120v MIG 3/8" coupon test results

[ThomasH]

Would those who are adamantly opposed to using a 120v welder on 3/8" plate also be negative on using a 240V welder on 3/4" plate? Is the energy delivered (and required) not directly proportional? Seems to me it is more about proper weld design, preparation, beveling and number of passes than voltage.

Ummm, 120 volts at 20 amps max is not 1/2 of 240 volts at 50 amps...

I use .045 lincoln dual shield with my miller gear on a 50amp/240 volt circuit, and have welded 3/4" material a number of times. There is a large difference in spray arc versus short circuit MIG. It takes 300+ amps to do spray arc on 3/4" and thicker material and I get excellent penetration.

 

[Arc weld]

The only thing in this thread that has me thinking is the statement about using a bigger breaker to supply the welder with more amps, and would it allow more output at the business end of the welder. I dont know, so am asking if its possible.

With that said, I was trying to tig some 3/8 aluminum with my 220v 250 amp machine the other day. I have a 60amp fuse (yep, I said fuse), in my panel, actually 2 big fuses, about 1in dia and 6inches long, at $17 each. While trying to tig the aluminum, with machine set on 250amps, I blew one of the fuses. Installed another fuse and blew it too. Pretty sure the machine is supposed to be fused at 60amp and darn sure the machine was at max capacity. Recommended amp for 3/8 aluminum tig weld is 230-260 amps, so I was at the limits for my machine, kind of like the 120migs on 3/8 steel. Not sure I would want to use a bigger fuse to power the welder, in fact, I plan on a whole new breaker panel installation next wkend. Still, I wonder if using a bigger breaker than 60amp would or would not damage my machine, and I plan on dragging the welder out from the wall and checking the panel on the back to see if the machine is indeed supposed to be wired to a 60amp breaker or fuse, or if maybe it might suppose to have a even bigger power supply. Machine is a idealarc 250/250 stick tig with high fre start.

I should probably also note that I am a beginner tig welder and just happen to have a aluminum spindle housing off a lawn mower that was really beyond repair, and I just wanted to know if I could weld it using tig, just for practice. I realize my welder, even tho it is a 220v machine would be pushing the limits for tig welding 3/8 aluminum and I aint beyond paying someone with the right equipment to weld a job I am not equipped to do myself. I think thats something some of the guys that want to keep pushing the limits of their 110v migs should take into consideration.

A bigger fuse won't hurt the machine. An Idealarc 250 will shut down if it gets too hot. Power factor capacitors were available too. Now if a 120 volt MIG draws 38 amps, then you'd probably want an even bigger breaker than a 20 amp. Wouldn't you also need larger wiring to safely handle the additional amps? If that's the case it might not be any cheaper than just wiring in a proper 220 volt plug. Both Lincoln and Miller caution that 120 volt MIG welders shouldn't be pushed past their limits. We now have several very clear examples why they stress this. If the two biggest names in welding with over 200 years experience don't know what they're talking about, we're in big trouble. There's always gamblers anonymous.

 

[IslandTractor]

Ummm, 120 volts at 20 amps max is not 1/2 of 240 volts at 50 amps... I use .045 lincoln dual shield with my miller gear on a 50amp/240 volt circuit, and have welded 3/4" material a number of times. There is a large difference in spray arc versus short circuit MIG. It takes 300+ amps to do spray arc on 3/4" and thicker material and I get excellent penetration.

Why is 120v capped at 20amps? A dual voltage welder can handle much more.

 

[Blade Breaker]

Why is 120v capped at 20amps? A dual voltage welder can handle much more.

I would think it is due to the supply circuit ratings? Most shops have 20 amp breakers.

 

[aczlan]

I would think it is due to the supply circuit ratings? Most shops have 20 amp breakers.

Pretty much. Outside of the RV world, a 120v circuit over 20 amps is rare as you can use a 240v circuit and get the same power with lighter wire (ie: a 120v 40 amp circuit has the same amount of power available as a 240v 20 amp circuit but the 120v circuit needs 8 gauge wire while the 240v circuit only needs 12 gauge wire).

Aaron Z

 

[MossRoad]

Pretty much. Outside of the RV world, a 120v circuit over 20 amps is rare as you can use a 240v circuit and get the same power with lighter wire (ie: a 120v 40 amp circuit has the same amount of power available as a 240v 20 amp circuit but the 120v circuit needs 8 gauge wire while the 240v circuit only needs 12 gauge wire).

Aaron Z

Since its not welding related, I'll quickly bow back in.....

 

[IslandTractor]

Since its not welding related, I'll quickly bow back in..... YouTube Link: https://www.youtube.com/watch?v=iX3kxAA2L4Q

I gotta get me one of those 221 welders.

 

[IslandTractor]

Pretty much. Outside of the RV world, a 120v circuit over 20 amps is rare as you can use a 240v circuit and get the same power with lighter wire (ie: a 120v 40 amp circuit has the same amount of power available as a 240v 20 amp circuit but the 120v circuit needs 8 gauge wire while the 240v circuit only needs 12 gauge wire). Aaron Z

As a practical matter, that makes a lot of sense especially in a residential setting. However, many (?most) generators have a 120/240 circuit that puts out 30 amps of 120. Wouldn't a dual voltage welder like a Miller Passport or Multimatic be able to use all 30 amps at 120v? (Let's assume for the moment that the dog ate the 240v adapter plug but a dogbone adapter allows us to plug the welder into the 120 circuit). This would also apply to marinas and RV parks.

