PlasmaC torch starting problem (Solved with help from the famous three)

Clive S wrote: Yes I will do it again in the morning all the others were set at about 80 this one was at 10V.
the arc-ok wave is only 1 V and the arc-volt ripple looks like 20V

Ok I set it to 60v but fail to get a proper plot
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cut ok 60V

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failed plot this is after the first cut with the air still purging

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Ok cut

So it seems the maximum voltage this plasma can generate is about 230 volts. That is the value of the arc displayed during the failed cuts.

My guess is that on arc establishment of subsequent cuts (with air flowing) is that the blowback mechanism in the torch is shorted together (eg in arc starting mode). Remember that a blow back style torch creates the initial arc inside the torch with a dead short and then transfers it to the material. So the transfer of the arc does not occur for some reason.

I think the only thing you can do is service the torch and replace every consumable becasue by now are probably in a sad state.
If that does not work, it is how this particular machine is.

As an aside, its good to see the ArcOK being established at the correct time now so don't change any settings!

From these plots of good cuts, I see that there is a step down in the cutting voltage. I assume this is when the THC is enabled. Your arc voltage in Plasmac is set too low. It should be set on the naturally ocurring cut volts. I always sample the torch voltage to avoid this. Make sure the THC on delay is long enough for the voltage to reach the flat "plateau" observed in the charts before sampling.

From all these plots it seems to me that PlasmaC is doing what it should do.
My take is that the fails are reading the pilot arc and not the cutting arc.
It is interesting that the first cut is always good and the waveforms do show that.
From the plot below it looks to me like the voltage drops off before the arc ok and the torch on which would be correct behaviour on PlasmaC's part but it would be nice to confirm that with say a 1ms or 5ms division.

My guess is that on arc establishment of subsequent cuts (with air flowing) is that the blowback mechanism in the torch is shorted together (eg in arc starting mode). Remember that a blow back style torch creates the initial arc inside the torch with a dead short and then transfers it to the material. So the transfer of the arc does not occur for some reason.

I think the only thing you can do is service the torch and replace every consumable becasue by now are probably in a sad state.
If that does not work, it is how this particular machine is.

Rod. I don't think I have a blowback style of torch it is a pilot arc type I believe the blowback type has moving parts inside mine does not.

My torch is new this one:- parkertorchology.com/wp-content/uploads/2019/06/SCMP80R.pdf

phillc54 wrote: From all these plots it seems to me that PlasmaC is doing what it should do.
My take is that the fails are reading the pilot arc and not the cutting arc.
It is interesting that the first cut is always good and the waveforms do show that.
From the plot below it looks to me like the voltage drops off before the arc ok and the torch on which would be correct behaviour on PlasmaC's part but it would be nice to confirm that with say a 1ms or 5ms division.

Warning: Spoiler!

Phil thanks.
which signal should I change to 1ms or 5ms or are you asking for the Hoz display set from 200ms to 5ms

which signal should I change to 1ms or 5ms or are you asking for the Hoz display set from 200ms to 5ms

Yes, the horizontal thanks Clive so I can better see the timing of those signals.