Jerry Leone in his “Back on Track” video series makes reference to a system detailed in the November 2000 Model Railroader for Route Control for Tortoise turnout motors. Radio Shack does not seem to have the center-tap transformer referenced in the article, and a search brings up about 22,342 options which is mostly confusing to the “non-electrician me.” Isn’t the Internet a wondrous option?
I did find one however that may be what I need, though it’s only 6v DC output 300 mA.
If I’ve heard and understood things correctly Tortoise machines will operate on 6 volts, slower than with 12 volts but many think of that as an advantage. And 300 mA should power a lot of machines - for my application I’ll have eight double-ended staging tracks, so 16 Tortoise. Is this the transformer I need? Or can someone point me in the direction of one that does meet my needs?
And because I came here before I adequately did my research, the article calls for a 1-pole 12-position rotary switch. Best options for that perhaps?
I di not have access to the 2000 MR issue you mentioned so I can’t comment directly, but it sounds like it requires a dual polarity power supply. That would be the reason for a center tapped transformer. The dual polarity supply (=/- 12 VDC) is nice in some respects but not at all necessary for Tortoise operation. On big layouts it can save some toggle switch cost (single pole vs double pole) but today the savings are minimal. I can refer you to the May 2009 issue of MR in which Oliver Tansey describes a route control system for Tortoises that works very well. It only requires a single polarity 12V supply and a single pole rotary switch with the number of positions equal to the number of routes you plan. I am using this approach several places on my layout and it works very well. The only drawback to it is a bit more complicated wiring under the table and the addition of 2 resistors per Tortoise. There is also a slight delay when waiting for several switch motors to move is sequence but it’s by no means objectionable. A lot faster than the prototype with one or two switchmen [:)].
For the rotary switch I suggest looking at Digikey. They sell several versions by Grayhill. You can get the with adjustable numbers of positions so you expand or contract as your layout changes. Price is around $20 for a single pole 2-12 position switch. If you add asecond deck (pole) you can easily implement an LED route indication for the control panel.
As for transformer rating, each Tortoise will draw a little more than 20 milliamps at 12V so 16 would slightly exceed yor 300Ma transformer. However that’s for 12V. 12V 1 Amp transformers should be redily available but many folks use “wall worts” which are really easy to find.
Obviously my brain outruns my fingers when typing. I hope you can wade through the typos and get the jist of my comments. I wish there was a edit capability on this forum.
First, I don’t see any edit button on the existing posts, even on mine after I log in. The only edit button I see is on the reply composition page. and is of no use after I post and discover a goof.
Second, the posted schematic is the basic diode matrix approach. I hate diode matrices.[:(]. The OP has 8 routes so the matrix will require a large yacht load of diodes. The beauty of the approach I suggested is all logic is handled by a single pole switch and the switches built into the Tortoises. The only price paid is a third wire to each tortoise, the sacrifice of one pole in each Tortoise, two added resistors per Tortoise pair, and the need for a second pole if a route indicator light system is desired. There is also some delay is cases where several motors must actuate in sequence but this should not be a problem for staging situations. The delay becomes noticeable in a yard where lots of fast switching is happening, but a staging yard should be OK. I suggest the OP take a look at the article if it is available and report back here. There’s plenty of expertise available on this forum [:)] [#welcome]
Thank you all for everything to this point. I have a .pdf copy of the Nov 2000 MR article which might be of help. Is there a way to attach that file to this discussion? And would doing so violate MR copyright needs?
More clear specifics of what the article’s author is asking for are:
12.6V, 1.2A center tap transformer
Silicon diodes, type IN4001 (quantity 2)
4700 mf electrolytic caacitors (quantity 2)]
2.2k - Omega symbol - 1/2 watt resistors, (quantity 14)
1 pole, 12 position rotary switch
Tortoise machines, knob, 5 lug terminal strip which is optional
I understand that there is way to control staging yard track with a matrix system, but this system seems rather simpler and more elegant.
Robert
PS I did not see in the Forum editor a way to insert that Omega symbol in reference to resistors. Nonetheless it took me back to my college days of learning Greek. Turns out I am quite happy with having that part of history behind me. Though I am tempted to think about going back and reading an ancient Greek work on the fear of foreigners which we were required to translate, the word “xenos” has something to do with the title. We get our word “xenophobia” from the same place. Just need to get some stuff in my head these days.
