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Help !! Rokuhan burning switches

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  • tpalex
    Hello all, few minutes ago something really weird happened on my layout. Firstly i want to say that last year a Rokuhan switch had a sudden bright spark and
    Message 1 of 9 , Apr 14, 2014
      Hello all,

      few minutes ago something really weird happened on my layout.

      Firstly i want to say that last year a Rokuhan switch had a sudden
      bright spark and smoked when a locomotive had a shortcut on it
      (direction not set properly). I thought it was an exception since I have
      many of them and locos blocked in this way this happens quite often.

      This evening the following occurred.

      This time i was using a DCC loco (AZL GP-38) it turned left on a Rokuhan
      turnout (lets' call it sw.1) passed another turnout (MTL sw.2) and
      started to manoeuvre backward to take few cars. It reached a 3rd turnout
      (Rokuhan sw.3) and stopped there supposedly for a shortcut. At that
      point the loco did not move anymore.
      All that yard section is powered through the way out of sw.1 and it took
      me some time to realize that that switch on the mainline (sw.1) was not
      powering the way out anymore.
      Loco arriving on the mainline now stopped just turning left.

      I replaced that switch with another one and repeated the process, Loco
      went out of mainline at sw.1 crossed sw.2 and started to go back toward
      sw.3. This time the loco stopped on sw.2 and guess what... again no
      power on the yard and also the new sw.1 seems failing in the same way!!!

      So balance of the evening is 2 rokuhan left switches to drop.

      Anyone experienced something like this?
      What's your opinion? Can it be related to the DCC power?
      What is there inside the Rokuhan switch to fail in this way? No burn, no
      smoke, no sound...

      Any help is greatly appreciated!!

      Alex
    • garthah
      I have one question, since you are using DCC what configuration are the turnouts in power routing or non power routing? From your description of the took me
      Message 2 of 9 , Apr 14, 2014
        I have one question, since you are using DCC what configuration are the turnouts in power routing or non power routing? From your description of the  "took 
        me some time to realize that that switch on the mainline (sw.1) was not 
        powering the way out anymore."  this sounds to me that they maybe in power routing mode and not the non power routing mode intended for DCC operations.. The second question is what it the power rating of your DCC system? Is it 1.5, 2 , 3 or 5 amps.  A short circuit on a 5 amps system produces enough power to light a 75 watt lamp, that is allot of heat, while at 2 amps only enough to light a 25 watt night light, still hot but might not burn your fingers immediately. If I were using a 5 amp system I would be using a fro juicer to control polarity at the frog of my turnouts. .I am using DCC also but only 1.5 amps at 12 volts AC, and so fare I have not had any problems with burnt turnouts and they are all non power routing. I have 6 turnouts a cross over and 2 double slip turnouts and on one of my yard tracks I have an isolated section that operates as my program track.  So far I have not lost a single turnout.  It may be because I have a 1 Watt lamp in series with my track power and if I have a track short it lights up to tell me I have a problem and limits the current and hence the heat at the point where the short is occurring.

        regards Garth


        ---In z_scale@yahoogroups.com, <tpalex@...> wrote :

        Hello all,

        few minutes ago something really weird happened on my layout.

        Firstly i want to say that last year a Rokuhan switch had a sudden
        bright spark and smoked when a locomotive had a shortcut on it
        (direction not set properly). I thought it was an exception since I have
        many of them and locos blocked in this way this happens quite often.

        This evening the following occurred.

        This time i was using a DCC loco (AZL GP-38) it turned left on a Rokuhan
        turnout (lets' call it sw.1) passed another turnout (MTL sw.2) and
        started to manoeuvre backward to take few cars. It reached a 3rd turnout
        (Rokuhan sw.3) and stopped there supposedly for a shortcut. At that
        point the loco did not move anymore.
        All that yard section is powered through the way out of sw.1 and it took
        me some time to realize that that switch on the mainline (sw.1) was not
        powering the way out anymore.
        Loco arriving on the mainline now stopped just turning left.

