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Resistor wheel sets with DCC

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PED
  • Member since
    April 2016
  • 571 posts
Posted by PED on Friday, May 18, 2018 7:49 AM

Makes sense. I cannot tell what resistor it has nor how it was done. The whole setup is covered with paint. Sounds like a botched job to me. I do not need a resister wheel set so I will probably repace the truck with a stock setup.

Paul D

N scale Washita and Santa Fe Railroad
Southern Oklahoma circa late 70's

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Friday, May 18, 2018 6:14 AM

 A resistor wheelset is needed in DCC for the same purpoase as DC, to cause some current flow for unpowered cars so they can be detected by block detectors. It's actually easier with DCC since there is always power in the rails at a constant voltage. 

 This should not cause a short - you may have had a bad wheelset, but on my cars I use 2 resistor axles out of 4, each with a 10K resistor. That's 1.5mA per axle - not anywhere close to a short. 500 cars on the layout like this would still only be 1.5 amps, still hardly a short.

 We easily have hundreds of cars with resistor wheels on the club layout, but that's a big layout with 4 boosters plus the command station, and there are no issues with the resistor wheelsets. I suspect your problem was someone tried to make their own (I do for HO, but it's not terribly difficult. I don't know that I would DIY for N scale) and either blobbed solder or the conductive paint over the resistor, making it a short.

                              --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    December 2015
  • From: Shenandoah Valley
  • 9,094 posts
Posted by BigDaddy on Thursday, May 17, 2018 8:58 PM

PED
are resistor axles also used on DCC layouts? How? Why?

Yes, same reason.

https://ncedcc.zendesk.com/hc/en-us/articles/203218359-Making-resistor-wheel-sets

The block detectors need that extra resisitance.   5 milliamps, mentioned in that reference, should not cause breakers to trip.  Of course we don't know who installed what resistor.  If you can see the color stripes you can figure out what size resistor it is.

 

Henry

COB Potomac & Northern

Shenandoah Valley

PED
  • Member since
    April 2016
  • 571 posts
Resistor wheel sets with DCC
Posted by PED on Thursday, May 17, 2018 8:10 PM

I put a consist of N scale Kato passenger cars (some new and some used) on my layout today and it created havoc with my DCC layout. After checking all the cars, I discovered that one of the used ones apparently had a resistor wheel set (I think) on it. The axle has something on it that was not stock. It was causing my system to read that as a short about every three feet and trip the breakers for about 1 second then the train would move about another three feet and repeat the process.

 I know people use resistor axles on DC layouts to determine occupancy but are resistor axles also used on DCC layouts? How? Why? Obviously it was creating a problem on my layout (Digitrax with circuit breakers on the PM42).

Paul D

N scale Washita and Santa Fe Railroad
Southern Oklahoma circa late 70's

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