Welding Tips and Tricks

The welder transformers use thin wires compared to jumper cable used for electrode holder and ground. Why thick jumper cable is used for arc welding? I also found some difference while using thin 12 gauge wire for ground and holder and jumper cable . But how can only thick output cables for short distance do so much?

The thickness of the cable drives the machine's ability to deliver amperage. Machines that offer a lot of power will have thicker cables, and vice versa. Sometimes the thickness of the cable is driven by the manufacturer trying to achieve a particular price point, so a cheap 110v arc welder will have the thinnest wire that could feasibly do the job.

All conductors offer resistance to the flow of electricity. Imagine each strand of copper in the cable. If one strand carried the whole 300 amps, (not so unusual a welding current), the resistance to the flow of electricity causes heat, large current in a small conductor would instantly melt it. With hundreds of these strands sharing three hundred amps, no problem.

Lets compare TIG leads; air cooled torches carrying 200 amps must be big and heavy. Large cable is needed. A water cooled torch might have a conductor 1/4 the size, carry 200 amps, and stay cool because of the flow of return water through the cable.
I will point out that we pay a big price for the light weight of this cable. Electricity is still being wasted in the conversion to heat. Our electric meter measures more usage, we need bigger power cable to the welder. We may need a bigger welder, we are unable to weld as thick aluminum. Compare the ground lead to the torch lead in a water cooled torch. They carry the same amperage.

Bill Beauregard wrote:All conductors offer resistance to the flow of electricity. Imagine each strand of copper in the cable. If one strand carried the whole 300 amps, (not so unusual a welding current), the resistance to the flow of electricity causes heat, large current in a small conductor would instantly melt it. With hundreds of these strands sharing three hundred amps, no problem.

Lets compare TIG leads; air cooled torches carrying 200 amps must be big and heavy. Large cable is needed. A water cooled torch might have a conductor 1/4 the size, carry 200 amps, and stay cool because of the flow of return water through the cable.
I will point out that we pay a big price for the light weight of this cable. Electricity is still being wasted in the conversion to heat. Our electric meter measures more usage, we need bigger power cable to the welder. We may need a bigger welder, we are unable to weld as thick aluminum. Compare the ground lead to the torch lead in a water cooled torch. They carry the same amperage.

Thanks for so much info, But you know why do the arc welders use thick cables only for rod holder and and ground even though they have thin wire wound on transformers. I have seen that people use thick jumper cables only for holder and ground even though the welder transformer has thin secondary. Why thick jumper cables output? Do using thick cables just for holder and clamp reduce load on secondary or anything like that?

That thin wire you see is probably just the primary (mains side). It is carrying voltage, not amperage. The cable side is doing the exact opposite so it must be thicker.

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AdVirMachina wrote:That thin wire you see is probably just the primary (mains side). It is carrying voltage, not amperage. The cable side is doing the exact opposite so it must be thicker.

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Come on, I am not that naive. Okay so you think the welding transformers actually have thick jumper cables wrapped around their secondary. Obviously NO, so but why do everyone use thick jumper cables just to feed the holder and ground? even if the secondary is thinner.
In many cases I found thickness of wires as:
Jumper Cables(Holder & Clamp)>Secondary Wire>Primary Wire

I believe this article will be most helpful to you.
http://www.lincolnelectric.com/en-us/su ... ables.aspx
-Jonathan

The leads are actually taking the brunt of the work.
If your ground and rod lead are getting hot, it's a good sign that you need bigger cables.

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Deltawelder@101 wrote:

AdVirMachina wrote:That thin wire you see is probably just the primary (mains side). It is carrying voltage, not amperage. The cable side is doing the exact opposite so it must be thicker.

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Come on, I am not that naive. Okay so you think the welding transformers actually have thick jumper cables wrapped around their secondary. Obviously NO, so but why do everyone use thick jumper cables just to feed the holder and ground? even if the secondary is thinner.
In many cases I found thickness of wires as:
Jumper Cables(Holder & Clamp)>Secondary Wire>Primary Wire

I scrapped a Hobart AC heavy duty welder last spring. Its secondary was copper strip over an inch wide, (30 MM) thin maybe a MM. It'll take someone smarter than I to explain the smaller cross section of winding than welder cable. The fan blowing across it might explain the ability to cool.

