Need sources for pot with planetary drive
The ratio, is determined by the shaft diameter, to the internal diameter
of the casing in which the balls sit.
If (for instance), you have a 3mm shaft, and 10mm balls, the casing has to
have an internal diameter of 26mm, and the ratio is 26/3 = 8.66:1. The
drive can be made remarkably good (the same system is used on some micro
focussers for telescopes, which carry significantly more torque than
needed for a pot). Units like the 'Williams optics feathertouch focusser',
use exactly this drive.
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Sorry ,but I don't understand the above .
If the shaft has a diameter of 3mm and the balls a diameter of 10mm, the
inner diameter of the casing should be 10 + 10 + 3 equals 23 mm
When the shaft makes 1 revolution the balls will make 3/10 revolution .
When the balls make 1 revolution the casing makes 10/23 revolution .
Hence when the shaft makes 1 revolution the casing will make
3/10 * 10/23 equals 3/23 equals 0.13 revolution , hence reduction factor
is 7.7
Please correct me if I made an error.
Frank GM0CSZ / KN6WH
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