After discussing the issue of needing a small portable welder in my truck and doing some welding with an elderly Marquette 110vt transformer buzzbox, Ernie Ls suggestion of finding a small 110vt inverter welder makes a lot of sense. My Lincoln Weldpak 100 is not suitable for a lot of the field welding I need to do, is just not big enough..sigh..damnit
Anyone got a 110vt inverter stick welder they want to swap for something?
Gunner
"Deep in her heart, every moslem woman yearns to show us her t*ts" John Griffin
Gunner, do some math and you will see that the 15A breaker will trip way below any usable welding parameters are reached. My calculations suggest that at 36 volts welding voltage, and 50 amps of welding current, your power consumption at the electrode tip reaches what a
15A breaker can supply. And that's before taking conversion losses into account.
i
The HF stick/TIG unit is out there, less than a couple of hundred on sale with coupons. Downside is that you have to use really, REALLY small rod and duty cycle is pretty low. It IS light, though. OK for sheet metal patching, just don't plan on building cars with it. I think you'll find that most of the 115-only inverter boxes are going to have the same limitations, you just can't pull enough juice out of a household 115v circuit to do heavy work.
Unusual for the arc voltage to be much above 20v when actually welding. So 20 volt x 100 amps = 2 KW. Now that is an easy load for a normal domestic socket here in the UK where we can draw up to 3 KW, but I don't know the idiosyncrasies of the US electrical system to comment if that's ok on your side of the pond.
I have done some engineering jobs that involve operating equipment off the power systems of several countries and the British system, as best I understand it, is unique. In the U.S., and in virtually all other countries, a circuit is fed from a fuse or breaker with the line going from one outlet to the next to, finally, one at the end of the string. In the British system, the line is a loop from fuse to outlet to outlet, etc., and then back to the fuse. In other words, the circuit is fed from both ends. Hence, a common house circuit using AWG 14 wire is, in the U.S., fused at 15 amps, but in Britain, fused at 30 amps. Each outlet is, in effect, fed by two AWG 14 wires in parallel. And, to protect the device plugged into it, the plugs contain fuses appropriate to the device being plugged in. So, you can take 3 KW off of a British outlet, but only half that off one on this side of the pond. And, before someone else feels the need to point it out, in the U.S., kitchens and most shops are wired with AWG 12 and fused at 20 amps...
Also of course not only is our current capacity doubled, but so is the voltage as our sockets are all 230v, so 4 times the capacity of American 110v ones. I reckon that it is a good well engineered technical solution.
Now to electrical matters: inverter welders can do more with the same supply current than transformer CC (stick or TIG) welders can because they can run at much closer to unity power factor. They need not rely on inductance (loosely-coupled xfmr) to produce acceptable open-circuit voltage for arc start followed by current limiting to the arc because they use electronics to accomplish the required control. Arc voltage at 100+ amps with appropriately-sized rod is nowhere near
36 volts, more like less than 24. Use a 20-amp breaker and substantial line cord. 20-amp breakers can handle more than 20 amps for short periods. The little boxes have limited dutycycle at 100+ amps, but they'll do the job if you're not in a hurry and can live with a minute or so of continuous arc time followed by 8 to 10 minute cooloff periods.
Transformer-based small wirefeed boxes e.g. Linc SP135+ (135 amps max) can deliver 100+ amps because they don't need high open-circuit voltage for arc start. They are constant-voltage machines. They still have limited dutycycle. They're easily capable of soundly welding 3/16" steel with fluxcore, well over 1/4" in the hands of a skilled weldor though it's very slow going.
It's very true that there's not a lot of power available for a standard
115V 15 Amp circuit. But standard circuit breakers all have a time deal feature that allows you to pull extra current for a short period of time before they trip. I tried to find some real trip curve graphs of typical home circuit breakers but the sqaured ecatalog site seemed to be down and the GE site seemed to only have them in autocad format.
But I think it's typical to be able to run a breaker at about 50% over rating for up to about 60 seconds. Or something like 2 minutes at 25% over rating. And maybe 30 seconds at 2x the rating. It needs something like 8x the current to blow instantly. But these times could be high. These numbers might only fit special long delay breakers and the periods might be shorter for typical home breakers.
Arc welders that run off 110 volts are pushing these numbers to the limits to get as much short term welding current out of these small boxes as possible. They already have low duty cycles at their highest ratings.
The Miller Maxstar 150 S for example is an inverter that runs on 115 or
230V. On the spec sheet, you can see the max voltage/current output curve for 115 volt operation has a peek that looks to be around 160 amps at 15 volts. That's 2400 watts. The spec sheet also lists a 35% duty cycle for
115 V use at 100 amps and 24 V, which is also 2400 watts of output. And it lists a 26 amp input.
115 volts at 15 amps is only 1725 watts. Even 115 at 20 amps is only 2300 watts. So the welder is clearly trying to suck higher wattage (amps) out of the wall for short terms by taking advantage of the trip delay that exists in the circuit breakers (or just trusting the welder will not try to operate the box on the higher current settings if they are using a 15A outlet).
