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  • Topic: DCC++ More Power

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    • January 29, 2019 10:22 PM EST
      • Branchport, NY
         
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      DCC++ More Power

      Some people didn't want DCC++ because it didn't have enough power.

      GEOFF has a 15AMP motor shield solution.

      15AMP Motor Shield

      I would think this would handle most stuff without the extra circuit building

      required for the Trainelectronics solution.

      There is no short circuit protection in this shield. Fuses or something else should be added.

      Tom

       

      This post was edited by Tom Stephens at January 29, 2019 10:23 PM EST
    • January 30, 2019 10:50 AM EST
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      When you start using higher power, you really need something more sophisticated than a fuse.

       

      This is the danger in high current solutions, you can get a short in a loco that draws 5 amps and will overheat the wires and other components in the loco, melt plastic, and yet you are only drawing 5 amps and will not trip a breaker or blow a fuse.

       

      I would recommend a "smart" DCC breaker. I have a 20 amp system that had several smart algorithms and many settings for short circuit detection.

       

      Not being negative, but at higher current levels you need something more sophisticated if you want a 15 amp power district.

       

      Greg

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    • January 30, 2019 9:20 PM EST
      • Branchport, NY
         
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      Poor Installation

      Greg Elmassian said:

      When you start using higher power, you really need something more sophisticated than a fuse.

       The fuse was just a generic term saying that you need something to protect the supply as it doesn't have any protection built in.

      This is the danger in high current solutions, you can get a short in a loco that draws 5 amps and will overheat the wires and other components in the loco, melt plastic, and yet you are only drawing 5 amps and will not trip a breaker or blow a fuse.

       If this happens - you have a poor installation. Wires need to be protected against any current that exceeds the wire's current carrying capability. You wouldn't hook an outlet in you're house to a 200AMP panel with 14gauge wire without a circuit breaker in between would you? The circuit breaker is there to protect the wires and not whatever you plug into the outlet. The locomotive should have something to protect against your hypothetical 5AMP short.

      I would recommend a "smart" DCC breaker. I have a 20 amp system that had several smart algorithms and many settings for short circuit detection.

      Does it know the difference between two locomotives drawing 2.5AMPS each and one locomotive with a 5AMP short?

      Not being negative, but at higher current levels you need something more sophisticated if you want a 15 amp power district.

      What you have described can happen with a supply much smaller than 15AMPS if you don't have any protection in the locomotive.

      Protecting a power district and protecting wires in a locomotive are two different problems.

       This discussion could continue with many different opinions, but it really boils down to protecting the wiring. People usually think the "fuse" is there to protect the device hooked to the wires. The "fuse" is there to protect the wires. If the device needs protection, it should have its' own protection built in.

      Tom

       

      Greg

       

    • January 31, 2019 12:24 PM EST
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      Sorry Tom, have to pretty much disagree with you on several counts.

       

      On the fuses.... if you wanted to say something more, then please say it... the "something else" in my opinion does not go anywhere near communicating what is needed, and I don't think you can find a sophisticated current sensing overload protection circuit to add to this unit, at any cost. So, let me go further and say in my opinion, this is an unacceptable product without it having a more sophisticated overload/short protection circuit added, and people who think you can safely "strap on" 15 amps should be warned.

       

      Poor installation? You are addressing only part of the understanding here... the "kindergarten" part of understanding power delivery to the rails and ultimately the loco is something already assumed, since I can tell you have advanced understanding of DCC and we are in the DCC forum. I was very specific about the LOCOwiring which is often not properly considered.

       

      You quote the part where I indicate "overheat the wires and other components in the loco"  but you fail to address it, with other than "The locomotive should have something to protect against your hypothetical 5AMP short"

       

      THAT IS THE ISSUE! Most people cannot rewire their locos to handle a 5 amp short from a derailment, the power pickup components from the wheels, brush holders, the gauge of the wires to the circuit board and the circuit board traces themselves... I've even seen melted plastic driver wheel centers on MTH locos from such a short.

       

      And YES this can occur with less than 15 amps, which was my point too... but 15 amps makes this even MORE of a problem without an equally more sophisticated short circuit protection system.

       

      I am making the assumption that the average user CANNOT revise his ENTIRE fleet of locos to withstand a 15 amp short circuit caused by a derailment, i.e. the short circuit is going between the wheels of the locos.

       

      It's easy for you to say " If the device needs protection, it should have its' own protection built in"

       

      But have YOU done this to all your locos? Can I apply 15 amps to all of your locos, for example a short from left side tender wheels to left side drivers? I'll eat my hat if you say yes.

       

      So, let's give advice that is safe to people who know less than you, at least warnings... I run 20 amps, and before that I ran a 10 amp NCE that would put out 20 for a while... I've melted boards and wires and pickups and not tripped "fuses".... I learned the hard way.

       

      There's a reason I have a microprocessor monitoring and controlling the output power in my system, and it's vitally important in the high current ranges.

       

      Greg

      This post was edited by Greg Elmassian at January 31, 2019 1:31 PM EST
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    • January 31, 2019 3:24 PM EST
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      I have one of these things on the way, and an NCE EB1 for the output side.  Should be interesting to experiment with.

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    • January 31, 2019 6:33 PM EST
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      Pretty sure that NCE uses PIC processors, and they do indeed analyze the amount of the short and length of time.

       

      If I showed you the criteria and the settings on the Zimo protection "circuit" (which is really a computer algorithm) it would blow your mind... of course so would the price tag.

       

      I've really experienced the differences between fuses, breakers and something that is indeed "analyzed".

       

      Greg

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      Be sure­ to visit ­my site, l­ots of tec­hnical tip­s and modi­fications,­ and you c­an search ­for topics­ and key w­ords.


      ­Click HERE for Greg­'s web sit­e
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