I need help. I just installed the Walthers 130' DCC turntable.
When the loco reaches the bridge it shorts out. I tried taking out the bridge on flip it 180, and still get the same thing.
I wired it according to the directions.
There are 4 terminals.
The inside 2 terminals number 2 & 3, are connected together, and then going to Rail A on my DCC booster.
The outside 2 terminals number 1 & 4, are connected together, and then going to Rail B on my DCC booster.
The turntable works fine, if I just place the loco on the bridge. And it works using the DCC address of the positions that I programmed.
Please help!
Michael
CEO- Mile-HI-RailroadPrototype: D&RGW Moffat Line 1989
Michael,
First thing to try is to reverse the polarity of the track power to the control box. Rotating the bridge 180 degrees will make no difference because the split ring will switch track power at the bridge.
Polarity of the power to the approach track must match the bridge track to begin. Then the split ring does the magic to keep it correct when rotating past the 'no tracks' (reversing point).
On my 130' TT there are 4 connections on the control box, the two closest to the bridge motor plug are track power and the two furthest away power the motor. Different numbering than you mention.
EDIT: Sounds like you have one of the new digital TTs which would explain the different control box, but the track polarity will still be the same issue.
Regards,
Dave
From Mt Pleasant, Utah, the home of the Hill Valley and Thistle Railroad where the Buffalo still roam and a Droid runs the trains
I agree. Your wiring of the lead to the TT and the wiring to the TT don't match. Switch one of them, most easily the ones to the TT. The reversing is done internally by the TT, but it is also reversing the loco which, after all, is what you want it to do.
Lead to the TT, the TT's bridge rails, and the radials all need to have the same polarity left and right. The only thing that changes is the bridge when it rotates, but all it does is make what was the left rail the other polarity, and what was the right rail its opposite polarity. That way, when the loco is swapped end for end, when it travels across the gap to one of the far radials, the rails still match up between the bridge and the radials.
Crandell
This thread reminds me of an issue with my Walthers 130' turntable which is the older non-DCC version.
Apparently, the spilt ring design is not a true auto-reverse unit. Whereas an auto-reverser will sense mismatched polarities and reverse the polarity of the bridge track to match the approach track, a split ring is strictly mechanical in the way that it matches polarities. Is that correct?
When I first installed my turntable a few years back, I added an approach track from my main line to the left side of the turntable and a second approach track from my main line to the right side of the turntable. This can result in a polarity mismatch on the right side approach track causing a short. I have never understood this completely, but I did have to gap the right side approach track and install an auto-reverser to solve the shorting problem. Does this make sense?
Rich
Alton Junction
A split ring system is supposed to have a short dead section in it, not just two simple gaps like you'd cut in the main line, otherwise the pickups on the carriage could span both sides and cause a short.
The rest depends on which rail each pickup on the carriage connects to. Let's assume that looking onto the bridge from the pit, the nearest pickup roller connects to the left side (if it's the right, simply reverse everythign that follows). In such a case, any approach track should have the rail on the left (facing onto the bridge) connected to the same split rail on the side of the pit it is approaching. All the way around - so approach tracks AND the stall tracks. No matter which way the bridge is spun, the polarity would be the same on the approach, straight across, and into the stall. And if the bridge is spun 180 degrees to turn the loco, the polarity would still match. In that dead area on either end of the ring rail, you cannot locate any tracks. There's possibly a slight area to eaither side of this dead zone where there could be a mismatch, depending on exactly where on the ring the pickups from the bridge ride.
If it DOESN'T work like this, it's either not a split ring pickup, but a continuous pickup system, or one of the other tracks has the feeders reversed from this description.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Wow thanks guys! I'm learning a lot how this thing works. Very interesting how the polarity changes, etc.
Thank god for you experts here, or I would be tearing my hair out right now.
When I get home tonight, I will reverse the connections on the control box. I hope that fixes it.
Will report what the results are.
