MIG amperage

[jake98]

Do wire feed MIG welders increase amperage by having more 'connection' as the wire speed increases? I just ordered one, and I'm trying to get the picture of how they 'know' to increase the amperage..:confused2:

 

[deereman75]

They ''know''*to increase the amperage when you turn up the amperage with the knob.

 

[jake98]

They have a voltage knob, and a wire feed speed knob. Voltage only varies by about 15v., or something.. thus my question..

 

[FredH]

What welder are you purchasing ? Not sure about " Voltage " but my Lincoln SP135 goes from "A" to like "J" on amperage which is like 20 amps up to some were around 130 amps . Wire feed is the same and unless it is really thin gauge metal , I am always around 3 to 4 on the wire speed .

Fred H.

 

[jake98]

What welder are you purchasing ? Not sure about " Voltage " but my Lincoln SP135 goes from "A" to like "J" on amperage which is like 20 amps up to some were around 130 amps . Wire feed is the same and unless it is really thin gauge metal , I am always around 3 to 4 on the wire speed .

Fred H.

Are you sure you have an 'amps' control? All I've been looking at (which aren't that many) have voltage control and wire speed. What it's got me wondering is if the amps gets controlled by the wire burning off and then re connecting at different rates.. like the full amps potential is always there, it just keeps getting interrupted, the less interruptions, the more amps?
Come to think of it, how can they put 200 amps thru a .035 wire without it melting right in the hose?
I ordered the Hobart Ironman 230.

Edit: I googled and found this http://www.millerwelds.com/resources/basicMIG/wire_feed_speed.htm

 

[Shield Arc]

OK, now that you have a handle on wire speed / amps, and volts, next you'll want to learn how to set a wire feeder up on an old school engine drive like in my avatar.

 

[J_J]

You are not just feeding voltage/amps through the wire, but you must consider the metal spiral cable that the wire runs through. If you look inside the welder, you will see that the wire housing is one leg of the current flow, and the very end of the wire is the short circuit, and melts the wire.

 

[deereman75]

They have a voltage knob, and a wire feed speed knob. Voltage only varies by about 15v., or something.. thus my question..

When you change the voltage, the amperage changes as well. The amps is what does the work. On a stick welder for example, the amps is constant, no matter what you do with the stinger. On a mig welder, the voltage is constant, no matter what you do with the mig gun. On a stick welder when you increase the amperage, it decreases the voltage. And why the wire doesnt melt in the hose, is because it doesnt carry any current in the hose, the current is carried in a differnt wire, and the contact tip is what energises the wire,right before it goes to the puddle. The reason the amperage changes is the way the transformer works, it has nothing to do with anything else.

 

[jake98]

OK, now that you have a handle on wire speed / amps, and volts, next you'll want to learn how to set a wire feeder up on an old school engine drive like in my avatar.

Yeah, right now I'm thinking I should have just bought a wire feeder and hooked it up to my tombstone.. Oh well, I love new toys anyway..

 

[Shield Arc]

I don't know anything about tombstones, but you have to be real careful with a lot of CC power sources, sometimes they put out too many OCV for some wire feeds to operate properly. Some of Lincoln's old wire feeds would only accept 49-OCV, the minimum result would be no wire feed until you struck and arc.