Scored a welder. Is it any good?

[Transit]

Just bought a used Airco 225 amp arc welder. $60 total with a package of 6011 rods. Decided on the stick welder because I'll be outdoors and didn't think a mig would work with the wind and such. Anyway, I've been unable to find any information about this welder on line. On the front it says HD-1 for the style. And it has the word "Stinger" on the panel as well. 2 rod jacks for high and low amperage. I'd like to find a manual and source for parts. When I turn the amp adjust the indicator gauge does not move so something is broke in there. To hook it up will 8 guage wire be big enough or do I need to go to 6? Sucker sure is heavy.

Join the Welding Web Forum if you have welding issues.

 

[patrick_g]

But, the question I have never got a straight answer to is why wires are rated in amperage and not watts??? Maybe theres an electrical engineer on here who could help us out.

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Because watts delivered to the load do not only depend on the ampacity of the wire. The wire has a few ratings of interest to this discussion.

1. highest allowed voltage for the insulation to remain safe at the highest rated temperature.

2. staying within the limit in #1 above amps is what counts in sizing wire and only derivatively does watts delivered matter.

First the equations needed to make sense out of simple electrical stuff:

I = E / R ___ where:

I = current in amps,
E = electromotive force in Volts, and
R = resistance in ohms

P = I * E Power in watts is equal to the current in amps times the voltage.

Example: If you were to use 600 volts to power a circuit wired with a wire safely able to carry up to 40 amps you could deliver up to 24,000 watts.

Using the same wire with 12 volts you could safely deliver up to 480 watts.

The folks making and the folks selling the wire have no clue what voltage you will use. It makes sense that they tell you the amp capacity of the wire.
+++++++++++++++++++++++++++++++++++++

It is my understanding of electricity that watts are what does the work/creates the heat. Wires are rated on how much current they can carry without getting to hot. Heat being the limiting factor. They have to stay under a certain temp to keep the insulation intact. Watts are what creates the heat. More watts =more heat.

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That is totally correct
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The widely used amperage ratings of common wire sizes kinda assume a set voltage.

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No, not at all.
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Lower the voltage and it should be able to carry more amps right?? Given the automotive 12v systems as an example.

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Absobloominglutely NOT RIGHT!!!
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And as far as having 2 hot wires on 220v to "share the load" not being an acceptabe argument puzzles me too.

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In a 220/240 VAC circuit all the current flows in both wires in series. The chief difference is that a 240 volt circuit with a given size wire will deliver twice the watts of the same wire running 120 VAC.

The two wires do NOT SHARE the load such that each handles 1/2 the current. They both carry all the current. In a 120VAC circuit all the current passes through the hot wire AND the neutral in series. IN a 240VAC circuit the same thing happens. The wires are in series NOT PARALLEL!!
+++++++++++++++++++++++++++++
Again, I'm not trying to be argumentative or unsafe, I just don't understand the logic of the code. If someone could shed a little light on it for me please am all ears.

BTW My powercord for the welder is not tucked behind any walls, and I don't feel the least bit unsafe running my welder to max with it's 12ga powercord plugged into a 40amp breaker. Call me crazy

I know a guy who walked across the street without looking either way. He did it several times and was not killed or injured. Does that constitute a safe practice? Because you haven't burned up the wire or your house yet doesn't make it a good idea to get others to try.

P.S. I'm not a degreed electrical engineer nor did I play one on TV and I didn't stay in a hotel or motel room, recently. My last job title was scientist but now I run a small cow calf operation on my 160 acres. (14 momma cows, a bull and 9 calves and counting) OK I confess I have in the past, (but only for a few years) made a living as an electronics design engineer.

Pat

 

[LD1]

If a 14ga wire is rated for 15amps at ANY voltage why is it rated for 40amps in a 12V system????

The more I research this the more i think I am starting to understand.


Transit: according to my calculations, 240v system with 12ga wire and 40 amps 30ft length = 4.6 volt drop. Which is only 1.9% and is well under the 3% and 5% standards that I have been reading about, so why would the insurance company have a problem with me being under the 2% that you mention????

Like I said, I don't completely understand it., but I have found two calculators online (just google wire size calculator) and entered 30ft @ 40amps and 220/240v and both have said 12ga minimum.

I know what the code says and I know what the standard is for given amperage. All I am saying is that there has got to be more to it than just amerage.

You guys are telling me that it is unsafe and my insurance company better not find out yet I have found two calculators that says it's fine, I am only at 1.9% voltage drop, and I know from experience that it works and the wire does not get hot. So why does the standard say for 40amp that I need at least 8ga wire. What am I missing? There has got to be more to it.

