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Author Topic: Any better Rack fan options  (Read 5698 times)

Martin Bilecki

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Any better Rack fan options
« on: September 06, 2011, 06:00:06 PM »

  Are there any better options for standard rack 4.5" Middle Atlantic rack fans ????

 I have had more than a few poop out this year ???

 Thanks in advance
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Riley Casey

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John Livings

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Re: Any better Rack fan options
« Reply #2 on: September 07, 2011, 06:08:47 PM »

In addition to what Riley posted (Nice and Quiet, 120V) we have used Mid-Atlantic Blanks (2, 3, 4 fans) and went to a local parts store (Fry's) and bought some 100 MM , 12 vdc Quiet computer fans (4 for $20.00).

I don't know if it is less expensive to do it yourself or just buy everything already made.

My understanding is that "Sleeve" bearings are quieter and "Ball" bearings last longer.

Regards,  John

« Last Edit: September 07, 2011, 06:11:37 PM by John Livings »
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Bob Leonard

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Re: Any better Rack fan options
« Reply #3 on: September 08, 2011, 12:53:05 AM »

Actually it's the blade design and RPM that determine if the fan is quiet or not. Ball bearing fans will last longer and will be just as quiet as fans that use bronze bearings until they start to fail, at which time they produce a high pitched whine.
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BOSTON STRONG........
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John Livings

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Re: Any better Rack fan options
« Reply #4 on: September 08, 2011, 03:48:02 AM »

Actually it's the blade design and RPM that determine if the fan is quiet or not. Ball bearing fans will last longer and will be just as quiet as fans that use bronze bearings until they start to fail, at which time they produce a high pitched whine.

Hi Bob, Thanks for the input, I guess you can't believe everything you read;

http://www.comairrotron.com/cooling_fan_noise.shtml

As I read this,  the Aerodynamic Noise remains the same if the RPM and Fan Blade are the same and the RPM is not High (1000-1500 RPM), The link states the sleeve bearing is quieter.

One could agree that a fan spinning at 5,000 - 10,000 RPM would create so much Aerodynamic Noise (Maybe 95%+ of the total noise) that the choice of bearings may not matter.

Just my thoughts.

Regards,  John 
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Bob Leonard

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Re: Any better Rack fan options
« Reply #5 on: September 08, 2011, 10:54:34 AM »

Pretty good info from that company John, but I'm basing my reply on the literally thousands of fans I work around, or may have replaced in some cases. The many large data centers I work in every day often have sound levels that make even close conversation impractical. I might even agree with the fact that a ball bearing can eventually become a noise factor. But any perceived noise from a new fan will not be attributed to the bearings, either bronze sleeve or ball. The noise factor is going to be a result of blade design, fan size (maybe), and fan speed.

Here's a link that may interest you.

http://www.rackfans.com/modules.php?name=Pro_Guide
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BOSTON STRONG........
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John Livings

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Re: Any better Rack fan options
« Reply #6 on: September 08, 2011, 02:57:36 PM »

Hi Bob,

Thanks for taking time to respond, I agree that Empirical knowledge is almost always the best real world test.

Regards,  John
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Bob Charest

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Re: Any better Rack fan options
« Reply #7 on: September 08, 2011, 03:04:32 PM »

Pretty good info from that company John, but I'm basing my reply on the literally thousands of fans I work around, or may have replaced in some cases. The many large data centers I work in every day often have sound levels that make even close conversation impractical. I might even agree with the fact that a ball bearing can eventually become a noise factor. But any perceived noise from a new fan will not be attributed to the bearings, either bronze sleeve or ball. The noise factor is going to be a result of blade design, fan size (maybe), and fan speed.

Here's a link that may interest you.

http://www.rackfans.com/modules.php?name=Pro_Guide
Bob, thanks for the link! I like a fan that can get as low as 9db  :) I did my own fans in our rack and used a number of 12v fans but under-powered them (with 6v I think) so they ran slower and much quieter. They move all the air we need and are silent.
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Greg Bellotte

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Re: Any better Rack fan options
« Reply #8 on: September 09, 2011, 12:03:13 PM »

ok don't laugh, but i've been using units from pyle, the pfn31 or 41. they still fail after a while like everything else, but at $40-50 i consider them disposable.
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timing is everything...

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Ricky Lighthall

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Re: Any better Rack fan options
« Reply #9 on: September 10, 2011, 11:23:45 PM »

Be careful with under-powering fans.  They will stall or fail to start at all if supply voltage is too low. 
This value is often found on the datasheets.  There are circuits to ramp down the fan after power up on the web if needed.
Also, surplus is your friend for some of those expensive fans.
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Bob Charest

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Re: Any better Rack fan options
« Reply #10 on: September 11, 2011, 08:03:57 PM »

Be careful with under-powering fans.  They will stall or fail to start at all if supply voltage is too low. 
This value is often found on the datasheets.  There are circuits to ramp down the fan after power up on the web if needed.
Also, surplus is your friend for some of those expensive fans.
Agreed - Fortunately, I found a power supply sufficiently near the design voltage but with the drop in revolutions and noise. They've been running for over two years now, so it worked (and works) for me. It's a sweet spot that needs to be hit if you go that route.

I only did it because I couldn't find something quiet enough for me.

Best regards,
Bob Charest
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Re: Any better Rack fan options
« Reply #10 on: September 11, 2011, 08:03:57 PM »


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