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Posted by Andrew Mawson on July 30, 2007, 12:05 pm
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> Hello to the welders:
>
> I have recently acquired a small stick welder that operates on 110
> volt supply. The existing amperage control is a two way switch that
> selects either 50 amps, or 90 amps. I do not wish to use this
welder
> in 90 amp mode as the duty cycle is ridiculous at this setting. I
> also want to be able to control the current in smaller steps and be
> able to run the welder as low as 30 amps for some sheet metal
> purposes.
>
> Is it reasonable to swap out the coarse, two position output
amperage
> switch with a type of rheostat or potentiometer that could deliver
> lower amperage and smaller increments of adjustment?
>
> I am not a complete knucklehead with electricity, basic circuitry,
and
> wiring in general. I have not however worked with a welder
assembly.
> What would the preconditions and precautions that should be observed
> when planning such a modification? Has anyone been involved in such
a
> modification to a welder's circuitry?
>
> Thanks,
> Skeeter.
>
VERY much depends on what sort of welder. If it is a simple
transformer buzz box, the amperage control could either switch between
tappings on the transformer (which actually changes the voltage, and
the current follows) or it could switch in varying amounts of
inductance from a choke. For this type of welder forget rheostats or
potentiometers - the power you are handling is far too much. (Pure
inductors are effectively a wattless resistance in an ac circuit)
If it is an inverter type then it very much depends on what the two
stage control actually does in the circuit.
AWEM
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>
>I have recently acquired a small stick welder that operates on 110
>volt supply. The existing amperage control is a two way switch that
>selects either 50 amps, or 90 amps. I do not wish to use this welder
>in 90 amp mode as the duty cycle is ridiculous at this setting. I
>also want to be able to control the current in smaller steps and be
>able to run the welder as low as 30 amps for some sheet metal
>purposes.
>
>Is it reasonable to swap out the coarse, two position output amperage
>switch with a type of rheostat or potentiometer that could deliver
>lower amperage and smaller increments of adjustment?
>
>I am not a complete knucklehead with electricity, basic circuitry, and
>wiring in general. I have not however worked with a welder assembly.
>What would the preconditions and precautions that should be observed
>when planning such a modification? Has anyone been involved in such a
>modification to a welder's circuitry?
>
>Thanks,
>Skeeter.