 

[neucam]

My little 230 amp welder ac/dc has a 50 amp plug on it and a 50 amp breaker and they recommend #6 gage wire. That is the right way to go. Don't skimp on wire size, you will lose power and overheat the wires.

 

[patrick_g]

The more I research this the more i think I am starting to understand.

Like I said, I don't completely understand it.

I know what the code says and I know what the standard is for given amperage. All I am saying is that there has got to be more to it than just amerage.

What am I missing? There has got to be more to it.

It is good that you are researching the issue. There are a number of peripheral issues such as type of conduit, if any, enclosing the wires, how many strands in the conduit, and on and on.

It is not surprising that you may have found conflicting information on the internet. It certainly would not be the first time. Context of each reference is important as well as the source of the information. Not every source is of equal stature.

Pat

 

[LD1]

Example: If you were to use 600 volts to power a circuit wired with a wire safely able to carry up to 40 amps you could deliver up to 24,000 watts.

Using the same wire with 12 volts you could safely deliver up to 480 watts.

Pat

How is this true when "according to code" it would require a 8ga wire for the 600v/40amp application, when an 8ga wire is rated for 150amp in an automotive application.

 

[jsborn]

If a 14ga wire is rated for 15amps at ANY voltage why is it rated for 40amps in a 12V system????

14 ga wire could be rated for many different amperages depending on type of use. example in conduit is less than in air which is less than in free air (outside like on a pole). It is based on a lot of factors none of which Can be omitted thus the need of charts and specs. Just to muddy the water more there are different ratings based on allowable temperature rise of the wire.

Just keep in mind if you use a breaker bigger in amperage than the wire can safely carry as per the NEC regardless of the voltage you will eventually have a fire and you will not be insured if the fire Marshall finds it.

 

[patrick_g]

LD1 I said nothing about code, automotive design standards, or anything resembling those two things.

What I said is a simple fact that is true. Neither of us may choose to use the same wire for both applications but so what? I was giving an example that was supposed to make something clearer for someone who wanted to understand, not quibble.

I could have chosen #2 welding lead as the wire in the example and the comparison would still be clear, concise, correct and communicative. This is true even though that neither of us might choose #2 welding cable for either application. It was an EXAMPLE not a how to for any specific wiring task.

Pat

 

[LD1]

LD1 I said nothing about code, automotive design standards, or anything resembling those two things.

What I said is a simple fact that is true. Neither of us may choose to use the same wire for both applications but so what? I was giving an example that was supposed to make something clearer for someone who wanted to understand, not quibble.

I could have chosen #2 welding lead as the wire in the example and the comparison would still be clear, concise, correct and communicative. This is true even though that neither of us might choose #2 welding cable for either application. It was an EXAMPLE not a how to for any specific wiring task.

Pat

I did not say you mentioned anything about code. But you said "safley handle the load" which is where I went to the code for my example.

I am not trying to quibble either, just understand.

But the part where you said that 14ga wire is rated for 15 amps at "any" voltage is what I was disagreeing with, because it simply isnt true. And that is where the 12v auto example came in at.

If there is a difference in allowable ampacities between 12v and 120v, why is their no difference between 120v and 600v?????

I am no electrical engineer, but I do understand the basics of electricity which everyone is quoting. I understand ohms law, watts law, voltage drop, # of wires in a raceway, open air, temp rise, and all that good stuff.

What I don't understand is how amperage is the only way wires are measured for capacity. If that were the case, a 1000amp auto battery would require a wire about the diameter of a golfball.

 

[aczlan]

Also, a 240v system has 2 power wires to share the load at 7.5 amps each

In the US a 40 amp 240v circuit has two 40 amp legs, not two 20 amp legs, if you look at 40 amp 240v breakers, they are (often) a pair of 40 amp 120v breakers permanently connected to each other.

Like I said, maybe watts isn't the best, but there has got to be more to it than just amps.
I just used watts because watts seem to always be a constant. The power supplied.
Think of it this way, you run juice through a transformer. The volts and amps change. If volts go up amps go down and vice versa. But the total wattage (or Power) is still the same.

True, but at higher voltages the required wiresize is smaller, that is why they run transmission lines at such high voltages (.5 megavolts IIRC)

Aaron Z

 

[LD1]

In the US a 40 amp 240v circuit has two 40 amp legs, not two 20 amp legs, if you look at 40 amp 240v breakers, they are (often) a pair of 40 amp 120v breakers permanently connected to each other.