Here is the turntable. I only have one lead track, there are no other lead tracks. This is just for turning the locos only.
richhotrain I have never understood this completely, but I did have to gap the right side approach track and install an auto-reverser to solve the shorting problem. Does this make sense? Rich
I have never understood this completely, but I did have to gap the right side approach track and install an auto-reverser to solve the shorting problem. Does this make sense?
Rich,
It has to do with the orientation between the approach tracks and the 'no-track zone' (reversing point). If you were to call one reversing point blue and the other point red and each approach track or ray track having a blue rail and a red rail, the blue rail of the approach/ray track must be on the side closest to the blue reversing point and the red approach/ray rail must be closest to the red reversing point.
If memory serves me correctly weren't your left and right approach tracks oriented like A and B with a work train parked on a track over the blue 'no track' area? Rotating the entire turntable assembly so that the red reversing point was between A and B would solve such an issue.
HTH
EDIT: Yup. It was back in October of 2010. Seems the wager was a cool six-pack.
Dave, I must confess, I all but forgot about that thread. I recall it all now. I guess that this current thread brought home to me the notion that the bridge track has to be initially wired in phase with the approach track to avoid a short caused by reverse polarity. That explains my situation with the approach tracks on the left and right, as shown in the photo below.
In the photo, I have lined up the bridge track with the "no track zone" so that track on the left of the bridge track is "dead". My approach tracks are the three tracks below the "dead track". The track coming off the turntable on the lower right is also an approach track. The approach tracks on the left and right are all wired in phase with the bridge track. For that reason, there is an isolated section of track between the right hand side approach track and main line track, and that isolated section of track is controlled by an auto-reverse unit to avoid shorts caused by reverse polarity.
So, back to my original question. The split ring setup on the Walthers 130' turntable is not really an auto-reverse unit, correct?
As to your point, Dave, if I had been able to route the right hand side approach track above the "no track zone", then I would not have needed an auto-reverse unit, correct?
I seem to recall one version of the Walthers turntable does have split ring reversing, the other one just has slip rings on the center shaft and thus requires an autoreverser or DPDT toggle.
If you had to isolate a section between the main and the approach track, it sounds like your whole roundhouse complex is out of phase with the main. Or is that part of the 'main' sctual on a reverse loop so it keeps getting phase changed? If you can back one of those locos out of a roundhouse stall, then spin 180 degrees and back in in to a stall, without traversing the section of track on the approach that has the reverser, then the turntable is handling the reversal in that area. If the turntable did not reverse proper,y the autoreverser would need to be connected to the bridge rails.
Yes, the split ring automatically reverses the power on the bridge rails as the bridge rotates through the no-track zone. Hence it is an analog automatic reverser.
The split ring is on the bottom of the bridge and rotates with it. There are two wipers in the base of the TT. Using my color drawing as a reference, these two items are located so that 'blue' power goes to the blue rail on the bridge for about 170 degrees of rotation, not including the no-track area. As the bridge goes through the no-track area the gap in the split ring crosses the blue wiper, then the other half of the split ring (formerly red) comes in contact with the blue wiper and the polarity is now reversed on the bridge rails, but still matches the approach/ray tracks on both sides of the TT. There is a momentary loss of power on the bridge as the gap in the split ring crosses the wipers.
Yes, had you routed the right approach track above the no-track zone you would not have needed an AR unit.
Looking closely at your picture if the no-track zone were just to the right of the 3-bay engine shop it appears that the other end would not have any tracks aligned. Is that the case, hard to confirm from the picture? If so it is possible to rotate the split ring assembly on the bottom of the bridge to align the no-track zone in the area mentioned and eliminate the AR unit. The plate to which the split ring is mounted can be pried from the bridge, the indexing tab cut off and the plate rotated to a different position, then re-glued. By trial and error you could move the no-track zone anywhere. If you choose to do that you would also have to flip polarity on several ray tracks to keep the blue/red orientation correct. Let me know if that project interests you and I can help with the details.
Aren't turntables fun? BTW how did you enjoy the beer, chips and cheese dip that October evening? I gather Randy didn't show up either.
