Welding Arc Sound over Lines

Hi Gang, I have a situation with an Electronic Welding Machine when used provides the Arc sound over the Lines on all sets. This welder is used for aluminum welding. It only happens when the operator begins welding. When the machine is on and the operator is not welding nothing on the lines.

All 3 lines and grounding has been verified by the local telephone company as OK. Also, according to the customer an electrician has been in and verified all the grounding on premises is OK, including the welding machine.

We thought we isolated the trouble to a Cat3 wire cable tied to an electrical conduit that passed by and over the machine to a set approximately 30 ft away, using W/B. This cable also has a 24V paging speaker using the W/O & W/G.

I ran a Cat5E from the equipment to the phone, by passing the machine and keeping the speaker on the Cat3. I also doubled up on the pairs to the set using the W/B B/W for Tip and the W/O O/W for the Ring.

All thought to rectify this problem is appreciated.

Thanks Bob

Reply to
RBD
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What kind of system ? What make and model of welding machine ? Knowing what frequency the welder operates at may help tell how it is getting into the system. I've solved some weird noise problems, but a welding machine was not one of them! LOL Long way, disconnect one set at a time.

Reply to
KenW

Doubling up on the pairs like you did on the CAT5e cable was the wrong thing to do. The HF noise from the welder is not caused by excessive impedance or voltage drop, so doubling the copper won't help. But doubling the pairs the way you did essentially removes any twist between the tip and ring, and gives you no EMI rejection that would normally be provided by the twisted pair. In other words, doubling the pairs like that has done more harm than good.

Reply to
Telephonist

I would first make sure it is that cable giving you trouble, first I would disconnect the speaker and try it, then unplug the phone and try that then I would pull the cross at the frame and try that. If any of the above resolved the trouble I would first try and reroute the cable a different way or try and relocate the phone. The phone system itself doesn't reside in a room directly over the welder does it? As a last resort I would try a shielded cable grounded at both ends or not grounded (sometimes grounding the shield does more harm than good)

Reply to
John 807

This

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gave me a result to this:

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They specifically refer to welding

Reply to
GHTROUT

You still have to find HOW the noise is getting into the system.

Reply to
KenW

If identifying the problem takes resources beyond the $15 part, some people would say, "I'll spend $15 first - then if it does not work, I feel OK spending hours of time digging deeper"

Reply to
GHTROUT

If you get the filters, still got to figure out where to put them ! I hate when our customers don't have a maintance contract, but alot of them are pretty good about it. Still if it looks like a bad trouble, they get WARNED about it, and given the price of parts if necessary. I'm usually the RFI person at work.

Reply to
KenW

Reply to
Allen Kitts

Could be anywhere. Glad it's not my problem.

Reply to
KenW

First and foremost - you have a blatant CODE VIOLATION!!! How can you expect the cable to function properly when it was not even installed to code?

Reply to
Nortec in MN

O.K. what would be the code violation you speak of? With out being specific he may not be aware of it.

Reply to
John 807

I guess he means tied to a electrical conduit

Guess he doesn't work in the real world.

Reply to
KenW

Could be, although I've never heard of that as being a code violation. Now strapping to sprinkler mains and heads and gas, that's a different story all together.

John 807

Reply to
John 807

Yes - Per NEC, you cannot fasten to electrical conduit. This IS real world. The problem is too many installers have no idea what NEC is, let alone how to do a code complient installation. It is not difficult to properly install cable - the cabeler was likely just ignorant or lazy - we see it all the time.

It is because of these kinds of issues (as apparnet in the original post and KenW's comment) that many states now require an electrical license for low voltage and fiber.

Reply to
Nortec in MN

Good to know it is against code. I personally never strap to anybody elses stuff. Local 3 in N.Y. can get pretty nasty if you do. You are much better off running your own "J" hooks or drive rings for a couplea cables.

Reply to
John 807

We don't do it either but some old stuff is still around. Same with laying cable on a hung ceiling. Lots of that stuff still out there.

Reply to
KenW

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