Powermax cutting fine without ground lead

[chasxjs]

I recently up-graded to a Powermax 45. Everything is working great.
However, yesterday after cutting a design with over 100 pierces with various length cuts, I noticed that I had failed to connect the ground (return) lead to the material.
At first I thought I may have had the mode switch in the expanded metal position. However, it was set correctly to the plate position.
My previous cutter (pilot arc) would only stay on for about 3 seconds if the material ground was not connected and I don't understand why this one does not seem to make any difference if it's on or not.
Has anyone else experienced this? Perhaps the machine is somehow stuck in the expanded metal mode?

[WyoGreen]

I can say that my PM45 will not cut without the ground clamp (I have forgotten to put it on a couple of times). I don't think it will cut in any mode without a ground. Perhaps the torch is finding ground thru the table grounding system?

Steve

[CNCCAJUN]

When you say "not connected", do you mean laying on the floor & not touching the table at all?

The lead coming from a plasma cutter, the "WORK LEAD" is not a ground, it is on the positive side of the flow.

A lot of people run with the ground attached to the material support slats, but I can tell you first hand that a direct connection to the material being cut improves the quality of the cut.

I believe it also increases the life of your consumables.

Steve

[chasxjs]

Thanks for the replies.
Yes, I know it is actually not a ground. I was just referring to it both ways (ground and return)for clarification purposes.
The lead was not attached to the table or work piece. It was hanging on the wall and I could not detect any difference in the cut at all. It's just not making any sense to me.

[CNCCAJUN]

Not sure, but I think I read that you can cause damage to your plasma cutter doinging this . . .

Search Jim Colt's posts . ..

Steve

[chasxjs]

Sorry Cajun, Maybe I didn't explain myself correctly. I did not intend to leave the ground off. It was mistakenly left off and after I discovered it was left off, I realized that it did not seem to make any difference.
As I said I do not plan to leave it off. I am however now wondering if it indicates there is a problem with my new Hypertherm.

[CNCCAJUN]

I know chasxjs . . .

I assumed same . . . this keyboarding thing sometimes conveys just enough to confuse everyone.

I'm sure Monday Jim will see your post and comment.

Don't know for sure, but like I said earlier, it will cut, just not good for it from what I remember.

What I have done on my table is leave the big Hypertherm clamp on a piece of brass attached to my center slat support all the time. It never come off. From that same brass block I have another 15' cable with a 200 amp TWECO low profile clamp coming off of it. That gets attached to the material being cut. I just started doing the extra clamp and it definitely makes a difference.

I am guilty, I used to be a slat only guy . . . works great on a new table, new slats. . . but that ends soon . .

Steve

[chasxjs]

Tried it again today on a quick cut and same results. Curious to see what Jim Colt has to say.
I normally use a magnetic block for the work lead.
However, the second lead to the slats is a good idea for those times i do get in a hurry and forget.

[beefy]

When you say "not connected", do you mean laying on the floor & not touching the table at all?

The lead coming from a plasma cutter, the "WORK LEAD" is not a ground, it is on the positive side of the flow.

A lot of people run with the ground attached to the material support slats, but I can tell you first hand that a direct connection to the material being cut improves the quality of the cut.

I believe it also increases the life of your consumables.

Steve

Steve,

I believe "ground" can be positive OR negative. The word "ground" does not refer to a polarity. It just so happens that most grounds with DC current are negative. However, as an example of the other way around, you may often see references to positive "earth" vehicles for example. One dictionary example of the word ground in the electrical sense is "a large conducting body, connected to earth". However "ground" normally gets applied to the "bulk" of something, in our case the table, slats, etc. It can be either polarity.

One thing is certain, electricity must complete it's path from one polarity to the other and that path is being completed somewhere

[CNCCAJUN]

I agree . . . Although I have been corrected about calling the WORK LEAD a "GROUND" several times.

The ironic part is if you look at the recommended setup for some of the high end machines they take the WORK LEAD to the EARTH GROUND FIRST & then to the table.

The whole grounding & how to ground seems to vary from installation to installation in order for that system to work.

What I do know is the WORK LEAD / GROUND needs to be in contact with the material through some path.

In the original posters case I am mystified. This may turn out to be a learning experience for us all.

Steve

[jimcolt]

You don't mention if you are cutting by hand....or with torch mounted on a machine. Using shielded or non-shielded consumables?

If cutting on a cnc machine (what brand/model) you could be getting a "work" connection back through the interface wiring......which is not good...and ultimately will cause damage to wiring or internal components. The arc should extinguish in a couple of seconds if you do not have a work cable connection....unless you are in expanded metal mode.

Jim Colt Hypertherm

I recently up-graded to a Powermax 45. Everything is working great.
However, yesterday after cutting a design with over 100 pierces with various length cuts, I noticed that I had failed to connect the ground (return) lead to the material.
At first I thought I may have had the mode switch in the expanded metal position. However, it was set correctly to the plate position.
My previous cutter (pilot arc) would only stay on for about 3 seconds if the material ground was not connected and I don't understand why this one does not seem to make any difference if it's on or not.
Has anyone else experienced this? Perhaps the machine is somehow stuck in the expanded metal mode?

[_Ogre]

we rarely connect the ground to the metal sheet on our table, unless cutting stainless
but the slats, table, earth ground rod and plasma cutter ground are all connected together
you maybe grounding thru wet concrete and your house wiring
but eventually something will give and you will let the smoke out of your house wiring
electricity will choose the path of least resistance