UPS vibration and sound proofing

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D'oh!
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UPS vibration and sound proofing

Post by D'oh! » Mon Apr 20, 2009 7:20 am

I have a 2U APC UPS sitting on the floor of free standing rack. UPS transformer produces constant low level buzzing which is annoying but it's the vibration that drives me nuts.

Two questions:

1. I thought of putting insulation foam to help absorb vibration but don't know what's it called in professional world (rubber? neoprene? anything else?), what's the best one for the job (UPS weighs 60kg) and where to buy one. Any suggestions? i'm in the UK.


2. What is the best way to safely sound deaden the UPS without opening it provided I don't want to shell out £500 for 4U cabinet just to host UPS. I had experience with acoustic cabinets (have 12U one) and they are good but I just can't justify the price right now. Any ideas here?

many thanks

D'oh!
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Post by D'oh! » Wed Apr 22, 2009 6:36 am

This is truly silent forum. Anybody?

CA_Steve
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Post by CA_Steve » Wed Apr 22, 2009 7:34 am

I don't know a damn thing about racks...so please bear with some stupid questions...

When you say the supplies are sitting "on the floor" of the rack and it's the vibration that's annoying you...

Is it transmitted noise via direct contact of the supplies with the metal rack? (If you set the supply on some phone books, does the noise go away/reduce)? If so, just go low tech to isolate the supply from the rack. Maybe set the supplies on a piece of thick plywood with some soft rubber on both sides. The softer the better, BUT, you still want the bottom of the UPS to have clearance for airflow.

The next step would be to build up/insulate the sides of the rack. Get high mass vinyl floor tiles and glue them to the inside of the rack. The heavier the better. That'll help reduce vibration.

MikeC
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Post by MikeC » Wed Apr 22, 2009 7:37 am

60kg UPS units, eh? And you say it's the vibes that bother you more than the buzzing? I'd want to know more details. Like does the vibration cause the floor to hum/shake? Do you have any idea what frequency it is at? I'm guessing it's at 60Hz -- or 50Hz depending on your AC.

I'd experiment first with cheap simple things. Like a 3/4" board a bit bigger than the UPS units (maybe both) with foam one side. Put the board/foam between the UPS and the floor with the foam on the floor. The thickness of the foam -- thick enough so when the weight is on it, it compresses, but not too much. It should still have give when you press down on the UPS. The exact type of foam doesn't matter. You're looking for some mechanical damping/decoupling from the floor. When you find the right combo, glue the foam to the board.

That should help with the vibrations.

To reduce the airborne noise, I'd use a box lined with some foam on the inside to place over the whole thing -- and it should touch nothing but the floor. You could use something like a big plastic bin or make a wood box. You may need to put some holes in it to let heat escape. Make the holes only on one side, and face that side away from you. What type of foam? Here, things like Acoustipack or the stuff from Nexus, neither of which are cheap, would probably be best. They combine a mass damping layer to keep the panel from vibrating and a softer foam to absorb airborne noise.

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Post by MikeC » Wed Apr 22, 2009 7:43 am

CA_Steve and I must have been typingat the same time... :)

After I read his post, I realized I misread -- floor of the rack, not the floor. Hmmm. Then, I'd say you want to remove the "floor" panel of the rack and place the UPS units directly on the floor -- with the board+foam between. This will keep the vibes from getting into the rack. Then enclose it using whatever is practical/available to you, keeping in mind the basic concept of dense, panel-damped and softer foam lined on the inside.

CA_Steve
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Post by CA_Steve » Wed Apr 22, 2009 7:46 am

yeah - I type slow before that 2nd cup of coffee. :D

d-oh
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A picture is worth a thousand words..

Post by d-oh » Thu Apr 23, 2009 2:34 am

Thanks for the input guys. Here's the setup picture (2 posts below). Yes vibration occurs directly between UPS and "floor" or the bottom plywood shelf of the rack if you wish. As one can see it is not a cabinet as such but two pole rack so no fabrications are really available that would not affect the aesthetic side of things. I would want as elegant solutions as possible of course. So far buying a XRackPro 4U cabinet seems like a good idea but too pricey to start with otherwise I wouldn't bother. Building a plywood box for UPS may not be as easy considering the weight of the battery. I guess I could order some custom made 2U enclosure that would need to be deadened with foam and equipped with a fan at the back but then again the cost would probably come close to XRackPro's one and the look would never be as close. Since there's no easy way out of this I would probably get a rubber sheet to lay underneath and let it buzz! Thanks to everyone.

d-oh
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Post by d-oh » Thu Apr 23, 2009 2:35 am

My other account can't post any new messages :- an SQL error occurs so can mods please kill it?

d-oh
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Post by d-oh » Thu Apr 23, 2009 2:36 am

here's the picture (in the next post.)

d-oh
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Post by d-oh » Thu Apr 23, 2009 2:37 am

Image

CA_Steve
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Post by CA_Steve » Thu Apr 23, 2009 6:13 am

Yowsa...are those metal feet on that PC?

d-oh
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Post by d-oh » Thu Apr 23, 2009 8:19 am

No they are rubber feet with shiny plastic surrounds. The server itself is no cause of vibration or noise as there are no moving parts except for 2 x 120mm slow spinning fans.

lm
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Post by lm » Thu Apr 23, 2009 10:14 am

First thing to try is to move that UPS directly on the floor.

d-oh
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Post by d-oh » Fri May 01, 2009 9:59 am

I ended up buying a mat that took a little care of vibration issues. I would probably have to buy the darn cabinet..

ps. lm, i can't.

lm
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Post by lm » Fri May 01, 2009 12:07 pm

Can't you even try that for a while for diagnostic purposes? To see what the effect would be like?

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