match the amperage rating of the conductor (wire). You can use a smaller breaker on larger wire, but, NOT a larger breaker on smaller wire.
#14=15A
#12=20A
#10=30A
#8=40A
#6=50A
Click to expand...

Yes, the breaker size must be considered but you cannot make sweeping generalizations such as the above. There are many exceptions to having a breaker larger than the norm for a given wire gauge, and they include motors, welders, air conditioners, etc. The proper wire size is determined based on the required AMPACITY of the circuit. The required ampacity can be adjusted up for things like continuous duty applications, and can also be adjusted down for things like welders where they have limited duty cycles.

The breaker may exceed the ampacity of the circuit in many situations, but not in many others. They are 2 different calculations and often are not equal.

Your standard amperages above are also incorrect for many situations and are really only correct for Romex, and SER cable (when in contact with insualtion etc). #8 Can go to 50A and #6 65A when using MC, or THHN in pipe, or some other situations.

toolman147 said:
It's always better to play it safe when installing a receptacle circuit. Article 630 allows for some exceptions for welders, however if the welder in question uses a standard 50A plug, then the receptacle would have to match (50A) and therefore a device that would draw more could be plugged into it, so the conductor (wire) and breaker would have to be sized accordingly. Even in a home shop/garage where usually it wouldn't be an issue, there may be a future device purchase that would need the 50A circuit, so why not just run the complete 50A circuit the first time and be done, allowing for any future needs.
Click to expand...

I won't argue with you here...it is always better to deploy a circuit using a wire size that matches, but that can get very expensive. In a shop where we might want 2-3 50A welding outlets so you can have the outlet near the gear, you can get into serious money real quick, chew up panel space quickly with large wire sizes, fill up conduit etc, all for a device that runs at 20% duty cycle? Not sure it is worth it to me.

While the code does not require it, it is accepted best practice to label welding outlets that use wire that is smaller than normal as allowed in article 630 with 'FOR WELDER USE ONLY'. I also label it with the circuit ampacity as well, since when you mix and match welders one may have a larger duty cycle than the other.
 
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Yes, you are correct on the exceptions for specific equipment...But I guess it was my mistake for assuming the original question was based on a home Garage/Shop scenario, where the person wasn't that well versed on the specifics of the NEC and would use the most common conductors available such as 6/3 romex... I should have known better than "assume" anything.
I totally agree that in a commercial shop where multiple Welders are used it would make more economic sense to wire them accordingly. In a home shop where one receptacle may be used for a few different pieces of equipment, one 50A receptacle with #6 wire would be able to safely handle them.
My Bad.
 
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