Has anyone successfully wired the rotary switch for the WYE as described in the September MR article and shown in the schematic?
I am sure that I have wired a 3 deck rotary switch and 3 motors (slow speed stall motors - Switchmasters) according to the schematic but the turnouts (and therefore the routes) are not syncronized in the way described in the text. (I am only using two of the three decks of the rotary)
Only one route is sycronized correctly (B to C, using the naming convention in the article). A-C and A-B (main) do not occur.
Has anyone else had this problem?
Any suggestions on what protocal to follow to troubleshoot this? Seems like there are a lot of permutations and combinations of wires to test.
The first thing that I would look at is to be sure that you have a positive supply and a negative supply. That's two power supplies with one wire of each connected to ground / common. That can be easily missed.
If you put a voltmeter probe on common / ground (the up-side-down antenna symbol) and the other to -V, you should read a negative voltage. Then keeping the one probe on common / ground and putting the other one on +V, you should read a positive voltage.
If that is OK, then it is just a matter of making sure that the wires are connected to the proper points. The dashed line between the two switch decks is not a wire, just in case you didn't know.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
MR has been known to make mistakes in electrical articles with schematics through out the years. It may be that through the editing process, someone seems to think that the diagrams / schematics that are submitted have flaws, and the editor of the article knows best, and changes it. Either by design or accidentally. Also, changing a hand drawing to a computer graphic can come in to play as well. I know they do their best, but most of the time they don't build the circuits to make sure they are correct and work as the author says they do.
You have three choices. 1- Try and contact the author and get his diagram. 2- Wait for the next issue or two and see if there is a correction. 3- Try and figure it out yourself, or coerce someone to do it for you.
gandy: (may i call you gandy?) Funny you should say that. As your email came in, I was on the phone with another modeler who suggested the same approach (contact the author). Thanks. It's true, I have seen plenty of corrections over the years. Just my luck, this will be one of them.
At a quick glance it looks OK to me, if you are referrign to the schematic in figure 2, left side. I have it in front of me right now, and more carefulyl looking at it, it is correct as drawn. You only need 2 deskc of the switch. The center of Deck 1 goes to motors A and B, the center of Deck 2 goes to Motor C
In postion 'main', which is the A-B route, botht he A and B motors should be getting V+. Motor C, does not matter, and it shown unconnected. If motors A and B are getting the correct polarity from the rotary switch bot both are not lined for the main, flip the wires on the one night lined for the main.
In positions 'east' and 'west', both motors A and B get V- and shoudl both set the points away from the main. In 'east' , motor C shoudl get V- and line towards B, in 'west' motor C should get V" and line towards A.
I suspect from your description of the issue, the wires are the wrong way on Motor A. That would cause AB and AC to be wrong but BC to be correct.
Not sure what you mean by 'the center points are the same' - the center of deck 1 goes to motor A and B, the center of deck 2 goes to motor C only. Position 1 of deck one goes to V+, positions 2 and 3 of deck 1 go to V-. Position 1 of deck 2 is no connection, position 2 of deck 2 is V-, and position 3 of deck 2 is V+. It's actually a simple circuit, basic electricity here, no fancy electronics or diodes for routing power in any way, one of the benefits of using a bipolar power supply like that. Treat it as two seperate switches, one that moves motors A and B, the other that moves motor C.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I'll report back when I've tried it.
Since they cna go allt eh way around, they may indeed be mechanically flipped. However, if one is flipped 180 degrees, reversing the polarity of the motor terminals will accomplish the same thing as dismounting it and trying to turn it around. There's definitely no electrical difference using Switchmaster motors as opposed to Tortoises since in this edesign it is simply flipping polarity to the motors. Now for that circuit from a few months ago with the Torotises cacaded - yes, it would make a difference because resistors are used to bias the motor and pull a terminal high until one of the contacts closes on a machien upstream - the reistor values would have to change because the current draw of a Switchamster is different.
Randy and anyone following, here's an update.
MRR forwarded my questions to Dr. Hunt, the writer of the article, and we had a useful email exchange, wherein he explained that the polarity shown in the article (fig 2) for the various legs of the WYE were critical in properly constructing the circuit (this was specified in the first article, but I did not note the importance). He also described a simple way to determine the poliarty (which side of the motor to call negative or positive).
I followed his directions - which worked and seemed to indicate i needed to change the polarity of two of the three motors to match the drawing polarity. Then, I went back and re-checked all the connections against the schematic.
Unfortunately, the circuit is not giving me the results I want. So, I have abandoned the rotary switch approach, and decided to go with three SPDT's for route selection. I just don't have any more patience or time to devote to this one challenge.
Also, in reading the article again (and again, and again), i don't think the circuit is intended to do what I want.
My WYE leads to a branchline; and i want to be able to have a waiting train on the MAIN, between the A and B turnouts, when a train is going into (or coming out of) the wye from the opposite direction. It seems to me the circuit is intended to allow a train to wait on the other WYE leg.
Thanks for your (and everyone's) help on this.
Joel
If the 'wait' is on the wrong leg, you just need to rotate the diagram so the turnouts are int he positions you need for your track plan. The concept is exactly the same, and the degination of turnouts A,B, and C are totally arbitrary. If you can describe what you need on the basis of the A,B, and C labeles, the connections can be altered easily enought o affect the change you need.
Hi Randy: It would be nice to find out that's the case, so here's what I'm trying to do.
Main: Turnout A and Turnout B both line for the main. C can be either way.
West Route: Turnout A to West, turnout C to west leg; turnout B to Main,
East Route: Turnout B to East Route, Turnout C to East leg, Turnout A to Main.
This will allow a train to wait on the main while a train heads up the branchline.
Electronics are the most challenging part of the hobby for me. So a simple schematic with good labeling will go a long way toward sucessful implementation. Thanks