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Old 15-05-2016, 07:01 PM
GC - South Aus's Avatar
GC - South Aus
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GC - South Aus is offline
Join Date: Apr 2008
Posts: 173
Modding my Schaefer AT Mount with a Losmandy DDS 492 *Help Needed*

G'day all, from South Australia.

I was perusing the forums/internet looking for an answer to my modification challenge of a Schaefer AT EQ Mount. Here is the link for my post on my mount:

This mount has had the 115vac 60hz Synchro Motors removed sometime ago. It now has two different stepper motors on it. The mount still has a tangent arm as I haven't got around to modifying the Dec Axis to a gear and worm (and probably won't for sometime).

Basically the setup is a 9" or 10" (not exactly sure) 359 tooth Byers gear. It's the Porter type mount, which means there is a bit of friction to overcome as the clutch is always engaged. There is a 2:1 reduction gear between the motor and worm on the RA. It currently uses the Bartels electronics, and a switch-mode PC for the steppers and electronics. The stepper on the RA is a 200 step TEC (3v 350 ohm). It also now has Argo Navis with encoders installed.

I don't have a permanent obs and to set everything up is a bit of a chore due to needing to not only setup the mount, but also the switch-mode PC and laptop to run everything. So I wanted to look at an alternative to that (especially when in the field), that is where the Losmandy DDS 492 comes in.

I am not too familiar or understanding of the ratios for the gear control, I am also concerned of burning out my stepper motors as using the Bartels software via PC it states the laptop must be on first and running before switching on the power to the motors. Otherwise it states you can damage/burnout the motors.

So my big questions are - Am I able to just plug my existing stepper motors in the Losmandy DDS board? Will this system potentially burnout or damage my motors? Will it keep the correct tracking rate? Or will have have to modify the gear train/electronics/speed?

Any assistance you are able to give would be greatly appreciated.



Last edited by GC - South Aus; 15-05-2016 at 07:29 PM.
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