EAF loose movement on motor shaft

Focusers, Filters, Barlows etc..

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Joined: Tue Oct 15, 2019 8:37 am

EAF loose movement on motor shaft

Post by Barns » Wed Oct 16, 2019 8:35 am

Hi, I recently bought and fitted an EAF to my Skywatcher Esprit 100. I have an issue that there is significant backlash present in the system, which I have isolated back to the EAF unit itself. When fitted, I would expect the scope focuser to be held rigid by the EAF, however there is a fair amount of movement back and forward possible if I gently turn the manual focus knobs on the scope. I can see that this is rotating the motor shaft of the EAF back and forth as well by some degrees. The backlash is not in the scope focuser (the focus tube moves smoothly back and forward as I turn the focus knob). It leads to a backlash movement of about 1.5mm on the focus tube, which is plenty large enough to make a mess of focus routines.

It indicates to me that the motor / spindle assembing inside the EAF has some "play" in that the motor starts to try turning the spindle, but first a backlash amount needs taking up before the spindle begins to rotate.

I am aware that it's possible to set backlash values in the drivers and also in other software, and have done so, but my EAF seems to need very large backlash values setting and even then it struggles to get reproducable movements.

So what I'd like to know is what degree of movement is to be expected inside the EAF? Should the motor shaft be possible to easily turn manually in this way, leading to large backlash values? Or do I need to send this EAF unit back to my dealer for replacement?

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Joined: Fri Dec 07, 2018 10:24 am

Re: EAF loose movement on motor shaft

Post by Support1@ZWO » Thu Oct 17, 2019 6:31 am

Hi Sir,
You can set larger backlash in the software, the steps in different focuser is different.
EAF cannot be turned manually, it must be controlled by software or hand controller.

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