Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!sharkey!mcf!teemc!mibte!jbh
From: jbh@mibte.UUCP (James Harvey)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Need advice on hardware projects
Summary: slow fan
Message-ID: <2793@mibte.UUCP>
Date: 24 Apr 89 17:21:52 GMT
References: <9891@netnews.upenn.edu> <6622@cbmvax.UUCP> <7916@killer.Dallas.TX.US> <17547@cup.portal.com>
Distribution: usa
Organization: Michigan Bell Telephone Company
Lines: 38

In article <17547@cup.portal.com>, FelineGrace@cup.portal.com (Dana B Bourgeois) writes:
> Eric Lee Green makes the comment that he doesn't understand why people
> want QUIET fans.  I *love* the A1000 fan because it is so quiet.  I can
> hear the telephone ring while it is on, I can listen to music without
> blowing down the doors, I can...well, you get the idea.
> 
> As for the quietness of a fan, I think there are two ways to reduce
> fan noise and both of them involve reducing the speed of the blade.  One
> way is to use an AC fan which is derated to reduce its noise.  This is
> a fan that may move say 55CFM that the manufacturer has slowed down to
> deliver only 30CFM.  The other way is to buy a DC fan which can be
> controlled by its input voltage.  In other words, get your hands on a
> 4 inch DC fan and dial the voltage up until the fan noise is just below
> what you consider 'too loud'.  I've seen a few DC fans in the surplus
> places and in the catalogs they are about 30-50% more than AC models.
> 
> Hope this helps.
> 
> Dana
If you can find one, a Two Microfarad, 200 volt, NON-POLAR (this
means paper, mylar etc. not electrolytic) capacitor in series
with the line slows down a 115 volt AC muffin fan just perfectly.

I did this for years on my Commodore 64 disk drives and I use
similar arrangements to force circulate air through the steam
radiators in my living room.  The advantage of using a capacitor
for dropping the fan voltage is that the capacitor doesn't get
hot like a resistor would.

-- 

Jim Harvey                        |      "Ask not for whom the bell
Michigan Bell Telephone           |      tolls and you will only pay
29777 Telegraph                   |      Station-to-Station rates."
Southfield, Mich. 48034           | 

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