I don't know if these type of welders force the limits on you when you run them at 115 instead of 230, but I assume some don't. The duty cycle chart limits it to 100 amps. but the grab shows it able to do 160 amps at 115 volts. So if you crank the think all the way up, you can probably get more out of them for very short periods without blowing fuses. But you will probably be faced with very small duty cycles because of the limits of the breaker. (weld for 10 seconds, wait a few minutes).
Of course, if you can run them off of 20 amp or 30 amp circuits at 115 volt then things will be better and you will be faced only with the duty cycle of the welder and not the duty cycle of the circuit breaker.
I have no welding experience with any of this, but just wanted to share my knowledge about how circuit breakers work. Since you can push them way over their rated limit for short periods, you can get more welding power of a 115V 15A circuit than you might expect for short periods.
Before posting the above, I just ran upstairs and did a test using two hair dryers pulling over 12 amps each on a 15 amp home circuit. They ran for over a minute and then the breaker on the power strip I was using tripped (I didn't even realize the strip had a breaker on it when I started the test). I reset the power strip breaker and it ran for another 45 seconds and tripped again. Still hadn't tripped the 15 amp house breaker. I felt that was enough testing. :) So there's a test running 25 amps on a 15 amp circuit for a couple of minutes without having the house breaker trip. That was about 3000 watts or the same power as 83 amps at 36 volts or 200 amps at 15 volts.
It makes things a lot easier for higher power applications like welding or high power tools. That's for sure. I envy what the UK and AUS folks have by default. We have to run special 220 circuits for all these high power tools.
I suspect you would want something like the Miller Maxstar
150. See:
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Pricey (Base model $818). A friend of mines shop got a couple of the Lincoln welders that compete with this and he thought they were great. They work best when fed by 230 vac though.
You could make up a special extension cord for your own use. You need two heavy 110 volt cords, a junction box and a 220 volt plug to fit your welder. You can put the 220 volt plug in the junction box or on a pigtail coming from it. Wire it up so the hot leg from each 110 volt cord go to the 220 volt plugs hots. Now when you go to use it you have to find two
110 volt circuits that are on opposite legs. This will give you 220 volt to the welder for TEMPORARY use. The electrician jockeys will wince, but I think you are smart enough to understand what is going on here and the consequences that could come from misusing it :)
What brought this whole thing on was from a week or so ago, when I had to weld some bits back on a "wrought iron" gate at a clients house. All I had was the Weldpak 100,..with .035 flux core, a long skinny extension cord and some wind. If Id had my normal 50' 10 ga extension cord, Id have been in much better shape, but while the welds were better than "putty welds" and were enough to hold the bits back on...cosmetically they sucked the big weinie. First mistake was welding vertical down hand...and running out of power, even cranked up balls to the wall in amps. The bits were 3/16"-1/4" that needed welding to 3" square tubing. Standard fence materials for the artzyfartzy clone tract housing.
The original welder was a good burger flipper. Poor welds, even poorer engineering..putting welds in the wrong orientation for the stress directions, only welding one side ..etc.
Nice family from Sri Lanka, the poppa owns half a machine shop where Id just torn down, repaired and put back together a 6' radial arm drill. So I was obligated to give it my best shot. I normally use the lil MIG for repairing guarding, the odd bench and shelf repair..minor welding stuff in the course of my duties as a machine tool repair tech...somebody let the guard on a belt sander get loose, vibrate then crack in half..so Id drag in the Weldpack, fix em up and add it to the bill. Works great for this sort of thing. Anything bigger, Id drag home, and weld it with "real" welding gear..and charge appropriately.
I simply could not get enough power at the wire to get a good looking fillet. The welder would run a nice bead for 20 seconds...then start bogging down, arc would sputter..etc. Felt like a bad liner feels. Never did trip the breaker in the house..so I knew I was losing something in the skinny extension cord, etc
Ernie suggested a inverter stick welder, for several very good reasons, the least being that stick tends to be "hotter" and give me a better weld, both cosmetically and in penetration. 1/16 and 3/32, of which Ive got probably 100lbs of 6011 and 6013 in those sizes..more 3/32. Good stuff, both Lincoln and Certainium.
