On 23 Nov 2005 14:33:13 -0800, jim rozen
wrote:

In article , Bruce L. Bergman
says...

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.

Well there is one other way. You cut the shading ring so it's no
longer continous. Then the motor can be started by hand in either
direction.

We had a dishwasher where the timer motor had this defect. It would
run in either direction, at random, when started. Sometimes I would
have to 'start' the dishwasher several times before it would head out
in the correct direction.

It was also ill-advised to stop the machine in mid-cycle, and restart
it. The standard joke was that it would run backwards and make them
dirty again.

The shading pole piece probably fractured at a bend or weld, which
would cause that propensity to start in either direction. The one-way
dog clutches that they use especially on timer motors are supposed to
prevent the motor from starting in reverse, but they wear out 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
Spamtrapped address: Remove the python and the invalid, and use a net.