        I replaced that switch with another one and repeated the process, Loco
        went out of mainline at sw.1 crossed sw.2 and started to go back toward
        sw.3. This time the loco stopped on sw.2 and guess what... again no
        power on the yard and also the new sw.1 seems failing in the same way!!!

        So balance of the evening is 2 rokuhan left switches to drop.

        Anyone experienced something like this?
        What's your opinion? Can it be related to the DCC power?
        What is there inside the Rokuhan switch to fail in this way? No burn, no
        smoke, no sound...

        Any help is greatly appreciated!!

        Alex
      • trainssd
        Yes, they won t take high currents very well. Most common situation is where the switch is not thrown completely, i.e. the internal power contacts are not in
        Message 3 of 9 , Apr 14, 2014
          Yes, they won't take high currents very well.
          Most common situation is where the switch is not thrown completely, i.e. the internal power contacts are not in "sync" with the actual position of the points.
          Then when a loco comes through, and forces the connection between one of the stock rails and the point rails (closure rail?) you have a short.
          My experience is that then the internal contacts burn out.
          We've seen this in the BFY (big freaking yard) where the switch only has power through it when the rail actually makes contact... and of course this is not good, that's why there are internal power contacts.

          Note that this has nothing to do whatsoever with power routing, the short occurs when the loco or car is "in" the switch.

          This might not be your exact situation, but I have experienced the "burning out" of the internal power contacts, meant to power the moving part of the switch.

          In parting, if you have a large layout, 5 amps is a normal supply.

          Greg


          --In z_scale@yahoogroups.com, <tpalex@...> wrote :

          Hello all,

          few minutes ago something really weird happened on my layout.

          Firstly i want to say that last year a Rokuhan switch had a sudden
          bright spark and smoked when a locomotive had a shortcut on it
          (direction not set properly). I thought it was an exception since I have
          many of them and locos blocked in this way this happens quite often.

          This evening the following occurred.

          This time i was using a DCC loco (AZL GP-38) it turned left on a Rokuhan
          turnout (lets' call it sw.1) passed another turnout (MTL sw.2) and
          started to manoeuvre backward to take few cars. It reached a 3rd turnout
          (Rokuhan sw.3) and stopped there supposedly for a shortcut. At that
          point the loco did not move anymore.
          All that yard section is powered through the way out of sw.1 and it took
          me some time to realize that that switch on the mainline (sw.1) was not
          powering the way out anymore.
          Loco arriving on the mainline now stopped just turning left.

          I replaced that switch with another one and repeated the process, Loco
          went out of mainline at sw.1 crossed sw.2 and started to go back toward
          sw.3. This time the loco stopped on sw.2 and guess what... again no
          power on the yard and also the new sw.1 seems failing in the same way!!!

          So balance of the evening is 2 rokuhan left switches to drop.

          Anyone experienced something like this?
          What's your opinion? Can it be related to the DCC power?
          What is there inside the Rokuhan switch to fail in this way? No burn, no
          smoke, no sound...

          Any help is greatly appreciated!!

          Alex
        • garthah
          Greg, I guess the big question is 5 amps really necessary to power the BFY? I did my DCC introduction on a big HO club layout and I know that, 5 amp power
          Message 4 of 9 , Apr 15, 2014
            Greg, I guess the big question is 5 amps really necessary to power the BFY? I did my DCC introduction on a big HO club layout and I know that, 5 amp power districts is the norm in that realm, but this isn't HO it is Z.  It certainly isn't on my home layout which is 4  by 12 L shaped and only 2 ft wide. and I usually have 6 locos on the track.  and operate as many as 4 at a time on 2 amps. at 12vac.  

