Date:         Wed, 5 Aug 2009 15:38:40 -0400
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: Dometic Rear Fan *prop* Better than CPU Fan?
Comments: To: neil N <musomuso@GMAIL.COM>
In-Reply-To:  <c4e7c5f90908041433r70915591p114fd3ec77031067@mail.gmail.co m>
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At 05:33 PM 8/4/2009, neil N wrote:
>Has anyone else found that the Dometic blade is a better design than a
>muffin fan?

Muffin (R) and similar box-type fans are designed to be thin so as to
mount easily into equipment chassis and such.  As such they have
coplanar motors and in the smaller sizes (less than 8-inch, say)
there isn't much room for the fan blades.  As such they run fast and
noisy for a given output.  The Dometic fan OTOH was designed to run
slow and quiet (rated input power is 0.7 watts, BTW, about 60 ma --
so at 270 ma yours obviously has problems or is in fact not an
original) without regard to size.

>And could anyone tell my why the cassette tape motor fan spins faster
>when polarity reversed?

Cassette drive motors have a speed regulator on them.  The old ones
were centrifugal but I suspect yours is electronic and won't work on
reverse polarity.


  --
David Beierl - Providence RI USA -- http://pws.prserv.net/synergy/Vanagon/
'89 Po' White Star "Scamp"