stupid question

[dulknife]

this is as close to a stupid question as i can get. how does the wire speed affect the amperage. when i taught a&p mechanics we said ask the question someone else wants to know also

[Guest]

Re: stupid question

Originally posted by dulknife
this is as close to a stupid question as i can get. how does the wire speed affect the amperage. when i taught a&p mechanics we said ask the question someone else wants to know also

Very true...but you are wrong about the "stupid question"...there are no stupid questions, here. You are right about wire & amps having a correlation. I want to hear the answer, too.

[Planet X]

OK, I will play. Let us liken a welder to a Dam. Now each Dam is sized according to how much water it can hold. So lets take the Powermig 255 this welder is basically the Hoover Dam in its 300 amp class. Now from time to time water is allowed to flow (current) by opening gates and the more gates you open the more current you will flow down river.
So if we think of the lake behind the dam as the voltage or 'pressure' the bigger the lake the more pressure potential we have. But the lake is only potential current until we open a gate.
The faster we open a gate the more current we flow down stream. And if we collected this water down stream we would get a gallons per minute measurement which can be called Amps.


A mig machine has two main controls, Voltage & Wire speed.
Voltage is the lake size and Wire speed is the rate of gate opening.
Both of these combined will give you the gallons per minute which is the weld energy or 'amps' you put into your weldement.

Also gallons per minute or Amps is also affected by Gate size or in this case electrode size-the bigger the wire the bigger the gate opening, potentially more flow.

[Hobart Expert Rock]

DULKNIFE...........LIKE ROCKY D STATED.......... NO STUPID QUESTIONS HERE........MY OLD ELECTRONICS TEACHER ALWAYS COMPARED ELECTRICITY TO WATER.............. OPENING AND CLOSEING GATES.....................HMMMMM I THINK I'M TELLING MY AGE HERE NOW AREN'T I................ IF YOU WANT I CAN EXPLAIN IT ANOTHER WAY....................................HAVE SOME FUN WITH IT..................ROCK.......................... .
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[Sberry]

I like a hose and valve analagy somewhat better as you can factor in the hose size, the resistance and how load affects it and pressure drop as load or flow increases.

[Bob]

Planet X,

Very nice visual picture. Higher wire speed gives more times the arc is flowing (more gate openings). More energy, more heat. But also more wire to be melted and to go somewhere I think?

Thanks,
Bob

[Thomas Harris]

Does the encrease in wire speed cause the short circut cycle to occurr more in a given time frame. I was under the impression that the wire , in short circut, burns off completely, then "re-short circuts" starting the current and heat again. faster wire speeds cause this to happen more frequently causing more heat? Maybe this is wrong. Somebody give a holler.

[Planet X]

Originally posted by Thomas Harris
Does the encrease in wire speed cause the short circut cycle to occurr more in a given time frame. I was under the impression that the wire , in short circut, burns off completely, then "re-short circuts" starting the current and heat again. faster wire speeds cause this to happen more frequently causing more heat? Maybe this is wrong. Somebody give a holler.

There is an OPTIMUM WIRE SPEED/VOLTAGE setting for short circuit, which you mostly listen for-frying bacon sound. That 'crispiness' is the arc on/ arc off cycle.


But remember your power source may be capable of other modes of transfer, globular, spray, pulsed. Each distinct,but same(mig welding).
Kindve like strata layers in the dirt. Short circuiting is the top layer digging a little deeper you run into the Globular layer, deeper still the Spray layer, then finally the Pulsed layer.

The above 'layer' depend on what you set your welding controls at and what process capabilities your machine has.
Other considerations can be; gas mix, electrode size, electrode stickout ....
Personally I use Short circuit & Spray I do my best to avoid Globular and I don't have a Pulse capable machine

[Planet X]

Originally posted by Bob
Planet X,

Very nice visual picture. Higher wire speed gives more times the arc is flowing (more gate openings). More energy, more heat. But also more wire to be melted and to go somewhere I think?

Thanks,
Bob

Thanks but I was just trying to wax poetic Here is a thought what if your dam does not have much water in it and you try to open all the gates? I used a Miller 185 at work and that rigs Dam must of been experiencing a drought when I was used .035 wire

[Sberry]

I agree with the 185. You will need to slow the wire up in it and it would run Soooo much better with .030 Because the wire feeder is a constant voltage machine when you speed up the wire and to keep the same output voltage the current needs to go up so the pump works harder.

[Hobart Expert Kevin]

Dulknife,
Some good replies on this already out here but I figured I would throw this chart info out too.

SHORT ARC CARBON STEEL, SOLID WIRE
wire size inches per amp
.023 4.2
.030 2.2
.035 1.9
.045 .93

FLUX CORED STEEL
.035 2.8
.045 2.1

By using these figures you can get a rough idea of where you are running as far as amperage. (example .035 solid wire @400 IPM 400ipm divided by 1.9 = 210 amps) This is not an exact science but it will get you in the ballpark. Hope this helps you out... and by the way this is not a stupid question!

Kevin


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