On Nov 20, 2004, at 3:10 PM, Harold B. Mandel wrote:
Pat Stein at Commander Amplifiers readily admitted that the Dayton
shaded pole turntable-type blower motors run very hot in the Commander
amplifiers, like 180 to 200 degrees F.
Dayton motors are a big advantage on Antarctic DX-peditions.
One of the fresh air inlet grates is directly below the fan motor so
there is some
cool air going across the motor body.
I didn't find any lint or debris in the bronze bushings and there was
still floating around and the armature spun freely. I can't imagine
why the fan
refused to start other than in the new series of Commander amps the
is on the soft-start circuit AND has a 75 ohm resistor in series with
of the fan motor leads (that is shorted out for a fan speed increase in
Since the technical information about shaded pole motors does say they
hard to start, I wonder if the combination of series resistance and
soft-start circuitry sometimes prevented the motor from starting?
Hal -- My SB-220 fan's shaded-pole motor has a 75-ohm resistor in
series with it when the exhaust air-temp is cool. When the air gets
hot, the 75-ohm R is shorted by a thermostat to speed up the fan.
There has never been a problem with the motor not starting,
Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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