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View Full Version : Can I add a power adjustment to my cheap welder?



Larry R.
11-29-2009, 10:25 PM
Last fall my son gave me a cheap welder. It is 110 volt, constant 100 amps, I think. It worked pretty well for my StreetFox build since I was using 14 guage tubing. On thin bicycle tubing, however, it burns through. I read somewhere a rotary style light dimmer works for a power control on homemade welders. Does anyone know anything about this? Could I put a dimmer on this welder? Would it go somewhere along the power cord?

PeterT
11-29-2009, 10:45 PM
You would need to install it after the power switch, possibly replacing high/low switch with suitable rated trim pot. And then practise with various thicknesses of material, so you know where you various settings on the trim pot are.

PeterT

Radical Brad
11-30-2009, 02:24 PM
A light dimmer will not work because of two reasons; 1) the current needed by your welder will be well beyond the capacity of the dimmer and 2) a dimmer cannot deal with an inductive load such as a transformer or motor.

if you just want to have a little more control, figure out the wattage of your unit by multiplying the output voltage by the output amperage and then drop a load with a similar rating in series with the AC supply.

If your welder requires 2500 watts, then a stove coil in series at the AC line will certainly drop the output power due to its internal resistance. I do this a lot in my high voltage experiments when I have to plug a pole transformer into mains! By using several coils in a series/parallel combination, a lot of control can be had...

http://www.lucidscience.com/research/gator/004.jpg

Although this transformer had an output of 50Kilovolts, it is not much different than a huge welder transformer, just working in reverse.

of course, for the price of all that messing around, you could probably find a nice used welder someplace!

Brad

zobman
12-19-2009, 11:33 AM
And you can keep your coffee pot warm at the same time!!!!!!!


A light dimmer will not work because of two reasons; 1) the current needed by your welder will be well beyond the capacity of the dimmer and 2) a dimmer cannot deal with an inductive load such as a transformer or motor.

if you just want to have a little more control, figure out the wattage of your unit by multiplying the output voltage by the output amperage and then drop a load with a similar rating in series with the AC supply.

If your welder requires 2500 watts, then a stove coil in series at the AC line will certainly drop the output power due to its internal resistance. I do this a lot in my high voltage experiments when I have to plug a pole transformer into mains! By using several coils in a series/parallel combination, a lot of control can be had...

http://www.lucidscience.com/research/gator/004.jpg

Although this transformer had an output of 50Kilovolts, it is not much different than a huge welder transformer, just working in reverse.

of course, for the price of all that messing around, you could probably find a nice used welder someplace!

Brad

Radical Brad
12-19-2009, 12:52 PM
Indeed! As long as you don't mind a 3 foot high voltage arc jumping out of your java!

Brad