Are you referring to an inverter welder? Those have much smaller transformers compared to a traditional transformer welder.
The 50-60 Hz input is modulated into high frequency before going into the transformer. Hi freq can be put thru a smaller transformer hence the thinner wire (secondary is always thicker than primary in a welder). After the current is rectified (or modulated to a lower freq if AC welding) heavier wire is then required to carry the higher amps.

Okay so you think the welding transformers actually have thick jumper cables wrapped around their secondary

Take a look at the secondary of a spot welder, just a few coils of very heavy gage

Deltawelder@101 wrote:The welder transformers use thin wires compared to jumper cable used for electrode holder and ground. Why thick jumper cable is used for arc welding? I also found some difference while using thin 12 gauge wire for ground and holder and jumper cable . But how can only thick output cables for short distance do so much?

Because it's not always a short distance. I've welded with 800 Meters combined power and ground between my power source and the arc. Heavier conductors have less voltage drop. Voltage drop is the enemy of a constant-current source, because the power requirement goes up to deliver the same current, in the formula P=IE (Power equals current times voltage). The welder must up the voltage to maintain a constant current against the resistance of the leads.

The relatively thin windings of the transformer can handle a certain amount of power, and the heavier the conductors between the transformer and the arc, the less "additional" power load the transformer sees.

I hope this helps explain it.

Steve S

Otto Nobedder wrote:

Deltawelder@101 wrote:The welder transformers use thin wires compared to jumper cable used for electrode holder and ground. Why thick jumper cable is used for arc welding? I also found some difference while using thin 12 gauge wire for ground and holder and jumper cable . But how can only thick output cables for short distance do so much?

Because it's not always a short distance. I've welded with 800 Meters combined power and ground between my power source and the arc. Heavier conductors have less voltage drop. Voltage drop is the enemy of a constant-current source, because the power requirement goes up to deliver the same current, in the formula P=IE (Power equals current times voltage). The welder must up the voltage to maintain a constant current against the resistance of the leads.

The relatively thin windings of the transformer can handle a certain amount of power, and the heavier the conductors between the transformer and the arc, the less "additional" power load the transformer sees.

I hope this helps explain it.

Steve S

Thanks this explains a lot.

Thanks to everyone for their valuable reply.

Current actually flows as slow as peanut butter. http://www.physlink.com/Education/AskExperts/ae69.cfm
If your AC welding, it isn't flowing at all. It vibrates and the vibrations move thru the wire.

Electrons are perceived as moving as fast as the speed of light, because as one electron goes into the wire, another one gets bounced out the other side at roughly the speed of light. The actual electron going into the wire, won't be coming out the other end for quite a while.

If you want to disable a transformer, stick a strong permanent magnet on it. This will effectively saturate the magnetic field in the transformer and thus stop it from functioning. Magnetic amplifiers use this principle. The German V2 rocket used this technology.

WerkSpace wrote:Current actually flows as slow as peanut butter. http://www.physlink.com/Education/AskExperts/ae69.cfm
If your AC welding, it isn't flowing at all. It vibrates and the vibrations move thru the wire.

Electrons are perceived as moving as fast as the speed of light, because as one electron goes into the wire, another one gets bounced out the other side at roughly the speed of light. The actual electron going into the wire, won't be coming out the other end for quite a while.

If you want to disable a transformer, stick a strong permanent magnet on it. This will effectively saturate the magnetic field in the transformer and thus stop it from functioning. Magnetic amplifiers use this principle. The German V2 rocket used this technology.

But peanut butter doesn't flow at all!

You need to have a basic understanding of electricity and electrical circuits. As well ad some laws of physics... Then you will answer your own questions. .

https://learn.sparkfun.com/tutorials/vo ... d-ohms-law

soutthpaw wrote:You need to have a basic understanding of electricity and electrical circuits. As well ad some laws of physics... Then you will answer your own questions. .

WerkSpace, you are full of some of the oddest factoids my friend. Thanks for keeping it refreshing.

As he says in disbelief, I've never seen or heard that before.

GreinTime wrote:WerkSpace, you are full of some of the oddest factoids my friend. Thanks for keeping it refreshing.