NCE DCC 4 Z power supplies and fuses

husafreak Dec 12, 2019

  1. husafreak

    husafreak TrainBoard Member

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    I have been getting advice on setting up my first DCC layout and so I have a NCE Power Cab. In an effort to reduce the possibility of damage to my loco's I will swap the NCE wall wart for a 12V one. I believe the factory power supply is rated at 2A, but I have Rokuhan wall warts that are 12V and 1A which may work if that amp is enough for the Powercab and Z loco's.
    I read a bit about placing a 12V 1157 auto tail light in one of the track wires coming from the Powercab to (hopefully) act as a fuse. But of course there is disagreement about what bulbs to use. If you are doing this with Z loco's what type of bulb are you using?
     
  2. rray

    rray Staff Member

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    Switching from 2A to 1A is not the problem. The bulb will solve the problem. What happenes in a short circuit situation, like when a wheel shorts the track, is the power cycles off, then on to check if still shorted. The 2A will heat the rails and wheels faster than 1A, but having the light bulb there to take the load is a better solution, because instead of heating up the wheel and rails, it heats the filiment in the lamp.

    Having 2A is better than 1A, because you can run more things like sound chips in passenger cars or freight head end cars, more locomotives, and accessory decoders. It's the short circuit safety you want to persue. So, 1156 or 1157 bulb? the 1156 has one filament, and the 1157 has 2. You can solder to both contacts on the bottom of an 1157 bulb in parallel and the current will go through both filaments, but the 1157 is a lower current bulb, at 1.6A 12V and the 1156 is 2A 12V.

    So the 1156 bulb needs 2A to light up, and that means if you put that bulb in series with a DCC track feeder, only in a short circuit situation will the bulb light up with your 2A power supply. It will take the heat, and your rails and wheels that are shorted will not heat up. You will see the light bulb flash for a fraction of a second every 1 or 2 seconds, each time the DCC system tries to turn the power back on.

    That said, I have not used DCC protection other than circuit breakers, and I have had locos pick the rqail points, short out, and melt down! I should have used am 1156 bulb in series, but I am too lazy as are most DCC users.

    Mark Gurries has a fantastic writeup here:
    https://sites.google.com/site/markg...-discussions/dcc-circuit-breakers/light-bulbs
     
    husafreak likes this.
  3. husafreak

    husafreak TrainBoard Member

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    Great info.
     
  4. SJ Z-man

    SJ Z-man TrainBoard Member

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    You do NOT want a 1A wall-wort, as each time you have a short, the power to the Power Cab is lost and it has to Power up again (a few seconds) but it won't start where it left off ! So, you have to Speed Increase again.
    The bulbs are sort of a help, but not perfect. You still will have current flowing and, since it is now limiting the short current, the Power Cab will not cut off the power. That means, if you are not watching our trains and it derails and shorts, you are still risking a heated axle.

    ALWAYS WATCH YOUR TRAINS.

    As I replied to this topic by PM request your for this info, I mentioned that there are HUNDEREDS of of us using the Power Cab As-Is.
    We except mortality and replacing an axle isn't that bad.
     
  5. husafreak

    husafreak TrainBoard Member

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    Ok great. And thank you for the time you took to educate me on DCC via those PM’s! You did mention 12V power supplies of 2A or more and light bulb fuses. Of course the internet is full of arguments about just which lightbulbs to use etc. But I didn’t want to be too much of a bother so I posted here. I’ll get a 2A wall wart and a 1156 bulb, I’ll watch my trains, and I’m not too worried if something does melt I’ll fix it.
     
  6. ZFRANK

    ZFRANK TrainBoard Member

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    I have a car rail light in series with track power, but my NCE power cab switches off faster than the bulb starts to light when running into wrong aligned points. So NCE short protection works pretty well.

    Verstuurd vanaf mijn ANE-LX1 met Tapatalk
     
    markm likes this.
  7. husafreak

    husafreak TrainBoard Member

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    In the end I purchased a DCC Specialties PSX-1, buzzer, and reset button. I elected to hardwire rather than to program it via CV's. So after soldering the components together and jumping the 1.27A cutoff I found it to be a great little device. To test it while running trains with my Powercab I shorted the track, trains stopped, buzzer came on, it was a forced short so no problem to solve, pressed the reset button and the trains went back to work. It is expensive but so are my little loco's. At least it works and works well. Since playing with DCC this year I have not had a short on the track, but if that buzzer ever comes on in actual practice I'll be glad it's there.
     
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