Cut Votage Alarm help

Cut volage alarm thrown in the middle of cutting. I restarted the program and it started cutting fine like at first then at the same spot threw the same alarm. Any tips?! Thanks guys!

can you clarify a few things please…
by any chance are you using shielded consumbales?..
what plasma cutter are you using?
can you post a picture of your consumables please…

also what are your settings for the following
Cut height?
Pierce delay?

is there enough slack in your torch cable

have you checked all the hints provided in the error message…


A picture of the design and the spot where it lost voltage would help. If the torch crosses over an already cut area, it will lose the electrical connection and shut off.

Watching with interest. I have the same problem. Alot.

THC just starts raises the head until either the torch flames out. Or program stops with THC Error - voltage loss.

Restart program and error happens in same spot.

basic things to double check
clamp on material on clean location and clean clamp
ferrite choke on usb cable
coiled plasma lines …coiled lines on cables create electonic inteferance
laptop plugged in
a USB isolater can help…Langmnuir has some if you ask
torch cable to tight above table

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Work clamp - got it
Ferrite Choke - got it x 2
Coiled lines - all laid out when using the 50’. The 25’ just reaches the parking spot of the 100a
Laptop - plugged in or on battery it does not matter
USB Isolator, will try the hub next
Torch cable - 50’ in cable chain, 25’ plenty of slack.

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Does the table pass the ohm’s test? Grounding Considerations

Due to the fact that THC signal voltages can be sensitive, it is important to make sure that USB ground is not connected to the machine frame. This can result in lower than expected voltage readings which can negatively affect performance. Before cutting, we recommend using a multi-meter or continuity tester to check for continuity between the USB plug shell and the gantry tube as shown below. Before performing this test, be sure that:

  • Machine Power cord is plugged into the electronics enclosure.
  • USB Cable is plugged into the electronics enclosure and your powered-on computer.
  • Plasma Cutter is connected to THC VIM and electronics enclosure.
  • Work clamp is connected to the machine frame.
  • If you are using a laptop stand, make sure your laptop is sitting on it while performing this test. (Its possible the laptop stand fasteners can conduct through your laptop)

Continuity Test

If you detect continuity in this test, please message us at Langmuir Systems Support for steps to resolve.


I am pretty sure that is what is happening. I will try and upload a photo. But it seems to be going over an already cut area and shutting off.