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Old 03-05-2007, 08:26 PM   #7
KTM640Dakar OP
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Joined: Nov 2004
Location: Oxbow Lake
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Originally Posted by Poolside
Say a drag tipped torch cutting .250 carbon steel sheet, with compressed air. The arc is running and the tip is dragging.

What is the approximate power supply output voltage measured across the leads at the supply side? Or, the arc voltage measured between the electrode and the workpiece.

Either one.

- Jim
To cut 1/4 inch plate you will need about 30 Amps. With plasma cutting the voltage is determined by the distance of the tip to the plate you are cutting. You don't really set the machine voltage on a hand held plasma cutter, you set amperage. The key to getting a good plasma cut is setting the right amperage to thickness and keeping the torch slightly above the surface you are cutting without touching the plate. You also need a steady hand, and don't move too fast. If you go too fast the spatter will shoot back at you. You also need clean dry compressed air with the right pressure setting. Most plasma cutters have recommended flow rates for their machine. Usually 65 psi. for a 50 Amp machine as an example. Also make very sure you have a new electrode and nozzle since these parts wear out and will effect cut quality.

Are you using an automated table plasma cutter or hand held plasma cutter? If you are using an automated plasma cutter then you would set voltage to control torch stickout.
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