THC is an intricate system, understanding how THC functions and knowing the context of what you are doing when wiring THC are paramount to doing it correctly and safely. We highly recommend reading the whole THC user guide before wiring the THC function and attempting to use THC. Click here to be taken to the THC user guide.
If your plasma cutter does not have a CNC Port with an integrated 50:1 voltage divider, you will need to tap into the raw voltage inside your plasma cutter in order to connect to the VIM box. The VIM box has an internal voltage divider and filtering network at the raw voltage inputs in order to output a low voltage signal to the CNC electronics enclosure for processing by the THC electronics module. Every plasma cutter has two high voltage main terminals; the plasma torch electrode (negative) and the work clamp return (positive). Each Langmuir Systems THC kit includes a pair of red and black Raw Voltage Pigtail Cables that are rated for CATIII 1000V for connecting to these plasma terminals. One end of these cables is a 4mm high voltage male banana connector that plugs into the corresponding color socket on the top of the VIM box. The other end of these cables is stripped as a pigtail for connecting to the raw plasma terminals inside or outside your plasma cutter by a suitable connection method.
Each plasma cutter model is different and it will be necessary to consult with your manufacturer or a qualified technician in order to determine the best hookup points for the Raw Voltage Pigtail Cables on your plasma cutter. Some plasma cutter electronics boards have convenient ring terminal mounting points on the boards that connect the positive (work) and negative (electrode) voltage lines to the Work Clamp and Torch hookup ports. Connecting to these terminals can be accomplished by crimping on ring terminals to the provided Raw Voltage Pigtail Cables and affixing these ring terminals over the existing ring terminals. If you are unsure where your positive and negative plasma terminals are inside the cutter, a general rule of thumb is to look at the work clamp hook up and the torch hook up on the inside front panel of the cutter. If you trace where these ports hook back up to the control board it will be easier to find a convenient location for tapping into the raw plasma voltage. Some plasma cutters may be successfully wired without having to open up the the chassis by making connections at the front of the machine where the work clamp and torch connect. In addition, some manufacturers will publish instructions for attaching to the Raw Arc Voltage inside the plasma cutter. For example, instructions for the Hypertherm 45XP can be found here.
When making connections to the main plasma terminals inside the cutter, it is important to ensure that the cables do not get pinched by the cover when reinstalling. It is highly recommended to feed these cables through a suitable hole in the cover or chassis of the cutter when installing to prevent severance of these high voltage cables. Any connections made to the main plasma terminals of your cutter must be properly insulated and protected from adjacent components and for strain relief.