THC issues

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dtdetail
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THC issues

Post by dtdetail »

Lately I've been struggling with my torch either slowly raising up throughout cuts, or slowly working its way down onto the workpiece.
this only happens when I'm cutting a large file, or long continues lines.

What's also odd is if I play with the "on the fly" THC (voltage adjustment) knob on my controller during cuts, it seems to not have an effect on torch height. The torch will also either raise or lower in the SAME spot. If I just let the system finish its program, return home, then start it all over again it will raise/lower in the same spot it did the last time around.

I do not have a grounding rod. Is this the cause?

Thanks
weldguy
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Re: THC issues

Post by weldguy »

Not sure what plasma table and thc system you are using but your issue is not a ground rod so waste your time with that. It is likely doing this all the time and you are just seeing it because it will be more obvious on long cuts. Let us know what table and thc your using.
dtdetail
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Re: THC issues

Post by dtdetail »

Table is a Tracker Protable, 4x8. Power source is a powermax65. THC is just based off voltage feedback from the power source to the table I believe.
adbuch
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Re: THC issues

Post by adbuch »

I agree with weldguy. Although it is a good thing to have a dedicated grounding rod, the lack of one should not be causing your thc problem.
David
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Re: THC issues

Post by acourtjester »

Troubleshooting can be hard, have you turned off the THC. Your problem seems to be errors with the THC, does it have a voltage display. Have you watched it while cutting. It will fluctuate but will not rise or drop unless following warps in the metal but not continue in one direction only.
Has the table work for some time or just started doing this problem. If just started what has changed??
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Re: THC issues

Post by weldguy »

dtdetail wrote: Thu Mar 02, 2023 6:03 am Table is a Tracker Protable, 4x8. Power source is a powermax65. THC is just based off voltage feedback from the power source to the table I believe.
OK and was the THC working properly previously and this problem came out of the blue with no changes to the hardware or software?
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Re: THC issues

Post by adbuch »

Great questions from both Tom and weldguy. It would be nice to know if this is a new install and you are just sorting out the bugs, or did you previously have it "dialed in" and this is something new.

David
dtdetail
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Re: THC issues

Post by dtdetail »

Thanks guys,

I have turned off the THC to test it and it seems to run okay.
I do not have a voltage display.
I have watched the arc, and it seems to stay exactly the same.
As far as I know the table ran fine up until a few months ago, I purchased it close to 2 years ago now, however a good 75% of my use on it has been in the last few months (day job slowed down a bit so I've got more time now). I have noticed the problem happens MUCH MUCH more often when running finecut consumables.

I should also mention that one time I forgot to remove a small piece of material from the tabletop and proceeded to lay a full 4x8 3/8" plate on top.
This of course caused the plate to have a nice big bend in it from the get go. When cutting over the section where the scrap piece was underneath, the torch did not detect the change in height, and rammed right into the workpiece. As if it didn't have THC at all.
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acourtjester
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Re: THC issues

Post by acourtjester »

It sounds like the THC has failed or maybe a wire broken. It is had to tell what is going on with no indicator of the arc voltage.
The THC should have reacted to the surface change going over the big bend, that is its job. Not sure if you understand how a THC works, it comes into play after the pierce (slight delay). And monitors the arc voltage and makes adjustments to the cut height for any changes in the arc voltage. The arc voltage will change if the cut height changes due to warps in the surface of the metal. The THC will compensate for the arc voltage changes moving the torch up or down to maintain the arc voltage at the set value.
Do you connect the Plasma work lead directly to the metal you are cutting, this is the best practice to insure a good circuit for the arc voltage.
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Re: THC issues

Post by weldguy »

I know your system can use raw or divided arc voltage and there ate setting associated with each that are important for thc to function properly. I would say that a setting has changed and your best to contact tracker and gave them
go through them with you.
dtdetail
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Re: THC issues

Post by dtdetail »

Well I feel like an idiot after getting off the phone with tracker.

When I moved my table from one side of the shop to another I removed the raw voltage cable (between power source and controller) so I it didn’t get pulled awkwardly.
Must have quickly checked the wiring diagram and plugged it back in without double checking, I had the AVC +/- plugged into the 24v+/- ports on the board.

Whoops, thanks for the help everyone.
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weldguy
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Re: THC issues

Post by weldguy »

Right on, easy fix. Those guys are good deal with, glad they got you fixed up.
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Re: THC issues

Post by adbuch »

dtdetail wrote: Thu Mar 09, 2023 8:26 pm Well I feel like an idiot after getting off the phone with tracker.

When I moved my table from one side of the shop to another I removed the raw voltage cable (between power source and controller) so I it didn’t get pulled awkwardly.
Must have quickly checked the wiring diagram and plugged it back in without double checking, I had the AVC +/- plugged into the 24v+/- ports on the board.

Whoops, thanks for the help everyone.
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