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Author Topic: LPT cable is heating sometimes!! Please to help!  (Read 1278 times)

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LPT cable is heating sometimes!! Please to help!
« on: February 15, 2015, 04:44:39 AM »
Hello people,

I have finished my cnc machine, and every think it is ok, but i want to ask you why sometimes my LTP cable is heating! I didnt know why!
What about the ground wire that i have it on the supply power? I need to wire it somewhere on the machine?

Thanks so much!
Re: LPT cable is heating sometimes!! Please to help!
« Reply #1 on: February 15, 2015, 09:12:27 PM »
If your LPT cable is noticably heating you have a serious problem.
All your equipment must be grounded
The cutting table and the machine frame must be grounded. Your control electronics enclosure must be grounded. Your PC should be grounded through the power cord.
If the LPT cable is heating there must be many amps flowing through it, indicating a extremely unsafe condition at your end.
You have a short somewhere.











Re: LPT cable is heating sometimes!! Please to help!
« Reply #2 on: February 16, 2015, 01:41:55 AM »
Ok Grouchy,
First of all, thanks for your reply and your care about my machine.
Let's see what i have, first, if i didnt have ground to my machine, and on my table, and to my PC that i use to control the machine with Mach3, it's possiple that issues with the cable that heating due to the ground wire?

Offline Davek0974

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Re: LPT cable is heating sometimes!! Please to help!
« Reply #3 on: February 20, 2015, 08:02:34 AM »
I'm guessing this is plasma??

I fail to see how the current is getting into the LPT lead, they are generally isolated from the CNC table as its usually a floating system, grounded by the PC only.

Can you verify or check that there is no connection from the shell of the LPT connector to the frame of your table?
Unplug the lead from the PC and use a test meter to confirm that there is no connection.

It is very unusual to have a LPT lead grounded at the "noisy" end.

Then, is the plasma ground lead connected correctly?

Is the cable only heating when cutting or all the time?

If its all the time then there is a very serious fault somewhere.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives