Re: Question on Torque, Currents, steppers, voltages, CONFIG settings


Prasad
 

Ken

Guy is 100% on the mark. I was there when Guy removed all the balancing weights on the RA axis. The DEC axis has no load at all. In this condition, I have tried to turn the worm that drives the RA axis by hand. It was very free in both directions (remember 1:359 ratio) but it did get a bit tight at certain positions. This was due to mechanical binding between the worm and worm wheel. Then we loosened the fasteners that hold the worm shaft and the movement became really free in both directions when turned by hand.  (But created some backlash which did not matter for testing the motor). It was very cold that day and we were late. So we wrapped up without completing the adjustment. 

So, as long as the worm shaft is loose in its engagement with its mating worm wheel (gear) it should be OK. The penny is all that is needed at the moment. Of course, adding a good cold temp lube would help additionally, maybe half a penny would work. Guy has made progress since then because he has coupled the second stage worm shaft in its place during his recent visit.

Guy, I hope I am right in my understanding/interpretation. Please correct as necessary. Thanks

-Prasad 



On Friday, January 14, 2022, 11:20:01 AM EST, Guy Brandenburg via groups.io <gfbrandenburg@...> wrote:


Hi, Ken,

Right now, we have taken absolutely everything off of the mount, except for some bolts: all four OTAs, all of the finders, all of the counterweights, the large steel plate all of that was bolted to, and even the cover for the Ealing counterweight box.

When the mount was last operational, we balanced everything on both axes and in all positions by adding or subtracting counterweights of various sizes and compositions, in various locations, and also by sliding some of them along special grooved racks we fabricated. And loosening and sliding and reclamping the OTAs as needed. If we attached any imaging gear, we re-balanced. (Or at least I did. I hope other users did so as well.)

Right now, during very preliminary trials, it’s not balanced at all in RA because the empty CW box sits on one side. The DEC axis is balanced because the six remaining bolts are evenly spaced. My next stop will be to fabricate and rig up an counterweight of some sort to balance out the empty Ealing counterweight box.  Maybe this weekend. I wish it were not 50 miles away.

In raising a big weight with a penny, it’s like Archimedes supposedly said: all you need is a long enough (weightless) lever, or (I would add) the proper gear set, and almost no friction….

, which capitalizes Weirdly & misinterprets words just To keep you on your toes





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