PlasmaC Voltage Divider

Is this resistor better with 0,6w ?

www.reichelt.de/de/de/shop/produkt/wider...207_0_6_w_0_1_-12752

2 x 2watt is correct I believe

Much better.
 

Thanks.

I soldered both resistors in the + und - Line inside the plasma source and also connected the 2 torch-start pins of the plasma-source with the Spindle enable + and Spindle enable - -Pin of the Mesa 7i76e-board.

When I power up the plasmacutter it instantly fires although the torch is not activated in plasmac. When I remove the 2 wires from spindle enable +- then the plasmacutter doesn't start when powered up.

When I measure between s-en+ and e-en- with a multimeter there is no connection but the plasma fires when started. Maybe somebody has an idea ? Do I need an additional relays ? With the hypertherm powermax 1000 G3 on the same mesa-card this didn't happen ?

Maybe sb has an Idea?

Sounds like you may have the spindle ENA polarity backwards.
 

I tried it again without changing anything and the plasmacutter started without firing at startup. Then I loaded the materal and tried to make a cut through 10mm mild steel. The torch fired, but the machine didn't move. And the torch went on and of a few times.
Why does that happen ? And why doesn't the machine move ?

Sounds like it did not get an Arc OK signal.  

The criteria is different depending what Mode you are using:

linuxcnc.org/docs/devel/html/plasma/qtplasmac.html#plasma:modes

I use mode 0.
I connected the divided arc voltage to the thcad and now the machine moves when it cuts, but it also goes on and of very often. You can see it here:



Could it also be a grounding-problem as the part is very small and I attached the ground clamp to the aluminium box where a steel grid is inside.

And why does it dive down in the middle of the part ? It seems to stop when the float switch is activated. 

Change pierce delay to something much smaller, like 0.2 for up to 5mm thick, 0 for up to 2mm and 0.5 for 5-10mm, etc.
Also show us other settings and the main screen while cutting.

As Tommy said, it's difficult to say without seeing all of your settings and such.  The sputtering is likely a connection issue of some sort, but the dive looked to me like there's something set incorrectly.  Looked like a move to cut height that was in the part rather than above the part.