Ive a very elderly Marguette 3 tap buzz box. 110vt, ac only, transformer with no chokes, inductors etc. Just a transformer inside sheetmetal with a ground clamp and a stinger. So I fired it up, and made some welds in the same sorts of materials that I was having fits with at the clients place. IRRC..30vts open circuit. Had some arc starting issues because of the low voltage, and had to work really short arc..but too short would snuff the arc, then turn the rod red hot instantly. So low voltage indeed. But it would dig pretty deep, particularly with 6011, did some welds, cut them and checked for penetration, etc. Then duplicated them with the Weldpack 100. Much prettier welds, but not as deep by a significant amount. I even ran a couple sticks of 7018, which did pretty good as long as I kept the rod in the puddle..but not too deep or it would also instantly snuff the arc. Could barely run it vertically though, either up or down..and restarting the arc was a stone bitch.
3/32"
But it showed me that I could weld thicker stuff than I could with the MIG. Not as pretty, not as handy and no where as convient as wire..but it worked well enough to try to find one, for these odd jobs.
Im not going to be welding very much with it, nor very often..but like particular tools..they save the day on occasions. The lil buzz box had three taps, low, medium and high..and the data plate on the box claims
90 amps maximum, with 30volts open circuit. And on High..I was running a full rod+ before it would pop a 20 amp breaker
If I had the room, Id have a small engine driven welder mounted in the truck..but I dont..shrug..compact and light is a requirement.
Im not..I repeat NOT a weldor. Im at best..a gifted dauber, at worst..a good burger flipper. Shrug. But stuff generally passes the BFH test. Stick Ive been doing for a few years, here and there..shrug
So thats why Ive been looking for a small compact 110vt stick welder to stuff in the back of the truck next to the Weldpack 100. Next to my 50'
10ga extension cord. Most cases..I wont have the opportunity to break into a sub and snag off 220 or 110. If I did..Id pick up a small but higher amperage 220 MIG. I figure a 135 would be about right. Nor do I have the room to load up my 5000 watt genset, "just in case"
Lincoln SA-200s and 300s are a dime a dozen where I live..but I cant pull a trailer around with one of the big bastards on it..just in case.
Thanks for the input.
Gunner
"Deep in her heart, every moslem woman yearns to show us her t*ts" John Griffin
The best solution would've been to put off welding until you came back with the proper extension cord. An alternative could've been to drill some holes and drive in some self tapping screws for a temporary repair, until you were passing by the next time with the correct cord.
Those small parts shouldn't have been difficult to weld with your little welder. Trying to weld with a line voltage drop at high power was most of (if not the entire) problem. Having some .030" FC wire might've worked better.
As Ernie has pointed out numerous times in RCM and SEJW, the highest output of these little welders is 90A (the better brands, not the elcheapos).
I also read a post regarding Ernie welding 1" steel demonstration workpieces (although not with FC wire, IIRC), so there is a lot of BS floating around concerning the limited thickness of steel that can be welded with the small welders (not that I'd feel comfortable about welding 1" steel with my 120VAC wire welder).
I'd be more confident in a 90A DC wire welder being the more versatile tool, compared to the little Marquette 90A AC stick welder. I would think that 90A of DC and FC wire would perform better than 90A of AC trying to burn 1/16" rods. The FC wire isn't all filler, since the center is flux.
Gunner, for these incidental welds you could go back in time and use oxy / acet setup and produce very strong welds with a little patience. I'll be you already have a small portable set on your truck
With great and due respect to Ernie re welding, I strongly doubt this assertion if it was made re 110-volt wirefeed boxes. It may have been made in context omitted here and it is probably true of 110-volt transformer stickwelders found at J.C. Whitney et al.
Perhaps you should. O/A can weld, isn't limited to cutting at all nor is it limited to small work in steel or aluminum. A lot of O/A welding was done in WWII by women working on the home front building aluminum airframes and various other weldments.
Material cost per weld (gas cost)is higher than stick or fluxcore wire, particularly with small bottles, but it works anywhere a truck can go.
Good gas welding requires more skill than jabbing a stick or running a wirefeed, but it's not that hard to learn. Folks (mostly women) with no previous experience learned to do it well during WWII.
If I hadn't read Ernie's numerous posts about the output of 120VAC wire welders, I wouldn't have been sure about referencing my comments specifically to Ernie.
The comments are sensible, when considering that most home/hobby 120VAC wire welders are connected to 20A circuits.
Transformer characteristics will allow increased current from the secondary windings, as the input voltage is reduced (approximately 1/5 th) to a working secondary voltage of about 20V (about 30V open circuit). I wouldn't expect the output current to be greater than 5x the available input current, and there would need to be conciderations for efficiency losses. I'm not an EE, so I just might not understand how output current could be 6-7x greater than the input current.
Welder manufacturers can use any numbers they want for model numbers, and Hobart chose to use 135 for the model I purchased. Another 120VAC unit I have (a Century), clearly states that it's rated output is 90A when connected to a 20A circuit (but also states that the maximum output is 110A switched to high range, when connected to a 30A circuit).
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