Warm Regard,
Thanks for that reply Dave. The TT has been in place for about 7 years so I am not going to mess with it now.
I appreciate the explanation of the split ring. I guess what I meant about it not being an auto-reverser is the fact that the polarity of the adjacent tracks must be initially wired in phase whereas with an auto-reverse unit like the Digitrax AR-1 it doesn't matter since the AR-1 will sense the reverse polarity and correct the mismatch.
When you and Randy failed to show up, I drank the entire six pack myself plus the other three six packs since I had bought a case of beer. I don't remember much after that.
rrinker I seem to recall one version of the Walthers turntable does have split ring reversing, the other one just has slip rings on the center shaft and thus requires an autoreverser or DPDT toggle. If you had to isolate a section between the main and the approach track, it sounds like your whole roundhouse complex is out of phase with the main. Or is that part of the 'main' sctual on a reverse loop so it keeps getting phase changed? If you can back one of those locos out of a roundhouse stall, then spin 180 degrees and back in in to a stall, without traversing the section of track on the approach that has the reverser, then the turntable is handling the reversal in that area. If the turntable did not reverse proper,y the autoreverser would need to be connected to the bridge rails. --Randy
Randy, the much older Walthers 90' turntable did not have an auto-reverser or split ring setup. But, then came along the 130' turntable with the automatic indexing feature and that is the one that I have on my layout. It is a non-DCC version and it has the split ring setup as does the 90' model which followed.
Here is a crude diagram of my turntable setup. The dark brown feature above the turntable is the roundhouse. The dotted line is the "no track area". The curved line at the bottom is the mainline and the diagram shows the left and right approach tracks. Since the approach tracks are wired in phase with the bridge track, the right side approach track required a reversing section, drawn in red, to avoid shorting the main line track. All of the roundhouse tracks are wired in phase with the bridge track so I can do that 180 degree rotation that you mention without shorting.
Randy, one other thing that I forgot to mention.
All of the tracks that run onto the turntable are in phase with the mainline except for the right side approach track and the track right above it (see my prior photo) with that C&NW e-unit parked on it.
Hmm, if the right-side approach track is not in phase witht he main, that's why you needed the reverser there. Otherwise it should all match, regardless of turntable position.
As for the question on split rail, unless you make some really goofy wiring, a split ring rail is always an auto-reverse connection. It can't help but be. If you draw a circle, and cut it in two palces 180 degrees apart, then draw in the carriage bogies with one on one half of the circle and one on the other half, on connected tot he right rail of the bridge, the other tot he left rail, then slip it around, you will see that the polarity MUST change as the bridge rotates 180 degrees.
rrinker Hmm, if the right-side approach track is not in phase witht he main, that's why you needed the reverser there. Otherwise it should all match, regardless of turntable position.
When I first wired the layout and the turntable connection, I wired the right side approach track in phase with the mainline right up to the turntable. It shorted when a loco crossed the gap between the approach track and the bridge track. Dave's diagram confirms the problem with my setup which could be avoided if the approach track entered the turntable above the no track area.
rrinker As for the question on split rail, unless you make some really goofy wiring, a split ring rail is always an auto-reverse connection. It can't help but be. If you draw a circle, and cut it in two palces 180 degrees apart, then draw in the carriage bogies with one on one half of the circle and one on the other half, on connected tot he right rail of the bridge, the other tot he left rail, then slip it around, you will see that the polarity MUST change as the bridge rotates 180 degrees.
Yep, I realize that the split ring setup effectively reverses the polarity. But it is not automatic like the AR-1 and similar units which sense the mismatch. I consider the split ring more of a mechanical polarity reverser, particularly since you initially have to wire the adjoining section in phase.
