[rescue] fans came today.. I ask again: dual fans?

[Bill Bradford]

On Mon, Jul 01, 2002 at 02:27:13PM -0500, Leslie Connally wrote:
> so: fans came today for the U1.. and I ask again: should I install dual
> fans? Any reason 'why not' ?
> current draw?
> overspin of lower fan???
> static build up of moving air ????????

They're not big enough to cause a problem, but you NEVER want to install
two identical fans on top of one another..

If they start rotating exactly in sync, they can setup a harmonic vibration...

(I heard that some wind tunnel facilities would have two fans - but not with
 the same number of blades, for that reason...)

Bill

-- 
Bill Bradford     
mrbill at mrbill.net 
Austin, TX