MWO platter motor direction control

[alah]

HI, ALL. I hope this post is not repeated, having problems with internet.
I want my motor to always start in the same direction; I tried with a capacitor without luck.
Is it possible? Thanks, Alberto.

[james_s]

What is an NWO platter?

If the direction is random without the wiring changing then that sounds like a synchronous motor. These typically use a mechanical ratchet-like mechanism to prevent starting in the wrong direction.

[mark03]

I assume MWO = microwave oven.  I always wondered why the platter in mine rotates in a random direction.

[james_s]

Ah, yes those use synchronous motors, at least the ones I've taken apart do. If there is nothing mechanical to prevent them from going one way or the other then the direction of rotation will be random depending on the position of the rotor when power is applied. If you stall one it will usually reverse which is how the little ratchet mechanism works.

[amyk]

I've seen mention of controllers for bidirectional single-phase synchronous motors of the type described here, which can always start them in a controlled direction by sensing the back EMF and adjusting the waveform appropriately.

[james_s]

It would be interesting to see a design for one of those, although I can't help but wonder what the motivation is in making the turntable always turn the same direction, beyond satisfying one's OCD tendencies. It would probably be easier to replace the motor with a different type.

[alah]

Im not using it for the platter; it turns a palanca which activates contacts as a mechanical relay. I managed to modify my arduino code to solve this problem, anyway. THANKS for answering.