Large Scale Central

DCC Turntable power

Electronics DCC
#1

I am about to start building the Turntable for my Indoor Fn3 Layout and I am using CVP Products Easy DCC system and what to know what the common practice for powering the turntable and changing the polarity to match the various track that radiate off it as it rotates around. my turntable will use a hand crank to rotate it. is it as simple as just wiring a DPDT center off switch wired like a reversing switch? I am not interested in making it overly complicated or adding electronic auto reversing modules.

Any help will be appreciated

Dan

#2

is it as simple as just wiring a DPDT center off switch wired like a reversing switch?

Well, yes, and it gave my brain a small workout to think about it.

I’m not a DCC expert but I believe you have constant DC voltage on the track (+signals.) Consider when a loco drives on to the turntable and turns completely around 180 degrees to leave the way it arrived. From a DCC perspective, it is still going forward. But the track is flipped and the DC on the turntable is now opposite the polarity of the entry rails. So you need to switch it with the DPDT reversing switch.

(Looking forward to hearing the experts opinion - whether I got that right!)

#3

https://dccwiki.com/Turntables

#4

And how do you address the track polarity of the storage tracks. This is where the DCC reversing sensor works well on the turn table track, or the truntable track needs to supply power to each storage track when selected/stopped.

#5

You have two situations…

A - Simply using the turntable as a movable bridge to enter the roundhouse going forward, or reverse if you backed on to the table.

B - Using the turrntable to turn the locomotive and/or enter the roundhouse in reverse.

Situation A only requires the roundhouse tracks into be wired the same as the approach and the table. Situation B requires a polarity swap, most simply done with a DPDT wired for polarity swap.

EDITED to correct error and to acknowledge that Pete’s thought of only switching the track on the table itself is the simplest. That allows both A or B to happen. For A you leave the switch alone, for B you swap polarity.

#6

Dan Pierce said:

And how do you address the track polarity of the storage tracks. This is where the DCC reversing sensor works well on the turn table track, or the truntable track needs to supply power to each storage track when selected/stopped.

My answer, if it was my railroad, would be to wire the storage tracks directly to the approach track(s). That way they are all at the same polarity. The only rail to switch polarity is the turntable when you rotate 180 degrees - and that’s easy to see when the loco is to move off the turntable in the opposite direction from the way it arrived.

I am not suggesting you can’t use a DPDT relay or some special DCC device. Just seems a bit too complicated to me.

#7

Pete: This is how I have been thinking about solving the wiring issue for the turntable. I know a lot of People are heavily into DCC and want everything automated and can control every aspect of their layout from their throttle using the function buttons. I am old school and have resister converting to DCC for a long time, but I do like that ability to have sound and run more than one train at the same time. I chose to go with CVP Products Easy DCC system as I liked it simplicity and frankly the price. As I model late 1800’s to early 1940’s on my layout I wont be running power sucking diesels and doing multi lash-ups so I dont need all those CV functions. I will only be using the CV’s that are associated with a basic steam engine and thats all. All of my Turnouts are either operated by hand operated brass switch stands or servos using a very simple control board that I make for about $4.00 each and these will be wired directly to the control panel.

So I am using an old school method of DCC power reversing for the Turntable. It is simple, not overly complicated and I am sure that it will work and be reliable in the long run.

not sure how to post pics here, so this is the link to my website and the page when I have the wiring diagram. http://www.danstrains.net/my_layout_dcc_wiring.html.

I am open to any suggestions and improvements as long as it does not involve expensive DCC automation and JMRI. My Layout will not be connected to a computer in any shape or form.

Dan

#8

Dan Stuettgen said:

Pete: This is how I have been thinking about solving the wiring issue for the turntable. I know a lot of People are heavily into DCC and want everything automated and can control every aspect of their layout from their throttle using the function buttons. I am old school and have resister converting to DCC for a long time, but I do like that ability to have sound and run more than one train at the same time. I chose to go with CVP Products Easy DCC system as I liked it simplicity and frankly the price. As I model late 1800’s to early 1940’s on my layout I wont be running power sucking diesels and doing multi lash-ups so I dont need all those CV functions. I will only be using the CV’s that are associated with a basic steam engine and thats all. All of my Turnouts are either operated by hand operated brass switch stands or servos using a very simple control board that I make for about $4.00 each and these will be wired directly to the control panel.

So I am using an old school method of DCC power reversing for the Turntable. It is simple, not overly complicated and I am sure that it will work and be reliable in the long run.

not sure how to post pics here, so this is the link to my website and the page when I have the wiring diagram. http://www.danstrains.net/my_layout_dcc_wiring.html.

I am open to any suggestions and improvements as long as it does not involve expensive DCC automation and JMRI. My Layout will not be connected to a computer in any shape or form.

Dan

It’s OK to be “old school”, but at 75 “new school” is pretty darn nice. I run NCE DCC on my HOn3 layout and it has the automictic reversing unit and it’s wonderful, you just run the trains and all is done for you, my large scale is now all battery powered and RailPro, so as you can see reversing problems just don’t exist anymore on either system. I’m not a big electronic guy either, but installing the systems correctly and following the instructions will defiantly give you the railroad you always wanted and wonder why I didn’t do this earlier.

trainman

#9

John Some of my Large scale trains, the Bachmann Big haulers are also battery operated with my Home made DCC++ systems based on the work of Dave Bodnar and his designs on http://www.Trainelectronics.com. you can see my version on my website. http://www.danstrains.net/wireless_dcc_plus_plus_system.html I can run them inside, but I usually run them outside and also let the Grand Nieces and nephews run them and not my Large scale Spectrum trains. I could install a DCC reverser and may eventually do that, but right now, to me a simple DPDT $4.00 switch out weighs the cost of a $25.00+ DCC Reverser. I would rather spend the extra money on more scenery materials and details and keep the wiring to a bare minimum.

Dan

Colorado & Rio Grande Southern

http://www.danstrains.net