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Dec. 6th, 2005

If I wanted to make some gadgets to slowly rotate a platform at a fixed or variable speed, with really only minimal torque (just spinning about 75g total mass at most) or nutate or orbitally shake, what kind of motor would I want to use there?  And where could I get some (between 5-25 maybe) for cheap?  Could I run them right out of 110V or would I have to put a big funky transformer in front of them?  I'm getting of using broken or worn-out stuff or paying 500-1200 for something that I know must be 100 bucks in parts.



( 4 comments — Leave a comment )
Dec. 6th, 2005 05:38 pm (UTC)
How fast do you want to rotate? You can buy record turntables and spin at 33rpm fairly cheaply. Put a diode on the AC sync. motor and slow it down 1/2. You could even buy a cheap fan and rotate a much larger round table very slowly by putting a small rubber wheel on the motor shaft and use that to run the circumfurance of the stage (which is how a giant stage work anyways.)
Dec. 6th, 2005 07:48 pm (UTC)
I was thinking between one and 10 rotations per 10 seconds maybe, variable if possible. I'm trying to recreate a few different tools, like platform shakers and microfuge tube rotators, so the size of the platform would be either ~12x16" or a liter bottle-sized tube holder. I never thought about using a simple oscillating desk fan; it's cheap although way too fast. Is there a good way to slow down one of those fan motors without messing up the lifespan or heat output?
Dec. 6th, 2005 11:00 pm (UTC)
It may be possible to put the fan after a high-capacity dimmer circuit. I don't know, I've never tried it. You can always slow the rotation down by having the table be X diameter and have the motor shaft drive a wheel of Y diameter that's contacting the outer circumfurance of the table, which would make the table turn at Y/X speed.

Example: Table is 3.14feet circumfurance (1foot diameter table). Motor shaft drives a 3.14inch circumfurance (1 inch diameter) rubber wheel at 1200rpm (20rps). For every rotation of the shaft, 1/12 rotation of the table will occur and you'll have a speed of 1.67 rps on the table.
Dec. 6th, 2005 11:44 pm (UTC)
I'll let you know of what you are looking for later tonite. I just gotta remember where I got it.
( 4 comments — Leave a comment )