Hey guys, so I am building an HO scale layout and I want to include a turntable. I plan on converting the layout to DCC at some point. As far as the turntable, I want to either power motor on a seperate system all together or just make in manually opperated. But I have two questions-
1: Is there anything different I need to do to power the tracks themselves with DCC?
2. I plan on using the Walthers 90' HO turntable kit. Is there any additional electronics or hardware that I might need that won't be included?
The kit you're talking about, if it hasn't changed substantially in design (but is considerably improved over the early 2000's version I finally gave up on), will not reverse the polarity of the bridge tracks as it rotates through 90 degrees. So, you will need to reverse them yourself...probably best done by using an auto-reverser in series between the main power bus after the output terminals of the base unit to the layout and the feeder wires that power the bridge tracks. Or, maybe simpler to use the AR on just the bay tracks inside the roundhouse if you will have that (you will need to gap the lead at some point, probably best after the turnout affording access to the lead). Your call.
Unlike DC, where polarity is a problem, the AC current of DCC is actually going to have a phase problem...but it amounts to the same effect when it happens. So, yes, you must reverse something between the bridge rails that will switch through 90 degrees on either side of the lead track.
Other than that, the rails with DCC will behave like normal, and the trains will as well.
Thank you
selectorOr, maybe simpler to use the AR on just the bay tracks inside the roundhouse if you will have that (you will need to gap the lead at some point, probably best after the turnout affording access to the lead).
.
I am out of my element here, but this brought up a question.
How would it not be simpler just to have the reverser on the bridge track? Then hard wire the approach track and the radius tracks to the roundhouse or garden?
If you install the reverser on the radius tracks would you also need a reverser on the approach track?
-Kevin
Living the dream.
selectorprobably best done by using an auto-reverser in series between the main power bus after the output terminals of the base unit to the layout and the feeder wires that power the bridge tracks.
conventional approach make the bridge a reversing section and use an auto-reverser to align the polarity of the bridge to the track being crossed regardless of bridge orientation.
agree with Kevin, doesn't sound simpler at all !
greg - Philadelphia & Reading / Reading
Considering the turntable will have 2 wires to poower the tracks on the bridge, and considring the bridge is by definition already isolated at both ends - it makes no sense to connect the autoreverser to the stall tracks, nor would it be any easier to wire. It would also fail to solve the problem unless all the lead in tracks were ALSO gapped and connected to the autoreverser.
A turntable already provides you with an isolated section of track to use with the AR, with no effort beyond installing the turntable in the first place. No gaps to cut, no insulated joiners to install. And no way for more than one loco or lighted car to cross the gaps at the same time - a perfect isolated reversing section.
What you might want to sonsider is switching power to the stall tracks, so you don't accidently select the wrong address and drive a loco into the tunrtable pit or attempt to drive it through the back wall of the roundhouse. If you are wiring the layout for DC at first, you'll already have this wired so you can park locos in the roundhouse. Keep the switches when you convert to DCC.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
rrinkerconsidring the bridge is by definition already isolated at both ends
!
rrinkerIt would also fail to solve the problem unless all the lead in tracks were ALSO gapped and connected to the autoreverser.
don't understand how any additional gapping requires anything less than two auto-reversers (including the bridge)
If the stall tracks and the approach track were run through an autoreverser, and the turntable bridge was not, you would need gaps in the approach track to isolate it from the rest of the layout. So, each stall track, plus one loco length of the lead, from the bridge out. You have to isolate the lead track because if you come in off the lead and spint he loco 180 degrees, the bridge and the lead will now be out of phase and need to be reversed.
Just more reason NOT to do this, WAY too complicated for absolutely no benefit and in fact, more cons than pros.
so you're surrounding the thing that reverses polarity with sections controlled by an auto-reverser, instead of controlling the bridge polarity with an auto-reverser.
now i understand.
gregc so you're surrounding the thing that reverses polarity with sections controlled by an auto-reverser, instead of controlling the bridge polarity with an auto-reverser. now i understand.
That was selector's "maybe it is simpler.." idea. Not simpler. AR to turntable bridge feeders, and you're done, nothing could be simpler. Well, if the turntable has split ring pickup and you can deal with a blip in the sound of a loco being turned - then you don't even need the AR. That's even simpler. But the OP's turntable does not use split ring pickup.
I made a disk which has a "high" and a "low" cam area. A Microswitch follows the cam with the turntable rotation. A DPDT relay is activated by the Microswitch. The DPDT is wired as a reverse switch and feeds the turntable bridge rails.
I installed it 25 years ago and never had to do anything else to it. It just works. Originally on DC but no modifications were needed for DCC.
TT_drive by Edmund, on Flickr
The 5" dia. disk is shaft mounted and the Microswitch can be seen to the right of it. Never fails. I use a New York Railway Supply stepper motor drive and the control has a built in reversing relay that can be programmed but I've never used that feature.
Good Luck, Ed