Is it OK for the side of the tip to touch earth?

[jweaver]

I just got my R-tech 30C and will hopefully be able to try it out this week.

One assumption i had was that the tip should not "short" to earth... But watching the official video, they run the tip along a length of metal which is clamped to the material being cut, which in turn is earthed, to get a straight line.

I guess this means that its OK to the touch the side of the tip to ground..

Jon

 

[Robotstar5]

You can get castle tips that are designed to run along (touch) the workpiece

 

[jweaver]

You can get castle tips that are designed to run along (touch) the workpiece

I assume thats what i have.. The tips have a "cross" in the end.

In the R-tech video, they clearly run the tip along a metal guide, so i assume its ok.

 

[gordon stephenson]

If your nozzles have a recessed cross as you say, then it is usual to drag it on the metal being cut.

 

[MattH]

It's a ceramic shroud that touches any guide you might be using. The metal tip would only be touching the material being cut.

 

[gordon stephenson]

With my Hypertherm the side of the copper nozzle also runs along the thin metal guide that i use for guiding straight cuts with no ill effects whatsoever.

 

[Wendelspanswick]

With my Hypertherm the side of the copper nozzle also runs along the thin metal guide that i use for guiding straight cuts with no ill effects whatsoever.

It's the same on my CUT50, I drag the cutting tip along a thin guide, if I dragged the ceramic shroud I would have to use a thick guide bar.

 

[jweaver]

It's a ceramic shroud that touches any guide you might be using. The metal tip would only be touching the material being cut.

Not according to the video (see 1:52 onwards):

I am sure its OK, but still trying to understand how, as the whole process is an electrical circuit and i assume that by touching the side of the tip to ground, it would cause a problem.. But perhaps i am over thinking this...

 

[Wendelspanswick]

Not according to the video (see 1:52 onwards):

I am sure its OK, but still trying to understand how, as the whole process is an electrical circuit and i assume that by touching the side of the tip to ground, it would cause a problem.. But perhaps i am over thinking this...

Where your going wrong in your thinking in having to have a gap between the electrode and the ground (earth) is that the arc is actually initiated in the gap between the inner and outer electrode (the 2 different consumables), compressed air then blows this arc out of the hole in the outer electrode.
On my CUT50, which has no pilot arc, the outer electrode has to be grounded to start the arc. I imagine that on plasma's with Pilot Arc the outer electrode has a temporary circuit used to ground the outer electrode until the arc is initiated whereupon the arc makes contact with the material being cut negating the need for the pilot circuit.

 

[jweaver]

Where your going wrong in your thinking in having to have a gap between the electrode and the ground (earth) is that the arc is actually initiated in the gap between the inner and outer electrode (the 2 different consumables), compressed air then blows this arc out of the hole in the outer electrode.
On my CUT50, which has no pilot arc, the outer electrode has to be grounded to start the arc. I imagine that on plasma's with Pilot Arc the outer electrode has a temporary circuit used to ground the outer electrode until the arc is initiated whereupon the arc makes contact with the material being cut negating the need for the pilot circuit.

Cheers.. I am indeed thinking about this wrong.. I am thinking of it as a MIG where touching the tip, and causing a short is bad.

But in the case of the Cutter, it looks like its OK..

Cheers

Jon

 

[chunkolini]

I have the 40amp Rtech plasma cutter and stoped using the ceramic tips a couple of years ago. I find they get i the way and make it hard to follow a line.
I have not noticed any problems with doing this.

 

[Wedg1e]

My Oerlikon seems to be quite happy to have its torch tip dragged along the surface being cut... it makes for fewer sparks off the topside for a start.
Pilot arc design, no castle tip.