There is so much wisdsom and experience here in the forum that I'd like to borrow some.
I'm about to install a Walthers pre-DCC 130' turntable (model #933-2829) and a 9-stall roundhouse, all of which I've been waiting years to use. I can't afford a newer turntable that might be fully DCC-operable. The stall tracks must obviously be powered, but I haven't decided whether individual tracks should be power-switched to be able to turn them off completely. Most locos are sound-equipped. Roundhouse lights, all LED, will be powered and switched separately from track power.
The issues I know about are the need to reverse phase on the turntable bridge, amperage load with a full roundhouse of sound-equipped locos, and the fact that my turntable is too old to use the more recent Walthers DCC turntable control system.
I know there are questions I haven't even thought of yet. Among those I have considered are:
1. How to wire the track power for the bridge and stall tracks so they all appropriately handle phase reversing, as well as the track leading to the turntable.
2. Easiest workable ways to turn stall track power on/off individually to save amperage.
3. Best auto-reverser to use.
4. If there's any way to get the older turntable control to respond to DCC input for rotation and track alignment. My plan is to power the tuntable drive separately from track power, but everything about the turntable and stall tracks isn't locked down until I read the responses from you good people.
5. I bought a PSX-AR planning to use it for the turntable. Should stall track power as well as turntable bridge track power come off this unit, or should stall tracks be off the power district bus like any other track, without worrying about phase reversal because the bridge track auto-reverser will manage this?
I have a 10-amp NCE Powerhouse Pro command station, broken into power districts using PSX circuit breakers that allow setting power district trip amperage individually. The PSX-AR I got for the turntable would allow the table to operate as a separate power district, which might be advisable given the number of roundhoused sound locos expected, with the stall tracks gettting power from this breaker along with the turntable. Wondering how others have handled this sort of thing.
Believe me, all comments, observations, suggestions and insights will be wildly appreciated. Thank sin advance for your responses.
I have the 'indexed, built up' version of the 90'er. now 16 years old.
To keep things 'in line', figure out which end of the bridge will be the A end. That goes to the approach lead, and it should be wired the same as the lead rails. The radials all have an A end, and it's the bridge lip end. Imagine a loco approaching, moves onto the bridge, and the B end of the bridge swings in arc a few degrees, at which the loco trundles off onto the aligned radial and you shut it down. No conflicts with phase.
But, you reverse the bridge, and now you drive off the loco reversed and onto a radial. You would have a phase conflict, correct? No. Unless they had a huuuuge brain fart, the people at Walthers made the design a 'split ring' design that automatically reverses the phase up to the bridge rails after the bridge rotates past 90 deg either direction. So your loco will be able to reverse onto the radial as you intend.
The trick with wiring the radials is that the ones closest to the approach lead, on either side of it, will get the same left/right wiring orientation. After 90 deg either side of the lead, your split ring will reverse itself and thereby the phase up to the rails. So, your radials past the first 90 deg either side will have to be wired the same as the lead as well. With the two rails reversed, the rings reverse them back again, and they will be in phase with the lead once again. So the bay tracks and opposite radials should not have their phases reversed at the bus, or by their feeders.
I don't believe you will need the PSX-AR, unless I am wrong and Walthers no longer splits the power ring under the bridge. Someone will know, but if you own the 'indexed built-up' design of around 2007/8 or so, you're good to go.
The bridge gets DCC power by design. Part of the powering hub at the center of the bridge includes two wipers on rings that get power up to the rails. It's the very same DCC signal that the rest of the layout is getting. That's because you're going to put feeder ends into small receptacles on a black box and provide the bridge with DCC the same way you do the rest of the layout. The drive mechanism is a separate box and you'll have to get your own suitable power supply for moving the bridge. At least, that's what I had to do.
You should consider, and I mean this emphatically and sincerely, figuring out how to cut power to the radials and bays. Use a selector, wiring in many DPSTs, or whatever, but you really do not want even idle, muted, locomotives drawing power they don't need to parked for days or weeks on the radials and in the bays. Even with 10 whole amps. It's just a recipe for a couple or six scrambled decoders which get power spikes every time you put power to the rails for some reason.
Navyman,
I have the 2829 and it has worked very well for years. The bridge track power is obtained directly from the DCC track bus with no reverser needed. Reversing occurrs automatically in the dead zone. The dead zone is an area a few degrees wide in the bridge rotation that no radial tracks may be positioned. If you still have the original documentation the dead zone is clearly indicated.
