Re: turntable

> Ross thanks for the info on the encoder, I was thinking about not hooking up
> the encoder, and using 2magnetic switchs (so i can tell if this table is at
> home or 180 degree).. do I really even need the brake?
>

No, you don't need the brake. Are you just trying to turn a part 180 degrees or do
you need a syncronous 4th axis. If all you need to do is manually index a part at 180
degrees, a manual table with locking detents at 180 degrees might be a whole lot
easier and cheaper.

These motors were used on satelite dishes back when a dish was 8' in diameter. The
brake was used for exact positioning. The globe motor that drives the table is a gear
head motor. When you remove power from the motor, it does not stop dead. It takes
about a second to spool down. This would probably not be an issue if you used an
encoder with a servo drive.

How will you drive the motor? To control it via software, you'll have to drive it with a
servo drive and encoder. You might find more info here...

http://www.rainnea.com/cnc.htm

Rab has used these to make articulating spindles with some success.

Ross