back to the 75kVA in the Toilet Room

[adams1]

So this unit was hung below the ceiling in a single use Toilet Room. It was inspected no problems. Client wants to move the unit above the ceiling (staff are scared), remove the ceiling (required by Code) and treat the unit with a cover to mitigate the vibration. Any safe and popular options here that seem worthwhile chasing? The bottom of the unit will be around 13' AFF. Thanks

 

[waross]

Check with the inspection department. Take out a permit and have the new installation re-inspected.
I know that this seems to be a little much, but it will assure that you do not inadvertently void or otherwise negatively impact the insurance on the building.
respectfully

 

[BJC]

If you cover it you may cause it to run hotter and in turn decrease in't rating. The reason transformer installations over ceilings is because of overheating concerns. Waross is right, get it blessed by the inspector with any covering on it. If he says "no" start looking for a quite transformer.

 

[dpc]

I'm not sure the cover is going to help much with vibration. There are some rubber products available for the transformer to sit on to minimize transfer of vibration.

These dry-type transformer put out a lot of heat - I would check installation instruction on how much air space is required around the unit.

How are you supporting the transformer?

 

[itsmoked]

And all the reasons we counseled putting the xformer outside are coming home to roost...

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[BJC]

Transformers are "easy" to make sound cancellation systems for. I think you just record the sound and play it back 180 degrees out of phase.

 

[Skogsgurra]

That's a nice theory, BJC - and very practical, too...

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[BJC]

Skogsgurra
I have seen it done for larger distrubition transformers in surburban areas. We tried to get it done for a diesel generator at a plant near some homes. The consultant had never done it but wanted to. I think he wanted us to pay for him to do some research and write a paper. The diesel has a very complex sound spectrum while a tranfromer is all 60 cycles and harmonics thereof.
They do make ear protection for shooting that produce cancellating sounds for gunshots so a 75 KVA transfrormer should be a piece of cake.

 

[MikeHalloran]

I have no idea what it's actually called or where to get it, but I've seen sound- absorbing louver panels in yacht engine rooms; ventilation air passes through readily, sound does not. Apparently it comes as an assembly that's fitted into a bulkhead like a prehung window. Maybe it would be code- acceptable as a 'ceiling' in the toilet.

Inside the metal frame are alternating stripes of open air and dark colored foam, probably plastic. The openings are 1..2" in their shortest dimension, and the foam between them is similarly proportioned. Depth through the bulkhead is >4".

These are not quite what I had in mind, but the geometry is similar:

http://www.acousticalsurfaces.com/hvac/silent_louver.htm?d=26

Mike Halloran
Pembroke Pines, FL, USA

 

[EEJaime]

The simplest thing to do when you relocate the transformer is to have it checked out completely, make sure all internal connections between the coils and frame and all other bolted parts are tight and secure. Tighten all exterior skin panels.

Then to isolate it from transferring vibration to the building/space, mount it to a solidly made steel frame. Mount the transformer to the frame and the frame to the structure with sound and vibration absorbing "sandwich pads",(Type 'FP') and/or spring hanger,(Type 'CH') devices, by "CalDyn", (California Dynamics-

http://www.caldyn.com).

There will always be some hum, but it can be minimized without installing an extravagant and experimental sound cancellation system. Remember, it's a toilet room. Pipe in some Muzak!

 

[Skogsgurra]

Yes, BJC. I have even worked with anti-phase devices for an ear protection company (built into the "cups"). Atlas Copco has also used the principle on some of their compressors. But there, you have a well-defined geometry and sound transmission via air. A transformer usually doesn't emit much sound via air. Most of it via the vibrations in the building itself. And that will not be possible to compensate for with an active anti-phase system.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[TheBlacksmith]

At one point Volvo was experimenting with active noise cancelation for city buses. They had a demonstrator with a rear mounted 12 liter engine with straight pipes after the turbo and it was virtually silent. Don't know what became of it.