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On Wed, 23 Nov 2005 14:44:22 GMT, (~Roy) wrote:

It has to do with rotation of a motor....
Motor is a simple aquarium pump, submerged type, powered by AC current
of 115 VAC........2 wire power cord. Armature is the typical magnetic
type. Seems folks are dreaming that they can reverse rotation by
reversing the plug in the recepticle.......SOme have even gone to the
extremes of filing down the wide blade on the polarized plugs so they
can put plug in either way and think they are reversing
direction......Is it possible to change rotation of a AC motor like
this or not? If not, how about an explanatin why, and if it is doable,
an explanation as to how would also be appreciated........No other
mods to motor, just simply reversing plug orientation to reverse motor
rotation.....Not any need to get into the fact that the pump probbaly
would not work or work properly with a wrong rotation due to volute
design etc........

Won't work - it's a shaded pole fractional horsepower motor, and AC
is not polarity sensitive that way. Your submersible pump has the
core laminations and 120V winding coil all sealed inside it's outer
casing, so there is no way to get inside and flip the core and coil
over.

The only way to reverse rotation of an open shaded-pole motor (just
like the ones used in bathroom 'fart fans' and cheap range hoods) is
to take it apart and reassemble the rotor and bearings so the shaft
faces the other side of the motor, that way the copper wire pole shade
is on the opposite side of the motor.

It's usually simpler to get the right motor, or a reverse rotation
fan blade. Because the motor makers often do dumb things like make
the screw holes asymmetric. Or they thread the bearing holder on one
side to accept the through screws that are also the motor mounting
screws, and you have to start reaming out threads, cutting down bosses
to make clearance for the nuts, shim washers... (BT, DT.)

And that simple core flip won't work if there's any sort of one-way
dog clutch hidden in the rotor shaft bearings to prevent the motor
starting in reverse. You would need to reverse the bearings, too.

-- Bruce --

--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
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