Art Todesco wrote:
Well, if it always turns in one direction the food will tangle, so you must
untangle ..... just kidding. Many gear-head motors that run on 110 AC,
have "shading rings" to set up the magnetic field so they always rotate
in the
same direction. These are 1 turn chunks of copper that will go through
and/or
around the steel laminations. I have noticed in the last few years,
many small
motors like that, don't have shading rings and will start in a random
direction.

What kind of motors do you think those are?

AFAIK, without shading rings a simple induction motor will not self
start. But, there are all sorts of small motor designs around now I
never encountered when I was a kid, just think about what's in a modern
automobile.

Perhaps they're using DC motors, two phase AC motors, or some kind of
stepper motor for those microwave turntables now, driven by a few
components on the appliance's circuit board.

Based on what Edwin said, I doubt that the starting direction is really
"random".

Jeff

I guess if it doesn't make any difference, like in a microwave
turntable, it makes
the motor $0.00001 cheaper. BTW, my microwave does the same thing.


I know my 4 year old GE microwave's turntable always rotates in the same
direction as my grandma's Victrola's, but it might be interesting for
the OP to run some tests or even, G-d forbid, RTFM and let us know if
it's really random.

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.98*10^14 fathoms per fortnight.