The bridge motor and control box should be powered from a separate source. I use a 16VAC doorbell transfomer available from hardware stores etc.
The approach and stall tracks must be wired to agree with the bridge track. I don't recall exactly how I determined the correct phasing but it's easy to deduce by a quick trial. It's best to wire your approach tracks first, then connect the track bus to the turntabe and reverse if necessary. Same is true of the stall tracks but they will all be the same as viewed from a train on the bridge headed onto a stall track.
I have 9 radial tracks and use a 10 position rotary switch to control stall power. Just connect the same side of all stall tracks together and to one side of the DCC bus. Route the other side of each individual stall track through the corresponding position of the rotary to provide power to that track The tenth position on my switch is OFF. You could use individual toggle switches if you want more than one track powered at a time but I don't. You can also use an additional pole on the rotary to control indicator lights but an LED connected through an appropriate resistor to each track and protected by a reverse diode works very well.
The 2829 control is pre DCC and not compatible with DCC commands. You'll have to press and hold the buttons. Sorry. That said, I find it much easier to push turntable buttons than to figure out and enter commands from the throttle, unless of course you're into heavy automation.
Let me know if you need more help. I also have the original manual and a digital template if you need them.
Charlie
One thing to consider if using a rotary switch is that whenever you turn the switch to select a track every track that the switch passes through gets power momentarily. This may or may not be objectionable. You could use a separate SPST toggle switch to kill power to the rotary switch until the track is selected.
That's true but I haven't found it to be a problem. Many newer decoders won't repond at all until addressed but even older decoders don't seem to be a problem. No engine movement or sound detected. However, if you're using the switch to light LEDs for position indication you will see quick flashes. Probably not a problem.
I have the Walthers pre-DCC 90' turntable and an 11 stall roundhouse. No auto reverser is needed. If the turntable's dead zone is between the turntable lead and the roundhouse stalls, you might need to reverse the wires on the roundhouse tracks from those on the turntable lead. If not you probably won't.
Best thing to do is wire the lead and turntable, then temporarily wire one stall track. If the loco shorts going from the lead to the turntable, reverse the turntable wires. If that transition works fine, test the turntable to roundhouse stall track. If it shorts there, reverse the stall wires. If not, you're good to go. Wire the rest of the stalls the same as the first one.
I have half a dozen sound-equipped locos in the roundhouse at any one time, and all the tracks are always powered. I've had no problem with overtaxing my NCE 5 amp system. When I need to, I'll add toggle switches into the stall leads so I can power only one stall at a time.
Personally I wouldn't use a rotary switch for stall power selection because I wouldn't want those fast transient pulses hitting my decoders as I switch between stalls. Those transients also hit the DCC system. Probably never be a problem, but I just don't want to stress the system or decoders with those pulses.
Mark P.
Website: http://www.thecbandqinwyoming.comVideos: https://www.youtube.com/user/mabrunton
PruittPersonally I wouldn't use a rotary switch for stall power selection because I wouldn't want those fast transient pulses hitting my decoders as I switch between stalls.
I've used a rotary switch for stall track power (only one rail switched) and haven't had any of those problems since I wired a SPST switch on the common to the rotary.
IMG_4968 by Edmund, on Flickr
IMG_4962_fix by Edmund, on Flickr
For the bridge itself I made a disk that acts as a cam. A Microswitch rides on this cam and energizes a relay which reverses the rail phase as the TT turns past the 180° point. I guess an AR-1 would work, too, but I had this setup since I installed the Diamond Scale turntable back in 1995 and it still works after converting to DCC in 2005.
TT_drive by Edmund, on Flickr
Good Luck, Ed
Navyman, I have the same setup as you do, same turntable and a 9-stall Walthers roundhouse.
The earlier post by Charlie pretty much explain most of what you need to know.
Most importantly, you do not need an auto-reverser since the turntable is designed with a split ring to automatically reverse polarity.
The fact that the turntable is pre-DCC has never been a problem for me. The "indexing" feature allows you to pre-program the stopping points at the desired stall. The one annoyance is that the turntable will stop at each stall on the way to the desired stall. I solved that problem early on my disabling all the stop points and I now operate the turntable "manually". What I mean by manually is not turning the turntable by hand but rather by holding the button down on the control box until the bridge reaches the desired stall.
The wiring is fairly straightforward. The tracks are all wired to the DCC bus. However, the turntable bridge requires AC power, so I use the AC side of a power pack for that purpose. If you wire LED lighting to the interior, you can use the DC side of a power pack to save DCC power.
