To DCC or not to DCC there are so many questions

Discussion in 'DCC Control' started by Graeme, Feb 1, 2019.

  1. Graeme

    Graeme Full Member

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    Thanks Keith seeing as I do not have to switch points via DCC and I have a CDU I will most likely go back to the method I used on my old DC layout which will be a lot less hassle for me.
    The way I will do it; is to wire the +ve of my CDU to the centre contact of a SPDT switch with the 2 outputs going to either side of a solenoid on the motor and the other side of each solenoid will be joined and the common wire from the CDU connected to them.
    There will be a momentary switch in series in the +ve line before the SPDT switch so that depending on which leg I wanted to run through I just move the switch and "fire" the CDU with the momentary.
    The position of the SPDT will show which leg was set (Up=straight through, Down=curve) to add to this I will glue a microswitch to the point motor with one way for straight (Normally Closed) and the other for curve (Normally Open) this switch will turn on LEDs on a schematic panel to showed which leg is switched/set.
    I could also use this switch to light signal lights.
    Hopefully that does not confuse to many people, I can do a picture if needed.

    Edit;
    Did a drawing which explains it better.
    The +12V is the output of the CDU.

    Points Wiring Diagram.jpg
     
    Last edited: Feb 14, 2020
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  2. Graeme

    Graeme Full Member

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    Here is the next silly question in what will most likely be a series of them.
    I haven NCE a PowerCab that came with a 1.36A supply but the power cab manual quotes a 2A capacity.
    NCE describe the Power cab as "The Power Cab is a self-contained DCC system in one package. It is a Cab / Throttle, it is a DCC Command Station, and it is a Booster. All three in one package."
    Am I right in my reading of this that it has a built in booster to take it to 2 A and thus allow me to run up to the 4 locos they quote?
    I will not be running my points off DCC but off a CDU as in the post above.
     
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  3. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    Morning Graeme,

    what you have to think is max current draw with the ampage. Not the consistent - I’m not sure where you have the limit of 4 locos? You can run as many as you want, but, with things like sound and some motors, there will be a bigger draw than others - my ZTC controller has a led bar light which shows current draw, and I don’t think I’ve ever come close to 2.5a draw even with 5 sound decoders running.

    If your still worried, change the power supply.

    but I bet you still have a 13amp fuse in the plug! o_O
     
  4. Graeme

    Graeme Full Member

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    There is no fuse in the plug, plugs do not have a built in fuse in Australia not that I have ever seen. The power supply is a plug pack type, what they call "wall wart" in the US

    The 4 locos limit come from NCE who use a rule of thumb that a HO loco draws 0.5A so they quote 4 locos for 2A.

    I am reading that this thing has a built in booster to take it up to 2A just trying to confirm this.
     
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  5. bobcom52

    bobcom52 Full Member

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    The NCE Powercab is a combined throttle, command station and circa 2A booster. The booster is what takes the low level digital signals and converts them to the higher bipolar voltage that supplies the track. If I remember correctly the NCE documentation that comes with the Powercab is quite good and tells you the basics of the system and how to use it. If you did not get the manual with your gift it is freely available off the NCE website as a download. Worth reading first.
    Unlike Digitrax and Lenz the NCE system does not allow the running of one dc consist using address zero so if you want to be able to still run a dc loco at times you disconnect the wires from the NCE to the track and reconnect a dc powerpack. Connecting both at the same time will most likely see some expensive smoke rising! If you are planning on doing this on a regular basis then installing a double pole changeover switch (dpdt) would prove to be more convenient. This is contingent on you not powering the frogs with a 'juicer' and not using the Powercab handset to throw points.
    The Powercab is versatile unit, very useful for a layout with up to two operators as it comes. If it has not come with your package I suggest purchasing a CP6 fuse box and feeding your layout through at least one of the fuses. I remember when helping a friend install one of these on his layout, I put a tail light globe in the track feed to limit current draw on a s/c as he did not have a CP6 ( if it was even available at the time?) .
    Operation of decoder equipped locos on dc requires the function be turned on in CV29. They require the dc powerpack to be turned up part way before the decoder has enough voltage to run so not ideal if trying to double head with a dc loco but OK otherwise for non sound decoders. Also not all dc powerpacks are suitable for running a decoder equipped loco as they have too high an AC content confusing the decoder and with some combinations letting the smoke out of the decoder.
    Hope this explains some basics.
    DCC is great if you have use for its ability to run trains without sectioning and /or require sound or some of its other unique advantages. For others it is probably not needed.
    cheers
    Bob
     
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  6. Graeme

    Graeme Full Member

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    Next silly question of the rank is feeder wiring; Is there a convention as to which rail the +ve and -ve are attached eg +ve to front rail or to the rear rail as viewed from front of layout?
    For the temporary DC hookup the +ve is the rear rail (furthest from the operator).
     
