Panaflo FBA12G12U (-1BX) RPM Sensor

[I.M.O.G.]

So I have 4 of these, which I used to use with LN2 to keep parts of the motherboard from freezing over... They include a 4 pin molex for power that connects directly to the PSU, but they also have a separate lead for RPM sensing which goes to the mobo header.

I've never used anything to control my fans - I either used quiet ones, or I let them roar. Now I'd like to repurpose these Panaflo's, but they can be heard upstairs when running in the living room... If I use my Mobo's features to limit fan speed, will that work with this RPM sensor? Or does the sensor only report RPM, and not enable any fan speed control?

Essentially, I'm not sure if I understand the basics of fan speed control. I think it works like this - if you have a normal 3 pin plug that goes to the mobo fan header, the yellow wire is the sensor wire, which tells the mobo how fast the fan is going then the mobo moderates how much voltage it gives the fan to control its speed. If you have a 4 pin plug that goes to the mobo fan header, it's a PWM fan and its speed is controlled through signaling in the motor.

Thanks for any input. If I'm on track with the basics, I'll probably just do a 5V mod and see how that works for me.

 

[inVain]

for a 3 wire fan,
you can't control anything with the motherboard, if the fan draw power straight from the PSU's molex header.
the 3rd wire is simply reporting the RPM.

just do the 5v mod.
it's super easy, and you might love their performance

 

[Operant]

Another option to consider would be soldering up a circuit with a potentiometer to get the variable speed you want. Depends if you want the option to change their RPMs or if you just want a fixed setting.

 

[hokiealumnus]

3-pin fans are voltage controlled. You'll need to reduce the DC voltage (red & black wires) to reduce the speeds of those fans. Yellow is for reporting only. Some motherboards can control voltage via BIOS or software. If they can, they often only do so on certain ports. The easiest way to find out is to install a 3-pin fan plug and hook it up to the board to find out whether you have any control. Odds are it will just spin at full speed, but it might be worth a try.

If it doesn't, you can either get a fan controller to have control over them, or do the 7V or 5V mod via MOLEX connector (see this thread for example with pictures). This may be a better option for you if you don't have spare 3-pin fan plugs on hand. Keep in mind that these fans sometimes require more than 5V to spin up. It depends on the fan and its age; some will, some won't. I know I've got my three panaflos set at ~6.5V. They're not silent, but it starts them up and they're very quiet.

You can also put a resistor in-line to reduce the voltage but you probably don't have them on hand.

 

[I.M.O.G.]

I went with the 5V mod from that thread and it quieted them down a lot. I also compared with 7V but both 5V and 7V on these fans show the same motor noise and 5V had less fan noise so I went with that. The motor noise is more of a pulsing click though low pitched, and isn't nearly as much of an issue as the whooshing air movement at 12V.

I started folding two days ago since I installed the GTX 760 in my HTPC - it didn't actually fit in the HTPC case as it was too tall, but I just left off the top cover as only the front panel of the case can be seen inside the TV stand. With folding however, and the HTPC being almost fanless, it became an oven in the TV stand pretty quickly with the PSU being almost burning hot to the touch and even the HDD rack inside the case getting extremely warm - even on 5V two of these fans fixed that right up. The back of the HTPC compartment is open with about 8 inches to the wall behind it, so I have one fan exhausting from the back of the HTPC compartment in the stand, and the other sitting on top of the PSU blowing through it.

I might do some gaming on it in the future as well, just to keep me busy without spending any money on home projects or other things I don't need to do right now. My wireless HTPC keyboard isn't very good though for gaming - it often misses keypresses and it has an integrated mouse that is lousy. It gets a little interference from my WIFI, it misses key presses more often when I'm downloading something large, so I'll have to figure something out in that department - works fine for watching shows, but it won't cut the mustard for gaming. The keyboard doesn't say what frequency it works at, but I'm sure it must be a similar 2.4GHz signal like the wifi... Changing wireless channels might have helped a little, but its still not great for responsiveness.

 

[hokiealumnus]

Steiger Dynamics (LEET HTPCs) said they researched what the best wireless accessories were that could stand up to gaming and they suggest the Logitech G700s mouse & Logitech K800 keyboard (refurb K800 for $35 off).

 

[I.M.O.G.]

Thanks Hokie, those look like good options to me!

 

[Operant]

I'll vouch for the G700 (haven't used the G700s). It is excellent for gaming, though be warned, it is a larger mouse. It has been designed more for MMOs or macro heavy gaming as opposed to FPS's. I still can get 1st in BF3 matches, though there was a bit of a learning curve coming from a super light oem dell mouse.

 

[NiHaoMike]

I went with the 5V mod from that thread and it quieted them down a lot. I also compared with 7V but both 5V and 7V on these fans show the same motor noise and 5V had less fan noise so I went with that. The motor noise is more of a pulsing click though low pitched, and isn't nearly as much of an issue as the whooshing air movement at 12V.

They're square wave drive fans, hence the ticking noise. Only way to truly fix that is to buy sine wave drive fans, but you might be able to greatly reduce the noise with rubber washers and soundproofing.