Fan bearing chatter Question

DJS · Post by **DJS** » Wed Feb 23, 2005 9:55 pm

About a month ago I purchased 2 Panaflo FBA12G12H 120mm X 38mm fans with rpm monitoring from sidewinder computers last month, which I installed and had no problems. Last week I installed a Matrix Orbital MX432 which is able to control fan speeds automatically. Well my problem is when the Panaflo's get a reduction in speed they both start to produce an extremely annoying clatter sound, which gets louder with the lower the voltage gets. By loud i mean hear it across the room and from other rooms. I understand that there is something called bearing chatter, but is it supposed to be that loud? Now these Panaflo's do not have regular bearings but Hydrowave bearings as shown in this:

http://www.panasonic.com/industrial/app ... atures.pdf

Could the Hydrowave bearings not work properly at lower RPM's?
I know that panaflo's are good quality, but i spent alot of money on these fans and if they are not going to be silent when i adjust to lower voltages then maybe I need to get some different fans

. Has anyone else experience this, or is it possible that i recieved a bad batch of fans?

Bluefront · Post by **Bluefront** » Wed Feb 23, 2005 10:14 pm

Welcome to SPCR..... have fun here, get frustrated here, maybe learn something.

The fans you mention do not have a good reputation for quiet running, no matter what the rpm. Most of the really quiet fans have sleeve bearings, with less tendency to have bearing noise, but a shorter life-span.

Look into a Nexus or Yate Loon fan for quiet running, with Globe sleeve bearing fans a close second.

Don't know about your fan controller, but some use PWM, pulse width modulation, to control fan speed. This works well but induces noise to certain fans....some worse than others. Globe fans handle PWM very well, better than the Yate Loons (Nexus...same brand).

Finding a good quiet fan can be difficult, because in a large batch of identical fans, only a few will be really quiet.

burcakb · Post by **burcakb** » Thu Feb 24, 2005 6:43 am

Could the Hydrowave bearings not work properly at lower RPM's?

There's one problem for you. 120mm Panaflo's are NOT Hydrowave. It seems the Hydrowave technology cannot handle the large weight/torque required in large fans.

That is why, even before the nexus, while the Panaflos were the reference fans for 80mm and 92mm, the 120mm reference fan quickly became the Globe.

DJS · Post by **DJS** » Thu Feb 24, 2005 11:08 pm

Hey Guys thanks for your response.

On the Hydro bearing issue i thought i read on one of thier fact sheets that some of the 120mm were with hydro bearings:

http://www.panasonic.com/industrial/app ... fba12g.pdf

and the product numbering also states that it should be a hydro bearing:

http://www.panasonic.com/industrial/app ... common.pdf

my fans are FBA12G12HBX, so in the third space i believe an A is for Hydro Bearing and a K for a ball bearing.

But i have the same concern as you that the bigger the fan or slower the rotation the hydrobearing might not work properly. I will test some more fans shortly and find out if indeed it is the fans or that my fan controller (which does use PWM) is the problem.

burcakb · Post by **burcakb** » Fri Feb 25, 2005 12:33 am

hmm, you're right FBA is hydrowave. I was SO sure of the fact. Maybe I got mixed up with the FBK version usually referenced here.

You might want to check out this post though:

Dorothy's take on fan noise

If you further go and read ALL posts by jafb2000 (available through her profile) you'll get way more info on fans & Panaflos than you'll ever want

It seems the MX4 series does use PWM for fan control. There's supposed to be some software to adjust PWM frequency although I couldn't find a reference at the MO site. That may allow you tune out the clatter - maybe.

frankgehry · Post by **frankgehry** » Fri Feb 25, 2005 1:19 am

DJS,

Have you mounted the fans with any kind of damping material like soft rubber washers or special mounting posts. Since the fans were quiet at first I don't know if this would make a difference, but you might try holding the fans in your hand to eliminate any case vibration. What kind of case do you have? I find it strange that both fans have developed this problem. If they were quiet at first I assume they were working ok. Then they both developed the same problem or became defective at the same time. Wierd. - FG

The guy at sidewinders in very nice - I believe his name is Gary. I would casually mention that you asked about the problem on the spcr forum, but haven't been able to fix them, and after all it does have rpm sensing and it is supposed to run slow and quiet. I wasn't aware that the 120's are not as good as the smaller panaflos, but they still must be pretty good.