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=?iso-8859-15?Q?Tekkie=AE?=

posted for all of us...

On Thu, 26 Jul 2018 17:15:06 -0700 (PDT), trader_4
wrote:

On Thursday, July 26, 2018 at 7:57:46 PM UTC-4, wrote:
On Thu, 26 Jul 2018 15:48:42 -0400, Tekkie®
wrote:

What is the difference between A/C (air conditioning) fan motors that use a
start capacitor and say a ceiling fan that doesn't. Type slow because I'm
not too bright and getting worse...

We finally get to say "split phase" and be correct. The capacitor
actually does "split" the single phase in conjunction with the start
winding in the motor and it creates a temporary "2 phase" system for a
second until the motor gets out of locked rotor.

Smaller motors may be "shaded pole" that create a magnetic shift in
the motor windings themselves without a capacitor. Usually, if you
look you will see a much larger gauge winding there, maybe only one or
2 turns. That creates the shaded pole.
They are not particularly efficient and they have very low starting
torque but if it is a $12 fan from Walmart, what do you expect?
The other place you see shaded pole motors is in small gear head
motors like you might see on a refrigerator defrost timer. Since the
gear reduction is so great and the load so low, they don't need much
torque.

The question remains which of those is in most ceiling fans and does
it use a cap? Looks to me like most are split-phase, in which case
they use a cap and are in the same category as the AC motor.

A ceiling fan is usually a split phase motor with a start capacitor
but it is not a very big capacitor since they don't need a lot of
torque. The cheapest ones might even have a shaded pole motor and a
top of the line model may have a brushless DC motor.

I never knew they had capacitors in them. Of course I didn't do a through
exam of any on a ladder or destruction. I always assumed they were shaded
pole motors.

Leads to the next question: How do they perform different speeds?

--
Tekkie