True, but at higher voltages the required wiresize is smaller, that is why they run transmission lines at such high voltages (.5 megavolts IIRC)

Aaron Z

When they run the power through the transformer the voltage goes way up, but the amperage goes way down, the total wattage is still the same.

As far as the breakers go, I have not heard that, but I will look into it.

 

[aczlan]

When they run the power through the transformer the voltage goes way up, but the amperage goes way down, the total wattage is still the same.

True, but the point is that the higher the voltage is the smaller the wire needed to do the same work.
That is why a car starter needs a large cable to do what you could do with a 30 amp 120v circuit running over a 10ga wire.

As far as the breakers go, I have not heard that, but I will look into it.

When you have a 240 volt circuit (note I am speaking of the US system, it is different elsewhere) you have two 120v lines which, if compared to ground you would find that one is at +120v and one is at -120v, they switch which is which 60 times/second (which is why the US grid is known as a 60 hertz grid). The voltage between them measures 240 volts.

Aaron Z

 

[Transit]

If a 14 ga wire is good for 15 amps @ 120 volts it will only be good for 15 amps at any voltage. voltage rating on wire is a measure of the insulation not the wire. it is how much voltage the insulation will withstand before it breaks down and shorts out.

Current is the amount of electron flow a wire can stand before it breaks down due to heat.

You can do a lot of things with wire but to be safe you should always stay below the current rating of the wire no matter what the voltage is.

Your reasoning about 240 having 2 legs is flawed some what since you are not taking into account that for a fixed load the current will be somewhat divided between the two legs but not at a 50% rate. i can give you more information on how this works but I can say that if a wire is rated for 240 it will not carry twice as many amps as the same ga wire that is rated for 120volts.

I was with you jack and then you went into the ditch. The current in the two-pole circuit breaker leaves one pole of the breaker and enters the other pole to complete the circuit. There is no 50-50 split or any other such voodoo.

Example: 120 volt @ 15 amps, single phase, # 14-ga wire, one pole breaker.
120 x 15 = 1,800 watts. Maximum power attainable.

With a 4% voltage loss # 14-ga wire at 25-foot max length.
120 x .94 x 15 = 1,692 watts

# 10-ga wire will have the same loss at 50 feet.

Same problem; 240 volts @ 15 amps, single phase, two-pole breaker.
240 x 15 = 3,600 watts. Maximum power attainable.

With a 4% voltage loss # 14-ga wire at 50-foot max length.
240 x .94 x 15 = 3384 watts

# 10-ga wire will have the same loss at 75 feet.

You can see that doubling the voltage will double the power for the same wire gauge and increase the circuit distance.

There are other NEC tables taking other conditions into account such as insulation temperature range and operating temperatures.

 

[jsborn]

I was with you jack and then you went into the ditch. The current in the two-pole circuit breaker leaves one pole of the breaker and enters the other pole to complete the circuit. There is no 50-50 split or any other such voodoo.

Example: 120 volt @ 15 amps, single phase, # 14-ga wire, one pole breaker.
120 x 15 = 1,800 watts. Maximum power attainable.

With a 4% voltage loss # 14-ga wire at 25-foot max length.
120 x .94 x 15 = 1,692 watts

# 10-ga wire will have the same loss at 50 feet.

Same problem; 240 volts @ 15 amps, single phase, two-pole breaker.
240 x 15 = 3,600 watts. Maximum power attainable.

With a 4% voltage loss # 14-ga wire at 50-foot max length.
240 x .94 x 15 = 3384 watts

# 10-ga wire will have the same loss at 75 feet.

You can see that doubling the voltage will double the power for the same wire gauge and increase the circuit distance.

There are other NEC tables taking other conditions into account such as insulation temperature range and operating temperatures.

Its not Voodoo I will try to restate what i said ..IF you take a load of X and a Voltage of 120v then you have a current of Z. If you raise the voltage to 240v for the same load X the current will not be exactly Z/2.

if you really want to muddy the water you are correct that on a 240 system the current leaves one pole of the breaker and returns on the other one but not at the same time since one pole it one the neg side of 0 while the other is on the pos side 60 times a second the current is actually 0 on both poles.

