On Tue, 08 Dec 2009 22:06:17 -0600, Don Foreman
wrote:




"Karl Townsend" wrote in message
ctanews.com...


You described the exact issue. Mechanically, I've got it geared down to
raise/lower 12"/minute with a total travel of 60 inches. Gets hard to gear
it much slower. My "plan A" is two stats so you have a dead band, then
play with % run to get response without oscillation. I suppose if you knew
exactly what percent on/off was optimum you could just gear it for 100%
on.

You can't know that because it will change significantly with cloud
cover, sun angle, wind, etc.




It ain't hard, it just ain't cheap. I used a double reduction
Sumitomo cycloid drive of 3400:1 to drive the continuous filter I
invented. Web movement maximum was 60"/hour, min was close to zero.
I'd mark the web, go have a cup of coffee, come back and stick a ruler
on it to make sure it was working.

Pete Keillor