Welder Voltage help

Ahhh problem solved. For those with the same question, I was doing something totally unrelated and came across this formula for Work -

W=VIT Work=Voltage Times Impedance Times amount of time

So, whilst 100 Amps is 100 Amps at 45 or 70 Volts, at 70 it is just travelling a whole lot faster (so you have the same car, it is just going almost twice as fast.....) - so good for faster welding or thicker peices - but I can get a higher amperage at the lower voltage because they both have to convert from my house suppply of 240V 15A

Drewe

Well, sort of but your interpretation of the forumula is wrong. The I stands for current, not impedance. The VI is power and T is the time that amount of power is applied. I think the main reason of the lower voltage is to reduce the amount of resistance and thus heating of the transformer at higher currents. Having a higher voltage at lower currents makes striking the arc a lot easier. Striking the arc at high currents isn't usually much of a problem. The voltages you specified are the Open Circuit Voltages of the machine often abbreviated OCV. These voltages are not the arc voltages but what you would measure with your voltmeter with no load on the welder. The arc voltage is defined by the current, electrode distance from the workpiece and internal impedance of the welder and are always lower than the OCV.

Billh

The higher voltage is easier to use when you are striking the arc. After the arc is started, the voltage is the same regardless of which voltage you started on. In an arc welder the coupling between the primary and secondary of the transformer is not real high.

Dan

Arc (stick) welders, along with TIG welders, are

on striking the arc the voltage does whatever is necesssary to hold the arc to the current you set, be it 50A, 70A 130A or whatever.

(MIG is the different one - it's constant voltage)

Richard Smith

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