Hi all,
just added the THC and finished installing and ready to rock.
as the final check, I did the ground check per instruction.
There is no continuity between USB cable and machine but when I attach the clamp to machine, meter reads 61.5 kOhm. I’m also reading transient resistance reading between control box screw and machine in M Ohm range…
Unplug the plasma cutter to see if it goes away.
plasma cutter isn’t even connected to wall
What plasma cutter? Is the cable connector to the CNC port? Unplug the power to the control box and see if it disappears.
What happens when you unplug the Langmuir controller box? Next question: What else is on that steel rack that could be plugged in? My thought is that the service panel ground from your electrical system has created a ground loop.
There is still load when control box power is unplugged.
To be clear, it’s open only until the cutter clamp clamps to machine.
Nothing else is connected off the rack
I’ve basically gone down the list for checking ground. The load only shows when clamping to machine
Interesting. Have you tried the table yet? Somehow, the plasma cutter is setting up resistance to the table. It has to go through the plasma cutter connections. Either the torch is on and off, or the THC connection from the VMI. Oh well, we tried. Sorry, I couldn’t help.
The reason I asked about the metal rack is that anything plugged into the wall could be transferred a ground to the plasma cutter case.
I see. I can test it with cutter off the rack to rule that out. I will also take a pic of the internal connections to make sure I didnt mess up anything.
I have not tried running yet. With all the hard wiring, I want to tread carefully
No resistance when I unplug the vim with clamp on machine.
The red wire with yellow insulator is the raw voltage connection to clamp. The black wire with yellow insulator is the raw voltage connect to torch. The yellow insulator appears burnt because I tried melting it slightly to seal. The other small black running through vent is arc on/off
Others are factory connections.
could anyone confirm my connections are correct?
Yes, they look correct. BLACK to torch and RED to work clamp.
ok. Just wanted another set of eyes check. I would hate to see the thing blow up.
I’m also reading up on EMI topics. I’m afraid I will face similar issues down the road trying to get THC to work…
Try it. Put some water in it and cut out something when you’re ready.
Ok will do. How prone am I to the EMI issues that others had?
Don’t know till you try it. EMI is very rare. If you indeed have an issue, it will be with the VMI box.
THC live voltage test failed, 0V.
Called Langmuir, Raw voltage reading nominal
VIM output voltage nominal
didn’t wanna troubleshoot further so just shipped a new THC board.
Ensure that the front panel hole for the USB is enlarged before installing the new board. Hopefully, you will be on your way to happiness.
I’m not sure if I understand.
Make the hole larger so the USB won’t touch.
