Walther's turntable has that no track section where the rails on the bridge lose power. This is slighly annoying when you have sound.
Question: Has anybody considered gapping the rings and putting an auto reverser on the track power supply leads?Obviously this would only work on DCC layouts.
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
I have one of the Walthers turntable (N scale) and I have no idea how you could do this.Wouldn't it be more feasible adding "Keep Alive" condenser(s) to the loco?But then,these TTs turn slowly so would a KA condenser hold long enough?Good question.....
They do 4+ seconds when the loco is running, with no motor load (the majority of the current draw), the keep alive should keep the sound going for 9-10 seconds at least, which should be plenty of time to pass the "no track" zone and regain power to the bridge.
I don't have one yet, but I have considered just making the bridge constantly powered. Not sure i will get a Walthers turntable, but it is one of the most cost effective ones. I plan to have mine near the layout edge, so all the automatic indexing is not really something I need - so I may go with a different TT, and just put a basic DC motor drive on it for manual movement.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Hey Randy,Keep alive is a wonderful idea until I get all 180 locos retro fitted.... Turns out it may not be an option anyway. Only 1 ring is gapped. one half is the left leg, the other half the right leg. So that won't work.My only other option is to have a low switching time DP DT switch which throws a relay to a charge capacitor when the power blinks. This would send DC to the loco, but keep the loco alive. This would require me to disassemble the bridge.
Question...what happens if you feed momentary DC to a DCC decoder?Won't it switch to DC operation and forget its previous digital commands?It wouldn't work for me anyway,as I turn DC off on all my decoders.
I have a similar turntable (N scale,not installed yet) so I believe I'll have the same issue.Your question has me thinking....
The only solution I can see,as of now,is to use the center overhead structure to install a pair of concentric slip rings linked to the bridge tracks.Then install a horizontal power pole (carrying DCC through an AR1) coming from the roundhouse roof (or other structure) holding wipers the the slip rings.
This way,the AR1 would read track power all the time and react to polarity changes when required,and still keep DCC to the track even when the turntable isn't supplying.Testing required...I think it would work though.
I would not do both - either build the overhead structure (which is prototypical anyway) and connect that to the bridge rails with an autoreverser, or use the stock feed, but not both at the same time.
Indeed,the current from the bridge wouldn't be needed as the AR1 would trigger when the loco jumps either of the TT's edges to match the bridge polarity with the stationary peripheral tracks.
However,I don't think leaving the TT's circuitry active would hurt either as the AR1 would match the bridge's polarity in whatever position it would be,still filling the T's void in between.The bridge then becomes sort of a switching device.
In the end it's a choice...polarity changes during the rotation or when the loco enters/leaves the turntable.The end result is same to me,as long as polarity shorting is handled correctly,you have a redundant system.
I could use a mini 1/8" mono plug in the top of the structure to connect the wires to the overhead. That would be more reliable then wiper plates
I have installed a Walthers 90 ft turntable on my layout. I am not happy with its quality and would not purchase another. That said, I do not understand your statement concerning the " rails on the bridge lose power". Both approach rails are powered and both bridge rails are powered thru brass contacts under the bridge. The problem is when the bridge is rotated the polarity in the rails becomes reversed. This can easily be overcome by connecting a Digitrak AR1 autoreverser between the bridge rails and the approach rails. I also connected the bridge rails to a DPDT switch to the turntable motor so as to allow rotation in both directions. No big deal.... Oh, I do use Digitrax DCC, but that is irrelevant to the issue.
Split Reduction
I don't know about the older designs but newer Walthers turntable have a transition area between polarities where there's no current at all to the bridge tracks.Not even noticeable with regular DCC engines,it becomes an issue with sound decoders wich shut down and re-cycle when current returns.Annoying indeed....
The problem isn't polarity,it's the lack of current.What was discussed so far in this post is a way to supply current continuously to the bridge tracks while keeping polarity under control.I haven't read about the result yet,but I think the OP will update us when he gives it a try.
Hmmm ............. I have the Walthers DCC 90' TT. The only loco I have with sound is an original edition BLI 2-8-2 with a QSI decoder. When on the TT and passing through the "dead zone," there is just a brief, barely noticeable interruption in the sound. It doesn't recycle, if by that is meant "start over." A tiny problem as far as I am concerned.
Dante
Some other sound decoders don't just pick up where they left off, they actually run through the whole loco startup sequence, which is a lot more annoying. Just picking up again with a brief interruption isn't so bad. Having the loco start up the engine again kind of is.
Even identical decoders will react differently depending on how they have their CVs configured.Some will automatically "idle up" upon track power while others will need a wake-up call from the controller to do so.
And then you have differences between steamers and diesels.Steamers don't have an engine cranking sequence wich,depending on CV settings,many diesels do.And if you're using prototypical "manual notching" (Tsunami),you have to wait for the startup sequence to terminate before the loco will move.
So...the turntable gap may be more or less annoying...results will vary.
Well I bought two 1/8" mini plug connectors. One had 2 connectors the other had 4. (I figured the extra two socket wipers would be good for redundancy on the connection)
Now I need to figure out how to get it to rotate without ripping up the connection wire. I'm playing with it now but the connections are a bit...tight.
Update:
I replaced the Walthers fingers and split ring with a Slip Ring. Contact is better and I now have constant power to the rails. A good solution for about $20.00 + an Automatic Reverser.I'll be posting a video and "how to" soon.
I'm not one to fill a thread with fluff, but darn that is nice work Mel.
Indeed...great work.I had come up with basically the same general idea in an earlier reply but hadn't figured out how to do it yet.I won't be installing my turntable for a while,but when I do,I will use this post...very good ideas...thanks for sharing.
Robert
The Tularosa Basin RR operating in the High Desert of Southern New Mexico
The Tularosa Basin: https://upload.wikimedia.org/wikipedia/commons/d/d7/Tularosa-Basin-NM-USGS-map_opaque.gif