bcgardner wrote:

Paul,

You wrote: "You will have to stop the fan blades from spinning when the
power is off to the fan motor."

While I can see that this would be a good idea in order to reduce wear on
the bearings, are there any other reasons for doing so?

No but it will really zing at 200 MPH due to dynamic pressure
being 104 pounds per square foot as opposed to only 26 pounds
per square foot at 100 MPH.

Additionally, can you explain to me how the electric stop mechanism on an
electric lawn mower works? I have an electric mower and it kills the blade
as soon as the power is cut. Could such a circuit be easily and cheaply
adapted to an after-market electric cooling fan?

Barry Gardner
Wheaton, IL

You got me there. If you short a brush type DC motor that is rotating 
I think it retards the rotation. Some new DC motors are brush less and
all bets are off on those.

Paul Lamar

 
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