A question about stepper motors

[peteski]

You are definitely on the right path, Otto.
I picked up stepper motors and 3 turntable drivers from an Australian electronics supplier to make my life even simpler.   The combination works like a charm - slow & smooth!  Just need to figure out how to bash the peco pits to look wooden lined.....

Michel

But Otto went with a geared DC motor, not stepper.

[MDW]

Oh crap..... yep, should have read that more carefully.
In that case, the stepper motor is a suitable alternative to Otto’s fine solution.

Michel

[Cajonpassfan]

Lol, yes I did go with a DC motor for now, so the thread title is misleading.Trying to keep it simple (the old KISS method).

To keep the drift going, now I’m looking for a cheap basic auto-reverser for the bridge rails, maybe a Digitraxx AR1.
A question: if I wire the AR1 for the TT bridge as a subset of a power district that already has its own protection (PSX1) will the AR1 be quick enough to not trigger the district PSX1?
Advice appreciated,
Otto

[Cajonpassfan]

To wrap this up, for those interested, I got the turntable drive and electronics pretty much done, see below. No steppers here...
More on my ATSF Los Angeles Division thread.
Otto K.

[peteski]

Nice! I like the juxtaposition of wooden constructions and high-tech electronics.
So the bridge is driven by a DCC decoder?  What is the larger board for?  Bridge polarity?

[Cajonpassfan]

Yea @peteski, the larger gizmo is a Digitraxx AR-1 polarity reverser (even though as we know there is no such thing as polarity in DCC), and the smaller gizmo, loco decoder, powers the turntable motor. What I like about it is that both starting voltage and top speed can be programmed by a couple of CV’s and the direction of travel (clockwise/counterclockwise) is handled by the forward/reverse commands. And...I do not need a separate turntable panel, and...the turntable can be operated from both adjacent/flanking operator isles using a local DCC cab. More on my ATSF Los Angeles Division thread.
Thanks for your interest,
Otto

[peteski]

Very clever Otto. Old-school mechanism meets contemporary technology.  I like the idea of a DCC throttle controlling the turntable bridge (and the polarity takes care of itself).  Or to be technical, you can state that "phase matching takes care of itself", but nobody talks that way.   

[Cajonpassfan]

Thanks Pete. I programmed the NCE mech decoder tonite, with CV2=60 and CV5=120. That gives the table a nice slow start, and a top speed of about 3/4 RPM per minute. You can use the throttle to slow it down to “eyeball” the alignment. I may need to tweak it after the table is installed, to overcome weight and friction if any. So far, so good...😎
Otto