            What can be done to control points so that they are set for direction of travel so you are not running against the set position of the points? I know from my experience going from block to DCC I tended to forget about turnouts and turnout positions, as the dispatcher was controlling that In HO not so not much a big deal with hand laid  track and turnouts and tortoises and Frog Juicers and the addition of ground signals, at each turnout, but coming down to N and Z it becomes more of a problem as this infrastructure, and sophistication is not present, in many cases. I also use a current limiting lamp(one amp) in my track supply, in each power district, in addition to the circuit breaker in the power supply.

            regards Garth
          • tpalex
            Thanks Garth and Greg, yes I am using power routing, I intended to use the layout in DCC and non-DCC mode, not at the same time obviously. For DCC I use
            Message 5 of 9 , Apr 15, 2014

              Thanks Garth and Greg,

              yes I am using power routing, I intended to use the layout in DCC and non-DCC mode, not at the same time obviously.
              For DCC I use Digitrax DCS51 that should be 3A max, I was afraid to burn the locos not the switches :( really a surprise.
              The weird thing is that in this case the switch burns when the loco is not on it and actually was engaging
              the other switches in the straight direction and position correctly set. Probably there was a shortcut anyway but it's a scenario completely unavoidable... this makes DCC not feasible in my layout where I decided to not use wiring or other devices more complex than the trafo or the DCC controller :(

              Interesting the light bulb suggestion Garth, may you detail how to connect it to have this protection effect?
              Maybe i can give it a try at risk to sacrifice other turnouts.

              I will try to contact Rokuhan to have their comment. They could do something to avoid this problem
              in the future maybe.
              They say nothing in the instruction manuals about this risk, not even in the part describing how a shortcut can happen.

              BR,

              Alex




              On 15/04/2014 02:52, garth.a.hamilton@... wrote:
               

              I have one question, since you are using DCC what configuration are the turnouts in power routing or non power routing? From your description of the  "took 
              me some time to realize that that switch on the mainline (sw.1) was not 
              powering the way out anymore."  this sounds to me that they maybe in power routing mode and not the non power routing mode intended for DCC operations.. The second question is what it the power rating of your DCC system? Is it 1.5, 2 , 3 or 5 amps.  A short circuit on a 5 amps system produces enough power to light a 75 watt lamp, that is allot of heat, while at 2 amps only enough to light a 25 watt night light, still hot but might not burn your fingers immediately. If I were using a 5 amp system I would be using a fro juicer to control polarity at the frog of my turnouts. .I am using DCC also but only 1.5 amps at 12 volts AC, and so fare I have not had any problems with burnt turnouts and they are all non power routing. I have 6 turnouts a cross over and 2 double slip turnouts and on one of my yard tracks I have an isolated section that operates as my program track.  So far I have not lost a single turnout.  It may be because I have a 1 Watt lamp in series with my track power and if I have a track short it lights up to tell me I have a problem and limits the current and hence the heat at the point where the short is occurring.


              regards Garth


              ---In z_scale@yahoogroups.com, <tpalex@...> wrote :

              Hello all,

              few minutes ago something really weird happened on my layout.

              Firstly i want to say that last year a Rokuhan switch had a sudden
              bright spark and smoked when a locomotive had a shortcut on it
              (direction not set properly). I thought it was an exception since I have
              many of them and locos blocked in this way this happens quite often.

              This evening the following occurred.

              This time i was using a DCC loco (AZL GP-38) it turned left on a Rokuhan
              turnout (lets' call it sw.1) passed another turnout (MTL sw.2) and
              started to manoeuvre backward to take few cars. It reached a 3rd turnout
              (Rokuhan sw.3) and stopped there supposedly for a shortcut. At that
              point the loco did not move anymore.
              All that yard section is powered through the way out of sw.1 and it took
              me some time to realize that that switch on the mainline (sw.1) was not
              powering the way out anymore.
              Loco arriving on the mainline now stopped just turning left.

              I replaced that switch with another one and repeated the process, Loco
              went out of mainline at sw.1 crossed sw.2 and started to go back toward
              sw.3. This time the loco stopped on sw.2 and guess what... again no
              power on the yard and also the new sw.1 seems failing in the same way!!!

              So balance of the evening is 2 rokuhan left switches to drop.

              Anyone experienced something like this?
              What's your opinion? Can it be related to the DCC power?
              What is there inside the Rokuhan switch to fail in this way? No burn, no
              smoke, no sound...

              Any help is greatly appreciated!!

