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Old 05-19-2020, 07:44 AM   #1
cook
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Default Silent APC UPS?

My old BackUPS LS 500 is silent. When it is not running on battery, there is no hum or slight buzz at all -- nothing. I like that.

I just got a BackUPS CS 350, hoping it would be silent too, but it has a slight hum/buzz to it. When the room is very quite, you can hear it from 10 feet away.

Does anyone know of a good brand of UPS that is silent, and around 300-500VA?
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Old 05-20-2020, 07:02 AM   #2
cook
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Default Re: Silent APC UPS?

Just a quick update... My LS 500 actually does make the faintest hum, but you can only hear it when you ear is right up next to it.
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Old 05-20-2020, 07:38 AM   #3
eccerr0r
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Default Re: Silent APC UPS?

and I thought I was being over sensitive when I can't stand Delta fans...

/me goes back to listening to the computer fan cacophony. Sans Delta fans however.
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Old 05-20-2020, 08:31 AM   #4
CapLeaker
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Default Re: Silent APC UPS?

my smt-750 is totally silent.
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Old 05-21-2020, 05:32 AM   #5
cook
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Default Re: Silent APC UPS?

Thanks for the feedback on the 750.

I have found out that my cs-350 is much quieter when sitting on carpet vs. tile. And that makes a lot of sense because carpet absorbs a ton of sound, yet it still surprised me how much difference it made. I can live with it now.
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Old 05-21-2020, 03:32 PM   #6
sam_sam_sam
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Default Re: Silent APC UPS?

Dose it have vents on the of this UPS supply
__________________
9 PC LCD Monitor
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30 Desk Top Switching Power Supply
10 Battery Charger Switching Power Supply for Power Tool
6 18v Lithium Battery Power Boards for Tool Battery Packs
1 XBox 360 Switching Power Supply and M Board
25 Servo Drives 220/460 3 Phase
6 De-soldering Station Switching Power Supply 1 Power Supply
1 Dell Mother Board
15 Computer Power Supply
1 HP Printer Supply & Control Board * lighting finished it *


These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
2 Hem Saw Computer Stack Board

All of these had CAPs POOF
All of the mosfet that are taken out by bad caps
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Old 05-24-2020, 07:48 AM   #7
cook
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Default Re: Silent APC UPS?

Quote:
Originally Posted by sam_sam_sam View Post
Dose it have vents on the of this UPS supply
Yes, it has vents. But the carpet is not blocking them.

I think the sound mostly comes out of the top vents. Also, when I squeeze the side of the UPS (which is plastic), the sound changes a bit, and is a bit quieter.
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Old 05-25-2020, 11:06 AM   #8
sam_sam_sam
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Default Re: Silent APC UPS?

Them cheap plastic cases again
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