On Jul 13, 8:02 am, "HapticZ" wrote:
i remember these used to have slippage problems at the ball to shaft (after
a few hundred rotations) and required feedback looped mechanical drives to
accurately position anything they were used to control.

try something new!

"msg" wrote in message

...

Greetings:

Please view these photos of a three-turn planetary drive
pot that uses a conventional "stackpot" formfactor at
http://www.cybertheque.org/homebrew/...tennas/pot.jpg
Resistance = 1K

It was made in 1966 by CTS; stampings: 36129 137.6637

Does anyone recognize this pot technology? Any suppliers
nowadays? I need the form factor for modifications to antenna
rotator assemblies in a space that does not permit using
larger multi-turn pots and using trimmer versions is not
sufficiently robust.

Regards,

Michael
msg _at_ cybertheque _dot_ org

I remember them, also, and the slippage. I used to lube them to make
them work better. They didn't.

I now know they must never be lubed and must be kept really clean.
They work because of the friction between the shaft, the ball and the
housing. Our pick-and place machine, used to place SMT components on
circuit boards, uses the same technology to convert rotary motion to
very accurate linear motion. The wheels and shaft must be kept very
clean, or we get positioning errors.

I have no clue about the current source of the devices, but probably
have a few in the junk box!

Paul, KD7HB