              Alex

            • garthah
              Alex; I use the lamps from NCE but that is not necessary. If you are using a 3 amp 15 volt DCC system then a 15 watt lamp , from any source, will hold short
              Message 6 of 9 , Apr 15, 2014
                Alex;  I use the lamps from NCE but that is not necessary. If you are using a 3 amp 15 volt DCC system then a 15 watt lamp , from any source,  will hold short circuit current to one amp max. and you connect the lamp so the filament is in one lead of the track power from your DCC system to the track. So the filament of the lamp is essentially part of the one lead to the track. A short across the track will light the lamp and since the filament is a resistor it will only flow the 1 amp of current max required to light the lamp. I put the lamp up above the layout on a dowel so it is easy to spot and I have one for each power district. 

                regards Garth
              • trainssd
                A few comments: Garth if you want to discuss the DCC current requirements of a layout, or the BFY let s take the discussion onto another thread. (hint,
                Message 7 of 9 , Apr 15, 2014
                  A few comments:
                  Garth if you want to discuss the DCC current requirements of a layout, or the BFY let's take the discussion onto another thread. (hint, locomotives standing still draw current too, and sound units, and lighted cars).

                  The light bulb across the tracks to limit current to 1 amp, still allows 1 amp to flow through the short, which can cause damage too.

                  The solution is to not have the shorts, ha ha. Seriously, you want to have electronic circuit breakers that are fast acting, not a bunch of light bulbs that take time to light up. DC operation can handle some things, but DCC and fragile turnout contacts are not so forgiving.

                  Also, I do believe that a lamp in the DCC power path might cause some command problems, it will most likely have some effect on the DCC waveform.

                  Greg
                • Alan Cox
                  On 15 Apr 2014 20:04:42 -0700 ... So you split it into more sections with smaller power draw. ... Can you split the wiring on the Rokuhan and just wire the
                  Message 8 of 9 , Apr 16, 2014
                    On 15 Apr 2014 20:04:42 -0700
                    <greg@...> wrote:

                    > A few comments:
                    > Garth if you want to discuss the DCC current requirements of a layout, or the BFY let's take the discussion onto another thread. (hint, locomotives standing still draw current too, and sound units, and lighted cars).

                    So you split it into more sections with smaller power draw.

                    > The solution is to not have the shorts, ha ha. Seriously, you want to have electronic circuit breakers that are fast acting, not a bunch of light bulbs that take time to light up. DC operation can handle some things, but DCC and fragile turnout contacts are not so forgiving.

                    Can you split the wiring on the Rokuhan and just wire the blades to the
                    frog then use a frog juicer instead of the contacts ?

                    > Also, I do believe that a lamp in the DCC power path might cause some command problems, it will most likely have some effect on the DCC waveform.

                    Shouldn't do to any degree that matters, and it would only have a
                    material effect if it was shorted already - when you don't care.

                    Still the wrong technology given you can get fast acting section breakers.

                    Alan
                  • trainssd
                    Yes, the best practice in DCC is to break your mainline / layout int smaller power districts, each with it s own electronic circuit breaker, and clearly, set
                    Message 9 of 9 , Apr 16, 2014
                      Yes, the best practice in DCC is to break your mainline / layout int smaller power districts, each with it's own electronic circuit breaker, and clearly, set to a lower amp trip point. This is common DCC practice for all scales.

                      Using a frog juicer to power the points is expensive, but yes, a very good solution, I do this in my G scale.

                      How much will a light bulb in series affect your DCC operation, you be the judge. I have an electronics background and a nice scope to see the actual situation, and also a protocol checker that can indicate the number of errors in DCC packets. I said "I believe a lamp might cause some problems".... OK clearly the caveats did not help.... I've seen many DCC situations, and the DCC waveform is much worse than many people realize... the decoders are getting better at picking out the right signal, but I don't design my stuff to just work, but to be 100% reliable so I spend my time enjoying trains not debugging my electronics. There are still decoders very touchy over the DCC waveform, like TCS decoders, so you'd have to hold a gun to my head to have me add a light bulb to my layout... but maybe it would work for you. Each to his own, but when I give advice, I give the best advice I can, that will work as best as possible.

                      Regards, Greg
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