  7. Sol

    Sol Full Member

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  8. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    As above from Sol,
    But, i do tend to keep to an Old DC theme as it still works the same. Red and Black go to track.. and Black to back (so closest rail is always red) providing tour stood inside the layout.
     
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  9. Graeme

    Graeme Full Member

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    Thanks for that.
    I am using 1mm diameter wire would that size be OK for a bus wire and feeders?
    If not OK for a bus I have enough to run 2 in parallel.
     
  10. Kimbo

    Kimbo Staff Member Moderator

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    Hi Graeme,

    I use jaycar for my wire.
    Droppers use :-

    https://www.jaycar.com.au/light-duty-hook-up-wire-pack-8-colours/p/WH3009

    $5.50 per roll, so I normally buy red, black and green for frog wires.
    ( as Andy has said I always use the black - back , red closest to yourule)


    Bus wire :- pre tinned, makes soldering the droppers to the bus a very easy task. At $4.40 ish a meter not cheap for a large layout, but I’ve never had a problem using it on either short 2-5m boards or long outdoor layouts

    https://www.jaycar.com.au/25a-2-core-tinned-dc-power-cable-sold-per-metre/p/WH3087


    Kim
     
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  11. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    Sounds a bit thin for a bus wire. Is it single strand?
     
  12. Graeme

    Graeme Full Member

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    Multi stranded wire.
    If I run 2 in parallel that should be OK yes?.
    The reason I want to use it because I have miles of it.
    I plan to run no more than 4 train max, because that is all I have I will probably run only 1 or 2 at a time.
     
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  13. Gary

    Gary Wants more time for modelling.... Staff Member Administrator

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  14. Chatty

    Chatty Full Member

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    It isn't so much the number of trains you are running but it's the wire capacity to react in case of a short.

    In the case of my Digitrax system, it has the capacity to supply 6 amps. In this case, the wiring has to be able to handle that current load and it is important in case of a short. So, if the wiring only has the capacity to say handle 4 amps then in the case of a short the current limiter will not react so if a wagon or a loco is the case of the short it could be cheerfully sucking up 60 watts of power which is enough to melt some wheels. Don't ask how I know.

    Digitrax recommends the coin test. Drop a coin, 50 cent coins work really well, and if the command station shuts down then it has passed the wiring test.

    So just to reiterate, it is not so much about the trains or accessories you are running but the capacity to handle a short. In the days of DC many controllers only supplied 1 amp to the track it wasn't so much of an issue but when a device can supply 6 amps it is much more of an issue.

    Kind regards

    Geoff
     
  15. Graeme

    Graeme Full Member

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    The DCC controller I am going to use is only capable delivering 2 Amps.
    I used the wire I have to wire a DC layout so maybe DCC is not for me, all my locos are not chipped so I may save money by going DC and selling the DCC controllers.
     
  16. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    I've just checked, 1mm wire should be OK so don't worry ((Gaugemaster are selling 0.2mm as layout wire.) So don't give up on DCC yet Graeme
     
  17. Chatty

    Chatty Full Member

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    Agreed. Once you have it up and running you will not wish to return to DC; correct Sol?

    Kind regards

    Geoff
     
    Last edited: Mar 13, 2020
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  18. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    Do you mean you won’t want to go back to DC? :avatar::avatar:
     
  19. Chatty

    Chatty Full Member

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    Thank you, Andy.

    Would you believe I retyped 3 times and I still buggered it up. My mind is elsewhere.

    I came onto the forum for a bit of light relief.
     
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  20. Sol

    Sol Full Member

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    Agreed Chatty , can't go back , spent too much $ on DCC equipment & I/we couldn't operate the D&S the same way under DC.
     
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