|01-09-2006, 11:52 AM||#21|
Join Date: Jun 2003
Location: Stratford, Ontario
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You are right, you don't need DC for cutting foam. In fact, you will lose a bit of voltage through the diodes (about 2 volts total for a loaded, full-bridge rectifier of 4 diodes).
You CAN get more voltage if you use a rectifier, and add a capacitor to the output - but it will have to be quite a big one. The capacitor will charge up to the peak AC voltage, so your new DC output will be about 1.4 times the AC voltage - at a cost of higher stress on the diodes and transformer. But your diodes and transformer are hugely overrated for wire cutting anyways. You have enough amps there to cut with 14-gauge steel fence wire!
I don't recommend taking turns off the primary - it will increase the magnetic flux in the core, causing increased losses in the transformer. If you take too many turns off, you will get magnetic saturation of the core, then the unloaded primary amps goes way up, and the smoke comes out.
The welder is rated 25 arc volts, this is at 50 amps load on the transformer. But notice the duty cycle is probably only 10% (or maybe 20%). The transformer is way overloaded at 50 amps, so the output volts gets dragged way down. Add the voltage drop from the too-thin welding cables, and you end up with only 25 volts at the arc. The transformer is probably good for only 10-20 amps continuous, without overheating.
|01-09-2006, 06:04 PM||#24|
I am: Ken Currell
Join Date: Jun 2004
Location: Whitby, Ontario
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Hi tech 1
How would I do that without a lot of cost?
Couldn't I limit the output by fusing the input lower?
I should never even get to 120 volts on the input side.
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