I can refer you to the May 2009 issue of MR in which Oliver Tansey describes a route control system for Tortoises that works very well. It only requires a single polarity 12V supply and a single pole rotary switch with the number of positions equal to the number of routes you plan. I am using this approach several places on my layout and it works very well. The only drawback to it is a bit more complicated wiring under the table and the addition of 2 resistors per Tortoise. There is also a slight delay when waiting for several switch motors to move is sequence but it’s by no means objectionable. A lot faster than the prototype with one or two switchmen .
So the “Second Lesson Learned” here is to read the post of an expert carefully enough to get it all in your head. I just picked up the reference to the plan from the Tansey May 2009 MR article and I much like his “Dendritic Control System” version B (and in addtion here I get to use some of the Latin I had to learn in years gone by). I’m thinking that’s the approach that makes the most sense.
And I’ve figured out that what I really have are two staging yards side by side. The double track mainline runs through the center of the yard with a four-track yard ladder attached to the East mainline and a two-track yard ladder attached to the West mainline. Putting one Dendritic system on the East yard and another on the West yard means I really only need six (6) routes controlled by rotary switch power, four for East, two for West.
So my next question for CharlieM is do I need to use Tansey’s Version B with his micro-switch system controlling subsequent motors, or can I get away without the microswitch and wait for motors to throw on that four ladder yard? Or to put it another way can I stretch “with two to three turnouts in a row” to “with three to four turnouts in a row”?
My first question would be why not use Tansey’s version A? The Tortoise has two sets of internal contacts that work well and avoid the diode issues. I typically use one set of contacts for the “dendritic” control and the other to power the frogs. Panel lights can be controlled by a second pole on the rotary switch. Unless you’re heavily into trackside signalling systems you can afford to use one set of Tortoise contact sets for route control. However I would give the fourth Tortoise a try if you have to go with the diodes. The neat thing is the motor draws much less current while moving than when stalled. With three sets of diodes in series (four Tortoises) and starting with 12V the last motor would see 9.9V (12-3x0.7=9.9). The 560 ohn resistors will further drop this but the motor will see almost the full 9.9V while it is running. When it stalls there still is plenty of current available to hold it in position. I’ve read where some guys run tortoises on 6-7V but things slow down. That said, I still would try to use the Tortoise contacts and avoid diodes and micro switches.
You’re in good shape with 6 or less positions on each side. The Grayhill switches are available in 2 pole, 2-6 position models; one pole for route control and one pole for panel lights.
Certainly not for the final time in my life someone asked the question I needed to hear. When I was aiming toward Tansey’s Version B it was because I wanted to keep one set of terminals on the Tortoise machines open to use eventually with some kind of trackside signalling systems. Then the question sunk in, and why would I ever need trackside signalling in a staging yard? Go figure.
So Version A looks sweet, though I will use 2-pole rotary switches so that if I ever want to add panel lights for the staging ladder tracks. You are good, sir, if you can get me to understand what’s going on without the use of bat or a brick.
Thank you.
“Then the question sunk in, and why would I ever need trackside signalling in a staging yard? Go figure.”
I wondered about that too but didn’t want to insult your intellegence [:)]. Who knows? Maybe you wanted to put a camera on the engine to check the signals in the staging yard. [:O]. Anyway I’m glad to have been of service in opening a door for you. One “advantage” to the version B is that all Tortoises begin to move immediately. Version A powers each tortoise only after the previous one has reached its final position. Usually not a problem but sometimes noticeable in a large yard. However that advantage is not enough to nudge me toward version B. BTW, Tansey does note that the version B limitations can be overcome with more complexity and more diodes. Do I hear diode matrix in the wind? Anyway, please report back on your progress and don’t hesitate to ask more questions.
BTW, I usually put the resistors on a barrier terminal strip near the edge of the layout near the control panel. I then run just three wires to each Tortoise (pins 1,5,8). This allows all kinds of flexibility in wiring and future reconfiguration.
since i don’t have copies of the articles, would if be possible for someone to post schematics (possibly hand draw) of the two approaches being discussed?
