How the heck do I wire up Rohukan turnouts?

Heay Equipment Designer Oct 5, 2017

  1. Heay Equipment Designer

    Heay Equipment Designer TrainBoard Member

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    As I've been trying to understand DC, best analogy I can give it and relate to is a simple hydraulic system with a manifold to control fluid direction. DC Power source is the pump and reservoir, switch is the manifold with valves to control the direction of flow to a ram(s) or hydraulic motor(s). Manifold keeps the same direction of flow from reservoir thru the pump to the manifold and back to the reservoir at all times, otherwise the pump wont work. So the switch controls the current direction to the coil in the turnout like valves on a manifold controlling the direction of the ram or motor. I ended up using a spring loaded momentary center off switch which in a way acts just like the valve in the hydraulic manifold. Spring in switch prevents the "valve" from staying open in either direction.

    I'm using a zener diode to convert to DC and step down the 12 volt AC from the transformer to 6 volts DC. I was told at the electronics store that this is not a true form of DC because I'm only controlling the direction on one wire and this should not work... So I guess somehow I am defying the a laws of AC/DC because it works and works well. Here's a quick video of the turnouts using momentary center off switches.



    I realize I can still burn out the coils in the turnout if I'm not careful. So this is a short run fix. Just wanted to get everything working so I could show my 86 year old Dad a video of the test layout running. We started it together over the summer when I went to FL for a visit. I finally had some free time and I did all the wiring for the turnouts I'm using right now (minus the burnt one...) and track block sections on control board this weekend. He was heavily into N scale until the mid 80's. So he's tickled pink that I'm getting into Z scale. Now that everything works, he got to see it in a video all running and I know it put a big smile on his face, I can take my time and try to do these controllers using a capacitor.

    DSC05578.JPG DSC05609.JPG

    That all being said, I understand the basic principles of what a capacitor is and what it does even before I read the AZL forum on the turnouts. So I too was a bit confused by the schematic on the AZL forum (I would add a link from the AZL forum but I dont know if that's against the rules) that showed a copy of the KATO controller schematic. Even to my ignorant eyes, it seems to work in only one direction. The gentleman that was preforming all the experiments said it would work with a "SPDT instead of a DPDT switch".

    Drawing at the bottom left is an exact copy of the "KATO" controller posted on the AZ forum. The drawing on the upper left was the sales guy at the local electronics store translation of it. The drawing on the right is what he said is how I would wire what was on the schematic. But he was also scratching his head at this....

    IMG_008.jpg

    So I guess my question is, how did the guy on the AZL forum get this simple circuit to work and work with the Rohukan turnouts and with a SPDT switch?

    Also, whatever the final solution is, if I need "true DC" to make it work, I'm not against using and external DC power supply. I'd rather do that than try to build a converter which is light years above my head and abilities....
     
  2. Heay Equipment Designer

    Heay Equipment Designer TrainBoard Member

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    SYmpatico? I like it! If all else fails Trey, this might just be the ticket. Thanks.
     
  3. Heay Equipment Designer

    Heay Equipment Designer TrainBoard Member

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    Mark,

    one clue to where I got this circuit from. It was in a AZL forum you had commented a few times on in this subject back in July of this year if that wrings a bell. The gentleman that started the thread and was making this controller goes by "alberich".
     
  4. JuergenT

    JuergenT TrainBoard Member

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    Hi Jon

    to switch the Rokuhan Turnouts you can use these small elektronic
    [​IMG]

    it works in my layout "Flaggstone East Terminal" perfect.
    I use a toggle switch with 2 contacts (to move 2 turnouts together).
    Power is 12V DC (14V)
     
  5. markm

    markm TrainBoard Supporter

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    Don,

    The circuit from AZL was contributed by Jeff who is far more familiar with what's happening in other scales than I. You may have noticed that I backed away from that thread as it started as a keep it simple/idiot-proof discussion and that circuit has some risks as I described above. Personally, I want to build an idiot-proof control panel with indicator lighting so I started with the Rokuhan C0002 unit.

    I've also been using this simple circuit for experimentation using the DPDT switch. From Garth's comment, it really shouldn't work for me as at 12VDC it isn't supplying 20mA. If you start with the R1 resistor and it doesn't work, add the second R2 resistor across it and that should supply the current you need.
    don.jpg

    There is an error in labeling: the Black-white is the wire from the turnout to the resistor.

    This may have issues if you hold the switch in one position, although Garth's comment would suggest otherwise. BTW: Garth is the real expert on Rokuhan products on this side of the Pacific.

    Hope this helps.

    Garth,
    You mentioned a website that had technical specs for the turnout. Can you post the link? We should be able to find it in one of the internet archive sites.
     
  6. Heay Equipment Designer

    Heay Equipment Designer TrainBoard Member

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    When starting this thread, I understood one of the basic functions of the capacitor, it charges up and stores power. What I did not know was that it also lets the same amount of current pass thru that the capacitor can hold as it charges. So it will only let 1500uF pass thru the turnout. After learning this the original circuit finally made sense to me as I have drawn it up in the pic. Capacitor only lets 1500uF pass thru the turnout to throw the turnout when the on on switch is "on" with power flowing into the capacitor (A). Capacitor fills up, power is cut to the turnout and the capacitor is holding 1500uF. Turn the on on switch the other way (B), it unloads the capacitor in the opposite direction and throws the turnout in the opposite direction. In Theory its a really simple solution...

    So jump forward a month later to now after understanding how this circuit works or thinking I understand how it works, I finally got a day off to travel to my machine shop and try to replicate this circuit on the layout. Got what you see in the pic at my local electronics shack and wired it up. It worked beautifully and flawlessly in both directions! Until I wired the second turnout.... Then I noticed a really high but very faint pitch sound after the capacitor charged up and threw the turnout. But the noise went away after I let the capacitor discharge to throw the turnout the other way... Turns out, the buzz from my shop lights drown out the high pitch sound from the first turnout I wired. Turned off the lights and then I could hear it being replicated in both turnouts... Fortunately I did not have the regulated 6 volt DC power source on for very long and neither turnout was warm and both still function as they should. Went back to the electronics shack and the guy that was helping me thought this might be a problem, leaky capacitors... So I'm baffled as to how the gentleman got this circuit to work without having the same problem I had with just using this circuit. I'll post my results on his forum and see what he did to avoid the problems I'm having with it.

    For now I'll stick with the momentary double throw spring loaded center off switches since this is just a learning/experimenting control board and layout for me. I do like how the on on switch lets you know the turnout direction. So next go around I'll probably go with Trey's solution with the OEM switches that will easily fit on my style of control board. Unless there is still some missing link I'm just overlooking with this circuit....


    IMG_010.jpg
     
  7. Pig Gap

    Pig Gap TrainBoard Member

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    I am using circuit designed by George Stilwell Jr for KATO N-scale switches to power my Rokuhan switches. Mr Stilwell calls it a BCD, it uses a SPDT switch and also powers a Bicolor LED (red/green) for switch direction indications. If you are handy with a soldering iron, you may be able to more information on it in N-Gauge discussions. Because both Rokuhan and KATO us the same basic design for switches, any controller for KATO should work for Rokuhan.
     

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