The first thing that annoys me is a noisy computer. The second thing that annoys me is a computer that heats a warm room up to unbearable temperatures. Not all of us have air-conditioned homes, so in the summer when it's 80 F outside, it's probably 90-100 F indoors by the fast 1.0+ gHz computer that...

Here's my Quick Start for playing with Quartz for this sort of fan noise exploration. 1. Install program. 2. Save a copy of that clicking wave file. 3. Open Quartz. When it asks what to do, click Continue . 4. In Tracks window at the top of the screen, click on the black button Audio 01 along the le...

Well, using just your posted sample and Quartz audiomaster freeware, your fan is not clicking but WUFFING . Played back at ultra-low speed, it is making a WUFF - WUFF - WUFF sound, once per revolution. I counted about 35 wuffs per second (counting wuffs at low speed playback), which times 60 gives m...

The other possibility is the sound of the electromagnets in the hub turning on and off, as discussed here near the end of the page. However, since the fan is such a compact unit, there's no easy way to tell if the sound is coming from the electromagnets or a rubbing hub/washer About the only way I c...

If you a trying for extreme quiet, you will notice new sounds that you didn't hear before with loud fans. From listening to your recordings, the noise sounds gentle enough to be a light rubbing of the retaining washer on the back of the fan hub, or the hub itself rubbing on the fan frame. First, let...

Just for the fun of it, I connected an old 80mm fan to a Radio Shack adjustable power supply, which allows you to choose voltages from 1.5v to 12v. The thing still spins up fairly well with plenty of torque to get spinning even on three volts, but does not move at all at 1.5v. The interesting questi...

Yes, that's why I'm mentioning a neutralizing grid. I don't have a digital camera handy, or I'd post a photograph of a device used in copiers to eliminate the ions and ozone from high voltage charges used in the printing process. It's a very large brick of activated carbon, with hundreds of tiny tub...

I'm just about to set up some case fans and I was wondering about pressure. I know that one advantage of having positive pressure inside your case is because it keeps dust out. As far as dust is concerned, positive or negative pressure will make absolutely no difference if you do nothing else to co...

If it's a sleeve bearing, then yes, trying to clean it is a waste of time. I posted this over there, but hey, might as well put a copy here as well. :) Oil and sleeve bearings absolutely do not work well together. I found this out the hard way years ago with a vacuum cleaner motor that had sleeve be...

Yes, indeed. If you are really serious about testing and measurement, tools are available to help you find out the details you are looking for. I just read a post from someone who wants to know the actual CFM of a fan setup. Measurement of that is indeed possible, using a device known as an anemomet...

What is tachometer simulation? A simulated tachometer output is a fake signal generated by a smart fan controller, for motherboards which think very low fan speeds indicate a problem. The controller outputs a signal to the motherboard's 3-pin fan connector that looks like a 5000 RPM fan, even if th...

Starting Torque, Under-Volting, Fan Wear, and Stall Issues What is starting torque? Most electric motors require more power to start spinning than they do to keep spinning. This resistance to movement is caused by friction in the motor bearings, the magnetic forces in the hub, the inertia of the hu...

I took some measurements of a fan I wanted to slow down and found that current was not linear with supplied voltage. The equivalent resistance, using Ohm's law, varied from 40 Ohms at 12V to 30 Ohms at 7V to less than 30 at 4V. So don't expect exact results the first try. This is because higher vol...

Undervolting can be a safety issue with larger devices. As the voltage drops, the device needs to draw more current to get the same power output. However, the wire size inside the motor limits this current, and so the device creates waste heat trying to pull all that power through small wires that w...