They’re supposed to help with the electromagnetic interference in the USB which corrupts data.
I do get some freezes from time to time but I also do forget to unplug my laptop from time to time so I’m not sure if the emi is coming through the power cable to the laptop or through the usb?
An APC or uninterrupted power supply might help if it’s on the power supply side?
Usually when I get a freeze the machine will keep cutting and running the program I just won’t be able to interact with fire control anymore to pause it.
I’m not knowledgeable enough to make a determination but this is what I found. Maybe someone on the forum can tell us what it all means in the context of our tools?
“Model UH401-2KV is a compact isolator that packs a powerful punch against electrical noise, surges and spikes with 2 kV isolation. Protect expensive PCs and equipment from damaging electrical storms, power surges and other high EMI/RFI disturbances. This isolation barrier eliminates ground loops which are disruptive in measurement applications. Suitable for 12 Mbps full-speed USB devices. The isolator is USB bus-powered and provides up to 100mA of current to attached downstream devices when attached to a full-power (500 mA) USB host port. USB cable included. Note: Data rate is preconfigured at the factory. High speed (480 Mbps) cannot be isolated with existing technology.”
Drive a 8ft copper ground rod into the earth. Connect all motors with 12Gauge wire or copper braided wire to ground bar. Connect positive work piece lead to ground bar.
Every thing BUT the Langmuir box and your computer. ENSURE YOUR COMPUTER AND LANGMUIR CONTROL BOX HAVE NO CONTINUITY AT ALL TO THE TABLE FRAME AND MOTORS. Take multi meter from table to outside shield on printer cable from laptop. EMAIL ME IF YOU NEED HELP. YOUR PROBLEM WILL BE GONE FOREVER…
Do not try to use grounding system from service panel. Your earth grounding for table will run into the rod you drove into the earth.
The grounding system will greatly reducer EMI and RF interfaces. There are lots of videos on YouTube about the subject. The answer to your question is that they are not the same but produce the same problems with electronic equipment.
Your old enough to remember antenna TV. People that had a high voltage tower from the power company in a nearby location would have enough EMI or RF energy to make it impossible to get or watch TV back then. Same deal.
Read the hypertherm website on EMI.
Most people will never get enough of it around their plasma cutter to effect it. The first thing that needs to be done is to make sure that the Langmuir control box and the table are not connected through the laptop. It may be as easy as adding an old school two prong no ground adapter to the laptop/computer power supply. Your table must pass this test to ever work correctly.
See the Langmuir instructions on continuity test on their assembly sheet.
You do realize that the Work Lead is the Current Sense lead that the Plasma Cutter uses as feedback for the current going into your work. The way I visualize the circuit, one should never ground the work lead. Maybe my buddy @mechanic416 can chime in on this matter.
Yes sir.
Plasma voltage is DC not AC. That being said it is the main reason you don’t hook up to the AC service ground.
I know it goes against all common theory but it works.
Most people will never have the problem. But depending on the plasma cutters shielding and construction this will haunt some.
The whole plasma theory comes from Langmuir the scientist . Common lightning is DC voltage at least till Mr Tesla came up with AC theory that pissed off Thomas Edison.
Please make sure it does not touch. Some guys use a block of plastic or wood. This is very important. Those washers should be stepped to fit in the large holes in the control box. They sort of snap in. Then the screws are isolated.
I’m pretty sure your ‘solution’ won’t work. The insulation will be torn away by the threads. I would use a Nylon Flange washer where the bushing of the flange fits inside the hole of the Control Box - if I had a FireControl system.
A better solution is to not have the electronics grounded in the first place, but too late for that one…