Interesting topic guys, I have not yet wired up my TT, but it is in position. I only have one approach track to the TT, a 3 stall roundhouse on the opposite side of the approach track, and two storage tracks along side of the round house. My TT is the Walters 130' non DCC. All my feeder wires in the roundhouse, and on the two storage tracks are wired to the main bus the same as the approach track. In other words, all the right rails (red) wired to the red bus, and all the left rails (black) wired to the black bus. So I guess my question is: When I wire up my control box, will that give me a problem? I'm not quit that far along on my layout to wire the bridge track yet, but I want to be sure I have my feeder wires soldered to the correct rails before hand.
Thanks
Sam
ollevon Interesting topic guys, I have not yet wired up my TT, but it is in position. I only have one approach track to the TT, a 3 stall roundhouse on the opposite side of the approach track, and two storage tracks along side of the round house. My TT is the Walters 130' non DCC. All my feeder wires in the roundhouse, and on the two storage tracks are wired to the main bus the same as the approach track. In other words, all the right rails (red) wired to the red bus, and all the left rails (black) wired to the black bus. So I guess my question is: When I wire up my control box, will that give me a problem? I'm not quit that far along on my layout to wire the bridge track yet, but I want to be sure I have my feeder wires soldered to the correct rails before hand. Thanks Sam
Sam,
You should be fine since all of your tracks are wired in phase, and all of those tracks are stub ended except for the single approach track.
What causes a problem on my layout is the specific location of one of my approach tracks on the turntable that connects to the mainline.
If you study Dave's diagram, the problem becomes clear.
Use the blue/red color drawing to confirm where your 'no-track' zone should go. Call one 'no-track' zone on the turntable 'black' and ensure that all black feeders are on the rail closest to the black no-track zone.
The objective is to have your approach and ray tracks match like the drawing. Switching the polarity to the bridge is a simple task.
As Dave indicates, the positioning of the "no track area" can be critical to your wiring efforts.
Unfortunately, when I installed my turntable on my current layout back in 2007, I was careless in the way that I positioned the turntable relative to the "no track area".
I wish that I had Dave by my side when I positioned the turntable. My advice to you is to study Dave's diagram before you finalize the wiring of that turntable.
Thanks Rich & Dave. I think I'm good to go.
Rich, that is some fine work on your turntable and roundhouse, looks great.
Michael, Really nice weathering job on the TT bridge.Hope you don't mind, but I'm going to copy you.
On that 'automatic' - devices like the AR-1, PM42, PSX-AR, etc. actually wait for a fault, then attempt to correct it. An approach like a split ring rail PREVENTS the fault in the first place. If you happen to read MRH, the current issue has an article on doing just that - changing reverse loop polarity via relays activated by Tortoise contacts (saves the Tortoise contacts) so no AR needed - there never is a short in the first place. There was also a discussion on this in I think the Digitrax Yahoo group recently. Overall a sound option - simply don't allow any sort of fault condition in the first place. A big advantage is that it always works, isn't affected by a varying load (single non-sound loco vs a triple header with sound, or something like that), and will never have even the slightest hesitation when crossing the gaps. Oh, and cheaper than an AR unit, too. It's all still 'automatic' in the sense that there are no toggles to flip, just like anywhere else on the layout, you line turnouts and just drive the train.
It works! It works!
I just reversed those connections on the control box, and now its all good. No shorting.
Thanks everybody for all the help!
Video coming soon....
I was going to tell you I had the same issue when I installed mine and switching leads fixed the problem. Hope you enjoy yours as much as I enjoy mine.
Curt Webb
The Late Great Pennsylvania Railroad
http://s1082.photobucket.com/albums/j372/curtwbb/
Here's a video I just shot.
http://www.youtube.com/watch?v=CNwc41vOYmk
Fantastic !
Now, get to work on the rest of that layout. I am getting tired of waiting for results.
I noticed that Walthers has not posted the complete new DCC Turntable manuals on their product site
They are missing the 4 pages that deal with the DCC and DC wiring options to connect the turntable.
It sure will cause confusion with those who loose their original instructions and years later need to re=install the turntable. That is when you think you have the instructions but do not have the section specific to the wiring of the turntable in either the DCC or DC options.