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UA440Fitter
11-16-2008, 09:17 PM
I posted this in the General Welding Questions Forum.... http://weldingweb.com/showthread.php?t=25405

Maybe someone that reads this forum can answer it:

When researching how plasma cutters initiate their start, you always get these two answers:

There are two methods used to create the plasma for plasma cutting.

1. HF (High Frequency) Contact. This method is generally used in low budget equipment since it cannot be used for CNC (Computer Numeric Control) Plasma Cutting operations. To generate plasma, this method uses a high frequency, high voltage spark. When the plasma torch touches the material to be cut, thereby closing the circuit, the spark fires into the torch head and plasma is created.
2. Pilot Arc. This method is a little more involved since it produces plasma in two cycles. Cycle one: inside the body of the torch a low current, high voltage circuit creates a high intensity spark. This spark creates a small volume of plasma (the pilot arc). Cycle two: the pilot arc remains static until the torch head is touched to the metal at which point a trigger allows the pilot arc to light the main flow of gas and plasma cutting begins.

Now.... My Lincoln uses the second method. Squeeze the trigger, little blue flame appears, get close to metal and plasma stream starts.

Chinese Plasma Cutters..... I have one. It does not have a pilot arc. BUT..... I do not have to make any contact with the grounded material to start the plasma. If I get within 1/4", it immediately starts to cut. Wadda-ya call that? (Be nice)

For the very same Chinese Plasma Cutter, you can purchase a "Pilot Arc" torch. Now comes massive confusion! :confused::confused:

Life was so simple with oxy-acet!

Bret

Oldiron2
11-16-2008, 09:41 PM
If the HF output is also high voltage, the current can jump the gap just the same as with a TIG torch.

EVERLAST_SUPPORT
11-16-2008, 10:39 PM
Alex gave me a couple days off. Just popping in.

I never have a problem with HF, I do it through painted metal all the time as long as I have a good ground. The power will jump through the paint and start the arc (as Oldiron2 said). If you have a CNC, you will find a bump of the torch to the material will start the arc. Run the CNC program/script from there.

I have two O/A sets. I keep them around for old time sake. If I need to bend something.

UA440Fitter
11-17-2008, 01:32 AM
If the HF output is also high voltage, the current can jump the gap just the same as with a TIG torch.

Yep.... I agree with that completely. What was confusing me was how you could place a different torch on the unit and all of a sudden have a Pilot Arc system. After doing more investigation, I figured that out. See my second post in this thread: http://weldingweb.com/showthread.php?t=25405


Now I will be able to sleep tonight! :D:D

Bret