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Electrical Interference specifications ?

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by richard h 1 view

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Does anyone have any idea or can po9nt me to where to find specifications or minimal distances between equipemnt (servers/routers/data cables) and big UPS systems? I'm trying to solve a proximity issue with a 50kva ups about three feet from a server rack.

10 replies

by dmiles

The following site may be of help
1)www.arrl.org/tis/info/rfigen.html
2)www.geocities.com

by richard h

That's more of the same stuff I had been looking at. Searches either bring up sites on supplying power to servers or radio interference from either servers themselves or big nearby transmitters.

by thechas

Are you sure that it is coupled (radiated) noise, and not line noise?

One way to check is to get ahold of some mu-metal and sheild some of the affected devices.
One source is Perfection Mica Corporation.

I haven't looked for their web address, but Compliance Engineering magazine is dedicated to all manner of electrical and electronic noise and safety issues.
Their annual guide issue is a treasure trove of EMI EMF and ESD information.

by richard h

Nothing is installed yet. I was trying to head off problems before they occur. I don't want to have to completely remodel a working computer room because I find out 2 months down the road that all my files are corrupted or the source of intermittent server abends is the UPS.

by jigash

Basically, as per the standard, the minimum distance between VOICE & DATA is 6 inch. While the Distance between VOICE, DATA & Powerline should be atleast a feet.
Moreover the power cables & Data cables should be in a different conduits.
Please refer to ICRA & IEEE standards for the same.

by richard h

I searched IEEE (ICRA keeps talking about conference agendas, no information I've found). IEEE is beyond me since I am not an electrical engineer. Most discussions I found related to EMI from power, proscessors, or cabling. Nothing I could use since I don't know the formulas mentioned nor the aspects of UPS cabinetry and sheilding.

by richard h

Point value changed by question poster.

Also, UPS rating is 150kva not the 50kva originally mentioned.

by wlbowers

You didn't mention the brand of UPS. I did
some evaluating of major brands for some
medical installations and found one unit that
just tore up channel 3. I had the OEM
engineers scratching their heads as they
waved portable tv arou nd the unit. I never
found out what the problem was. I just
scratched them off the list.

Direct contact some of the majors. I use APC.
They will help you design the system. Their
units are Jake.

Good Luck Lee

by richard h

Thanks for the reply.

Been there - done that - the T-Shirt didn't fit!

They (Leibert, APC and some Canadian company I forgot the name of) said they have no evidence and no data supporting any argument you want to make about interference. Theyjust simply have absolutely no data on the topic at all. My immediate problem has been solved since when they moved the unit in it's final resting place on the second floor the floor started to buckle. I was actually looking at the sag in the floorwhile the engineer that designed the building was telling me to trust him on the interference issue because he knew what he was talking about!

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