[Barrykgerdes]

Hi Frank

Driving a DOB so it will track is quite a task.

Have you mounted it on an equatorial platform or is it on a true equatorial mount? The procedure can be quite different.

The first consideration will be the azimuth bearing that will become the RA axis. Because the platform will be tilted the bearing will need side thrust control as well as vertical and because the tension of a drive belt will need to be taken into account. I once modified a DOB mount with proper thrust bearings for for the azimuth but I have a well equipped machine shop.

The next consideration is the drive method. Here the use of toothed belts can be used. I salvage these from old printers etc. The overall gearing for the belt stage will need to be as high as you can get 360:1 is a good aiming point as normally achieved by a worm drive but may not be practical in you case. My old DOB drive used a primary reduction of 60:1 with a combination of a belt stage and mechanical gears (stolen from my Meccano set)

A stepper motor drive will probably be the easiest way to go but the overall reduction will need to be at least 360 x 60 x 60 to get a reasonably smooth drive. This will mean a microstep drive on your stepper.

Once you get to this stage the Bartel's system has all the electronics designed to drive your stepper.

The drive system that you already have I suspect is designed for the US 60Hz system and it will probably use a standard small shaded pole type motor. The speed of these can be controlled within limits with a variable frequency power supply. However this method is asynchronous not synchronous

If you have photography in mind this system will be virtually useless of course and for visual use an alti/azimuth drive will be much easier to implement even with a stepper drive for both axes. That is all I used for my old DOB mount.

Barry