Posted 13 October 2013 - 09:56 AM
Posted 13 October 2013 - 10:27 AM
Larger, slower fans are quieter than faster ones. Keep the speed below 1500 rpm. If dimensions allow a 120 mm very slow fan is nice. Not knowing the size of your scope it is hard to recommend something particular, but check this out for advice on CFM ratings:
The best bearings are hydrodynamic or magnetic bearings, they are vibration-free and will never wear out. There are a bunch of different names manufacturers use for these suspension technologies - it is perhaps easier to avoid ones with the descriptions of "ball", "sleeve", "rifle", or "oil" (though look for bearings containing "hydro", "magnetic", "barometric", "flux", or "fluid" in their descriptions).
Additional vibration protection can be had by using an elastomeric mount - suspending with rubber bands is popular, but gluing the fan on to small blocks of foam is very good and may be easier.
A good place to shop for fans, with a vast selection, good prices, and an excellent search system is NewEgg:
(A bizarre "feature" of many fans is having an LED, it seems that many nerds/geeks are attracted to the bright flickering light - either avoid these or plan on removing it.)
Posted 14 October 2013 - 02:14 PM
I've chosen the Noiseblocker UltraSilentFan-XL2 (120mm) for a 16". I'm sure 80mm would have been OK as well.
Posted 25 November 2013 - 10:11 PM
Posted 26 November 2013 - 06:12 PM
Posted 27 November 2013 - 01:16 PM
Posted 27 November 2013 - 02:27 PM
You might be disappointed by that fan. It only flows the same amount as the stock 80mm fan. I originally got a similar one only looking for the quietest fan with no regard to the amount of airflow. Yes it was vibration free but even mounted in a baffle it seemed to take forever to cool my 10" dob. After learning that $20 lesson I purchased a fan with a great combo of flow vs noise. http://www.newegg.co...N82E16835103061
Here's what I ended up getting.
I'll let you know how it works when I get it mounted and try it out but it will be a while until then.
It's rated at 69cfm and 19db. I got the one with red LEDs thinking it was behind the mirror it would be ok. Wrong, I had to clip the wires to the LEDs.
Now at 12v my mirror is cooled in about 20min with a baffle and Deleo ring to direct the airflow around the mirror. I bought an AC adapter with selectable voltage and the fan will run on 6/9/12 volts. When observing I usually run it at 9v. Good luck.
Posted 08 December 2013 - 08:03 PM
I see fans listed as PWM. What does that mean and can I use one.
Posted 08 December 2013 - 09:29 PM
Thanks for the info on the PWM. I take that we don't have any way to control one? Or do they take a controller?