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 turntable/220 controller dilemma.
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Posted - 2010 December 14 :  11:49:01 AM  Show Profile
I'm a novice builder building my first layout, and I have a question regarding the use of a 220 controller to control my turntable.
I have the "updated for 2008" version of the complete atlas wiring book (#12) and I found a rather confusing example of the use of a 220's XY direction switch output to control my atlas motorized turntable. Instinctively I assumed I would use either a fixed 12VDC output, or an AC output with a rectifier to drive the turntable motor.

first which could be adding to my confusion is a possible typo. On page 16 in all figures they show DC (I assume variable loco) connectors on the right end of the power packs. however in figure 2-12 on page 17, they show the output labels swapped as well as the connections. Now that I look through the entire book, the output type locations vary throughout the entire book. (not very good editing in my opinion)

As I understand it, current comes in on the left end of the controller, and it flows across to the right end to the selectors. Doesnt that mean if you are using the controller as shown to control, the turntable motor, you are actually using the variable DC loco output to drive the turntable, making it more difficult to operate it? (e.g. you must remember to switch off the turntable rails before turning the power to the loco back on so that the table moves and the loco doesnt)

Or am I missing the point?

Country: USA | Posts: 2

Roger Perkins

Posted - 2010 December 14 :  5:46:21 PM  Show Profile  Visit Roger Perkins's Homepage
There is a commercially available indexed turntable which comes in DC and DCC versions.
It is very enjoyable to use and a nice challenge to install and get tracks aligned and indexed. Solves the wiring and power lead questions.

Country: USA | Posts: 3351 Go to Top of Page

Charlie Vlk

Posted - 2010 December 14 :  6:11:58 PM  Show Profile
If I understand the problem correctly, the turntable motor needs to be on a reversable DC output so you can change the direction of rotation (clockwise, counterclockwise).

Power packs vary in the location of the terminals. You might want to use a separate pack so you can control speed as well as direction of the table.

I don't know how the polarity of the track on the turntable is handled on the Atlas unit; that is an entirely different problem (it may be built into the design of the TT). Does anyone have the instruction sheet for the Atlas N Turntable that they can scan and send to cameramonkey?

Charlie Vlk

Country: USA | Posts: 1704 Go to Top of Page


Posted - 2010 December 14 :  6:12:12 PM  Show Profile
Actually, on my turntable, I used the regular handheld throttle. Since the loco can't be moved while it's on the turntable, all I need is a simple DPDT switch. Run the loco on to the table, flip the switch to "turntable", use the throttle to run the table, switch back to "train", run the loco onto the exit track.

Now, this wouldn't work with DCC, as the loco and table motors would have different addresses. But for DC, without indexing, it works fine, and is about as cheap and simple as one can get. The table track wires HAVE to go to the table, the table motor wires are right there, so run them both to the same toggle switch. It will also work with multiple cabs, as the track power comes from the block selector switch.

N. Kalanaga
Be well.

Country: USA | Posts: 4452 Go to Top of Page


Posted - 2010 December 14 :  6:32:57 PM  Show Profile
There are all kinds of options for running a TT
1 - fixed DC voltage (9-12 volt wall wort) and a DPDT switch
2 - run it as a seporate block using an Atlas contorler?/selector and a DC power pack
3 - run it using DCC (over kill in my opinion since option 1 is the cheepest and it can be controlled locally)

I'll try to draw how I've done it in the past, and post tomorrow.

Do your part buy stuff!

Country: USA | Posts: 2536 Go to Top of Page


Posted - 2010 December 14 :  9:37:35 PM  Show Profile
Thanks guys.

I have two copies of the instructions for the atlas TT, so that isnt a problem. I can quite easily hook it up using one of my older ControlMaster II units (or a wall wart) and a separate DPDT, but was looking to simplify my control panel since I already had what Atlas claims I need to run it (and wasnt going to have any wyes, etc so it would be unused otherwise). I wanted to make sure what I was seeing in that manual was really what they were describing, and not a weird typo since they swapped the outputs on the drawings, muddying the waters.

The actions that Nkalanga use is how I interpreted it, but wasnt sure if thats what they meant since using fixed DC seemed more straightforward to me(at least in my mind).

The very basic Atlas TT I have is an indexed turntable in the most basic sense. as the motor spins, it reaches the centerpoint of a feeder rail and a gap in the gearing system (missing teeth?) causes it to halt for several rotations of the motor (about 2-3 seconds when driven by 12VDC), allowing you to stop easily without the "oops, too far" problem. Its far from sophisticated, but quite effective.

while I would LOVE LOVE LOVE the new Atlas Cornerstone series well-type turntable as demonstrated in the new 2011 Walthers catalog, I dont have $350 burning a hole in my pocket (plus the cost of a DCC unit). the basic turntable will suffice I think. Maybe after a while when I get some experience (and more room) I'll tackle that one.

Djconway: dont worry about the diagram. I have a handle on it now.

Thanks to all. Glad I wasnt missing something.

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Posted - 2010 December 14 :  10:03:55 PM  Show Profile
If you're using the old-style turntable you can probably get by with a fixed DC supply and reversing switch. Mine is a motorized Peco, with no indexing, so variable speed control is essential to get it to stop in the right places.

N. Kalanaga
Be well.

Country: USA | Posts: 4452 Go to Top of Page


Posted - 2010 December 15 :  6:32:00 PM  Show Profile  Visit s40er's Homepage
Since the Atlas TT has indexing, all you really need on your control panel is a single DPDT switch with center off to control the turntable. Center would be off, and flipping the switch would control direction of turn or off.

You can use a fixed DC power supply or an old variable DC throttle ( set to your desired throttle setting for speed you want the table to turn) hidden under the layout to send the power to the switch in control panel.

It would be wired like the attached picture.

Yes it's true, I'm back, but I still have no idea where I went

Edited by - s40er on 2010 December 15 6:34:30 PM

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Posted - 2010 December 16 :  4:52:50 PM  Show Profile  Visit locomcf's Homepage
Originally posted by nkalanaga

... Mine is a motorized Peco, with no indexing ...

I also have a Peco turnout, and I'd be interested in seeing how you've motorised yours. What motor did you use, etc.?

Ron McF

Country: Australia | Posts: 327 Go to Top of Page


Posted - 2010 December 16 :  7:34:31 PM  Show Profile
I didn't. I bought it, years ago, already motorized. It came with a machined aluminum bracket, large DC motor, and gearing, ready to install. All I did was lay narrow gauge ties over the deck, then add walkways and rails. The original rails are still under there, but don't show, so it looks fine. Peco may sell a motorizing kit, but this was a third-party job, and probably hasn't been made in years. At twelve volts it takes almost a minute for a full revolution.

N. Kalanaga
Be well.

Country: USA | Posts: 4452 Go to Top of Page


Posted - 2010 December 16 :  7:40:25 PM  Show Profile
If I had to build my own, I would probably start with an aluminum angle or channel from the hardware store; a large DC motor, possibly from a discount electronics dealer, or maybe an HO/O loco motor; a NorthWest Short Line gearbox (or maybe two) for reduction, and a selection of NWSL shafts and gears. Usually the larger the motor the lower the RPMs, and you want the slowest motor you can find, to make the gear reduction easier to buy/build. As long as you have enough room under the layout, and mount the motor directly to the turntable pit, everything should stay aligned. Using a worm drive gear box will keep the table from turning when the power's off.

N. Kalanaga
Be well.

Country: USA | Posts: 4452 Go to Top of Page
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