By the way, you don't actually wire the bridge track. That is done internally when the turntable is initially wired to the control box. You can actually lift the bridge right out of the turntable pit for cleaning purposes.
Rich
Alton Junction
I thought that I would write a separate post to describe a special situation in which an auto-reverser is required to avoid a short.
Years ago, I had a setup in which a short occurred on an approach track to the turntable. Here is a diagram of that setup.
I could never figure out why I needed an auto-reverser, so I started the following thread.
https://cs.trains.com/mrr/f/744/p/181396/1987593.aspx#1987593
Another forum member stepped in and solved the mystery.
Here is the answer as posted by Dave Merrill:
Rich,
Bingo!!
The answer to your problem is in the text of your last post. The 'dead zone' is at 9 o'clock under the yellow crane and straight across between two tracks at 3. Your approach tracks are at 8 o'clock and 4 o'clock. That puts both approach tracks on the same side of the 'dead zone'. On the left 8 o'clock approach track the red feeder is closest to the 9 o'clock dead spot and on the right track 4 o'clock the blue feeder is closest to the 9 o'clock dead spot.
Hence both approach tracks approach the same half of the TT with the feeders on the right approach track reversed in relation to the left approach track. A short every time.
The dead zone divides the TT into two electrical components. All tracks approaching each half must be wired the same. If the 'dead zone' (no-track) was between the roundhouse and engine shop you would have no reversing issue. Probably not worth the effort to rotate the TT or re-route the right approach track to be at the 2 o'clock position, either of which would eliminate the reversing issue.
That explains why the AR is needed.
This is, admittedly, an unusual situation which can be avoided in most situations.
I'm a huge proponent for switched roundhouse tracks for a few reasons. Not only the drone of the diesel engines idling and the steamers clanging and hissing with the random sounds.
Safety of the locomotive and roundhouse crew. I couldn't tell you how many times I thought the spotted locomotive was in speed step 0 instead of 1. You wouldn't want your locomotive to take out the back wall of the roundhouse or end up in the TT pit while you were busy elsewhere. This usually happens to me with the switcher for the gravel plant while swapping between the plant and the scale track switcher. My former club had a roundhouse wall and roof collapse from a unattended idling locomotive left in SS1. The repair was uncomfortable to do due to it's distance from the edge of the layout.
Just my 2 cents.
Pete.
I think Rich's post captures the salient point of track layout. The TT is divided into two halves by the dead zone. The dividing line is across from, and perpendicular to, the zero point sensor. Make sure all tracks in each half are wired the same and make sure no tracks are close to the dead zone. The dead zone is small but not zero. On my layout all stall tracks are on one half and the two approach tracks are on the other half. Works like a charm.
I had the pre-DCC version of the turntable and the reversing is built into it. No need for a separate auto reverser. Just avoid putting any tracks at the zero point on either side of the TT.
Eventually the controller fried and I have obtained the DCC version of the TT to replace it. It's still in the box so I haven't had a chance to look at it to see how it might be different electrically.
I second the motion for an on off switch for the roundhouse. No need to have those locos drawing power when they are idle. I'm going to add one to the ready track on the servicing section leading away from the roundhouse.
I have a three-stall roundhouse with a few extra stall tracks outside to increase capacity. Each stall track is separately controlled by a SPST toggle.
It takes an iron man to play with a toy iron horse.
I use a simple ON/OFF toggle switch, in conjunction with a rotary switch to control the stall tracks in my roundhouse and for the multiple tracks at the Lowbanks locomotive shops....
The ON/OFF switch is OFF while the rotary switch is turned to the desired track.
The turntable bridge track is controlled by a double-pole/double throw/centre-off switch, which controls only the direction on the turntable. The turntables at both facilities are not otherwise electrically-powered, as rotation and alignment are done using finger-power.
Wayne
I installed an on/off switch for each stall. Works for me. I have about 10 stalls.
Simon
I have the same turntable. The only annoying thing is the power cut off as your turntable passes through the "No track power" section. Minor inconvience if you have a sound decoder. But I solved it by ripping it apart and putting a slip ring in the base instead. Now I have continuos power and fix the track reversal with an auto reverser.
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
As always, the wisdom and experience of the community, and your generosity sharing it, is a life-saver. Thanks, all, for your very useful responses. Now I can set things up without worrying about breaking anything! Tyanks again!