>As a basic know-nothing on this topic, I'm confused.
>
>I can understand how one type wire may have more resistance and require a
>higher voltage to get the right temp, but power? Power relates to heat
>output and should be sensitive to factors like cutting speed, wire length,
>material being cut, even wire diameter. If these factors are all constant,
>I fail to see how the type of wire can have any effect on power requirement.
>Can anyone explain this?
>
>Rick,
>
>>You need less power if you use piano wire. I've been using this for a while
>>now and it works well.
>
Most wire has a positive temperature coefficient of resistance which means
the resistance increases with temperature. As an example, the tungsten
filament in an incandescent lamp has a hot working resistance about 20 times
greater than its room temperature resistance. The transformer ratings may be
constant but that just refers to the upper safe limit. Most foam cutting
power supplies have some form of voltage adjustment which, with the heated
wire resistance, produces a current. If properly designed and used, the
actual voltage, current and power at any particular adjustment are at or
under the rated values for the components.
Regards, Ollie
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