Direction of Electrical Motor Rotation

[watson]

G'day All,
I have bought a few of the MAC 2 Microwave Platter Motors from Oatley Electronics.
As per here:
http://secure.oatleyelectronics.com/...roducts_id=646

I intend to use them to power some wooden automata I've been playing with.
However, upon switch-on the motor will go clock-wise or anti-clockwise - probably an even money bet which way it will go.
Any thoughts on making it go in the one direction every time???

Thanks in anticipation,

[Brickie]

You have to count as you switch it on, if it goes one way and you want it to go tother way add 1 when you count.

[petersemple]

From what I could work out you have a synchronous motor. I think that reversible synchronous motors require a capacitor to determine direction. I'm not sure how you work out the size of capacitor. Maybe the manufacturer has a data sheet available.

Peter

[DavidG]

That type of motor is a 50/50 bet as to which way they will start. No capacitor or start windings.
You could use a spring loaded ratchet that throws the direction the other way if incorrect, but very messy to build.

Better to buy some proper motors.

[watson]

Thanks All,
Food for thought.......I just couldn't resist 5 RPM motors..to save on gearing. Cheap Bugger!
I've got some mains rated capacitors that I could play with just in case, and I thought Brickie was off the mark, as I thought sticking my tongue out either side of might influence direction

[malb]

Generally these suckers do exactly that when in service in the MW oven, so I don't hold a lot of hope for their being an easy fix. The purpose being to try and ensure an even exposure to radiation, it doesn't matter a hoot whether they rotate successive batches in the same direction.

Non geared motor might be good for the automata, but these things are then going to need mains power to run. Technically, the motor and mains connection would require the complete unit to be approved by an Australian authority if you intended selling it. Approval used to start at about $5,000 20 years ago.

Some other system might be more predictable and economic in the long run.

[watson]

Thanks Malb,
Good info, but these devices are for my own enjoyment...and to keep me off the streets.......so I wouldn't be selling any of them.
I just had a quick play with our newest microwave, and it runs the same ...so I guess I'll just build things that don't depend upon directional rotation......( I hope)