 

[JimRB]

I would imagine that a welder manufacturer designs a machine based on what most people have available. No idea about the dual voltage machines. The 120 volt machines sometimes are rated at 120v 20 amp circuit. I was looking at Hobart specs for their current Handler 140 and it stated 20 amp circuit. Some may be rated at a 15 amp circuit. In any event it is not normal to wire a residential or even industrial or commercial 120 volt receptacle circuit with larger than a 12 gauge wire. I would suspect that most houses in the USA have their circuits done in 14 gauge 15 amp circuits. To wire in 12 gauge is more expensive wire that is a little harder to work with inside the boxes. 20 amp receptacles also cost a bit more than 15 amp receptacles but are not required on a 20 amp circuit in some instances. 20 Amp Receptacles? - Electrical - DIY Chatroom Home Improvement Forum

When I wired my house I had in my mind that you save a tiny bit of electricity using 12 gauge wire versus 14 gauge. Something I saw at a trade show. I suspect it was the wire manufacturers trying to sell more copper. See the last paragraph. Electrical: Building Wire - Bigger Really Is Better

Reminder to those who forgot, fuses and breakers are installed to protect the wiring. You do not install larger breakers or fuses because you keep popping them. Of course if someone installed a too small breaker or fuse on a circuit and you are positive that the wire from protection device to receptacle is properly rated then you might be able to up size the breaker or fuse.

Wire size chart with no length of run factors. NM is non metallic (romex) and UF is underground feed (grey romex where I live) Ampacity Charts

 

[Mark @ Everlast]

I would imagine that a welder manufacturer designs a machine based on what most people have available. No idea about the dual voltage machines. The 120 volt machines sometimes are rated at 120v 20 amp circuit. I was looking at Hobart specs for their current Handler 140 and it stated 20 amp circuit. Some may be rated at a 15 amp circuit. In any event it is not normal to wire a residential or even industrial or commercial 120 volt receptacle circuit with larger than a 12 gauge wire. I would suspect that most houses in the USA have their circuits done in 14 gauge 15 amp circuits. To wire in 12 gauge is more expensive wire that is a little harder to work with inside the boxes. 20 amp receptacles also cost a bit more than 15 amp receptacles but are not required on a 20 amp circuit in some instances. 20 Amp Receptacles? - Electrical - DIY Chatroom Home Improvement Forum

When I wired my house I had in my mind that you save a tiny bit of electricity using 12 gauge wire versus 14 gauge. Something I saw at a trade show. I suspect it was the wire manufacturers trying to sell more copper. See the last paragraph. Electrical: Building Wire - Bigger Really Is Better

Reminder to those who forgot, fuses and breakers are installed to protect the wiring. You do not install larger breakers or fuses because you keep popping them. Of course if someone installed a too small breaker or fuse on a circuit and you are positive that the wire from protection device to receptacle is properly rated then you might be able to up size the breaker or fuse.

Wire size chart with no length of run factors. NM is non metallic (romex) and UF is underground feed (grey romex where I live) Ampacity Charts

Jim, it would be normal that you would think that. But that would not be the case. To get to the bottom of the matter, you must read the fine print.
Hobart (and Miller and Lincoln etc.) small MIGs give their input rating at their rated output. The rated output is usually the number that looks the most "appealing" for marketing purposes. If you look carefully it states amps input at rated output. Rated output is 90 amps @ 20% duty cycle. Yet, the company states maximum output is at 140 amps. That's a far cry from 90 amps and requires a lot more amps input. The other factor is the relatively new way they state input ratings and that the old way is still allowed. The "preferred" way is to state the I1Max and the I1EFF currents. I am not an electrician and my understanding may not be perfect or accurate in all respects. However, I do try to stay on top of these things. Many welding companies are still using the older way which can muddy the picture somewhat. The I1Max method allows you to properly size breaker, and then the wiring separately. The I1max accounts for the maximum inrush experienced at start up. The I1EFF is the rated effective current draw. Here's a link discussing this for welders:Page 70-537

There are some units we offer and other companies such as Miller offer with inrush ratings of 40 amps or more on 120V for maximum output. They do a good job disguising this, however. They 120V input rating for a Dynasty 200DX is 31 amps (stick operation) @ 60% duty cycle which is only 100 amps output. The machine is rated for up to 200 amps on 120V! Then there is a disclaimer that the units are limited by duty cycle due to input cord sizing. That gets confusing for sure.

To sum it up, no input/output ratings have little to do with what someone might have. The numbers are manipulated by mfgr's in such a way that it makes a person see and think that 140 amps are certainly capable...but then in the fine print show 90 amps output at 20 amps input...and even less on 15 amps input around 70 -75 amps. People think 140, but have no idea they are playing around usually about half that.