I think the reason there is so much confusion about comparing automotive and household current is prob due to the duty cycle. Not to mention the fact that one is AC and the other is
dc. Household currents are given and designed for more of a 100% cycle and automotive loads are normally of a shorter duration. While a Car Battery is able to supply hundreds of amps under normal conditions it will be delivering that current for only seconds as opposed to all day or hours at a time therefore a smaller wire can be used. I will guarantee you if you short out your # 8 battery cable to ground and hold it there it will melt

One thing I am very sure of though is if you put 100 amps on a conductor that is rated at 50 amps it will melt no matter what the voltage is.

 

[LD1]

When you have a 240 volt circuit (note I am speaking of the US system, it is different elsewhere) you have two 120v lines which, if compared to ground you would find that one is at +120v and one is at -120v, they switch which is which 60 times/second (which is why the US grid is known as a 60 hertz grid). The voltage between them measures 240 volts.

Aaron Z

I understand the voltage of a 240v system but the amps and breaker is what I have a hard time understanding.

I have been told before that you could use 2 20amp breakers to make 40amp 220, as long as you connect the switches, so they trip together and you dont single-phase whatever your hooked to with 110v power.

 

[LD1]

One thing I am very sure of though is if you put 100 amps on a conductor that is rated at 50 amps it will melt no matter what the voltage is.

My truck has a 130amp alternator and is connected to the battery with a 6ga wire and I can drive all day long and the wire doesn't melt. Same 6ga wire is only rated for 50 of 60 amps @600v. This is why I am saying that there is more to it than amps.

I think we were onto it with the voltage drop. The NEC codes for MAX amperage and the standards that everbody referes to (12ga-20amp/10ga-30amp/8ga/40amp, and so on), what length of run are they figured at. Most auto wiring, like batter-alternator-starter wiring is 8-10ft max. Most 120v+ applications are 100+ft.

 

[jsborn]

I understand the voltage of a 240v system but the amps and breaker is what I have a hard time understanding.

I have been told before that you could use 2 20amp breakers to make 40amp 220, as long as you connect the switches, so they trip together and you don't single-phase whatever your hooked to with 110v power.

you can make a 20 amp 230 volt breaker with 2 20 amp 120 volt and a common trip bar. But if you need a 40 amp 230v breaker using 2 20's wont work it just don't add up that way no matter how much you want it to.

 

[aczlan]

My truck has a 130amp alternator and is connected to the battery with a 6ga wire and I can drive all day long and the wire doesn't melt. Same 6ga wire is only rated for 50 of 60 amps @600v. This is why I am saying that there is more to it than amps.

Amps, voltage and AC vs DC are all factors in wire sizing. According to the table here you can run 150 amps @ 12 volts for up to 10' through 8 gauge wire, so 130 amps through 6 gauge should be good.

Aaron Z

 

[Marada]

Wow, what a response. Sounds like a lot of ways that hooking up a welder have been tried. I talked to the electrician and work and here's what I plan. 8 guage wire to the recepticle. This will be dedicated to a 40 amp breaker. That should handle about all this welder can throw out. That leaves taking care of times that I have to work on equipment that I can't move close enough to the welder. If the welder works good then I'll just get extra long leads. I remember seeing a Lincoln 225 with 100 foot leads so I figure that'll work. Now if I can score a plasma cutter!!

 

[LD1]

Amps, voltage and AC vs DC are all factors in wire sizing. According to the table here you can run 150 amps @ 12 volts for up to 10' through 8 gauge wire, so 130 amps through 6 gauge should be good.

Aaron Z

Exactally my point. That there is more to it than just plain old amps.

So far I have come up with these factors that affect wire size
1.Amps
2.Volts
3.Length of run

The two wire size calculators that I found on google, one of which I posted earlier, these are the three main things they ask. As well as 1 or 3 phase and copper if aluminum wire.

So I think I have pretty much come to the conclusion that the most accurate way to size the wire is base off the voltage drop. As that is what the online calculators are doing.

I know there is a lot more to it, such as solid vs stranded, open air vs raceway, # of wires in raceway of conduit. All of these pertain to how hot the wire will get. And obviouslly the hotter, the less current it can carry.

As far as my 240v welder on a 40A breaker with 30 ft of 12ga soow, i have yet to find anything that says it is too small, except the people on here. So if anyone has any formulas or proof that it is dangerous, enlighten me. And I don't mean "code says 40A needs a min of 8ga" or whatever. Show me formulas. Voltage drop, temp of wire carrying said current, etc.

Again I am not being argumentative or hostile, i just want some real #'s and some real reasoning. And not just the same old standards that we are all used to. 14ga/15a 12ga20a 10ga30a yadayadayada. I already know that. I'm just trying to learn some reasoning behind it with some actual formulas or #'s