I have an MRC DCC system with MRC booster and MRC auto reverse modules. My layout has 3 power districts. It is a point to point and with each end on the lower level. The lower level is just 2 loops that reverse on themselves. Both loops are part of the same power district, Red.
I keep getting a short that causes the auto reverse modules to trip without end-the only way to reset them is to disconnect the feeders. I removed ever feed but one for each district-each loop has a feeder (both Red) and each of the other 2 districts (Green and Blue) have just one pair if feeders. This to keep it simple and remove any potential for other sources of trouble.
So, can anyone help me with how to stop this never ending loop of auto reverse module shorts. It has happened with a derail, with a loco with the power district, but I don't think when there is nothing on the track. I run the 3 districts through a 4 circuit panel. There are no crossed wire, loose connections, I have been over everything. It ran great for a while today and then I could not get them to reset without removing the both pair of feeders and them reconnecting. Only that stopped it.
I am lost so, I am not super experienced with DCC, hoping there is an adjustment via DCC that can help this.
Many thanks in advance
Captwilb
Any
I think we need a bit more info regarding how you wired your reversing loops before we can help you. If i were to build a similar track plan, I would insulate both rails at each end of each reversing loop (four rail gaps for each loop). I would then connect one reversing module between the main DCC bus and one reversing loop. I would connect another reversing module between the main DCC bus and the other reversing loop. Is this what you have done?
Hornblower
As Hornblower wrote, both ends of both loops must have both rails insulated so the loops are totally isolated electrically from the rest of the layout. If you didn't use insulated rail joiners at these 4 locations, that could be your problem.
when the short happens, both the reverse modules start clinking and turning off the system does not help-when turning it back on the short is still there. only disconnecting the feeders physically stops the short. that is the part I do not understand
How long are the reverse loops, and how long are the trains you are running through them? Do you have lighted passenger cars?
The reverse module will short out if your train is longer than the loop and anything is crossing both ends at the same time that draws power from the track, such as passenger cars with interior lighting or a FRED on a caboose.
Sometimes just having metal wheels touching the gaps at both ends of a reverse loop at the same time can cause a short circuit.
the isolated part of the loop is a good size but up until now I am only running a loco...no cars. no lighted pass cars, nothing like that. the short has happened when I turn on the DCC with a loco on the track or when it derailed or when going btwm districts. I removed every feeder but one per loop. there should be no prob with 2 reverse modules in the same district assuming it's wired correctly, right? (it is).
the thing with the short is that it does not go away without removing the feeder wires from the power source. I thought maybe the circuit itself is too sensitive somehow.
captwilb there should be no prob with 2 reverse modules in the same district assuming it's wired correctly, right? (it is).
there should be no prob with 2 reverse modules in the same district assuming it's wired correctly, right? (it is).
Only ONE reverse module should be connected to the track. Not sure what you mean when you say you have two reverse modules connected to a district. A reverse module should only be connected to the track within the loop, because only that track should be reversing its phase as the train goes through..
We need a diagram showing where you have reverse modules connected. My impression is that you are creating the short by having two reverse modules connected to the same section of track.
With DCC, your locomotives will go "forward" regardless of the track polarity because the decoder controls the direction. If you have a reverse module connected to the track outside the reverse loop, that is causing the short.
my layout is point to point. each end is a loop. both loops are part of the same power district (both ends are on a lower level). right now each loop has just one pair of feeders and a reverse module connected btwn the power bus and isolated tracks. both loops use the same power bus. each section of isolated track has only a reverse module connected to it.
so, 2 reverse modules connected to the same bus but each to different loops (each isolated) should, itself, not be a problem, right?
captwilb so, 2 reverse modules connected to the same bus but each to different loops (each isolated) should, itself, not be a problem, right?
About the only thing I might add is to take a step back and think basic. The power from the main track feeds to the input side of both reverser, Are the power districts totally separate? The main line rails have to be feed with the same "polarity" For example my out side rail is always red. the out put from the reverser goes to the loop. Could there be a small leakage (short) in the loop so that when something is in the loop you get an overload. How much load can the reverser handle with out shutting down? Do both reverser short out?
captwilbthe thing with the short is that it does not go away without removing the feeder wires from the power source. I thought maybe the circuit itself is too sensitive somehow.
You may be right.
That sounds like there is still a drain on the circuit. If all else fails, try a double pole double throw toggle switch.
Good luck.
Lee
the polarity is correct, I removed ALL feeders but one pair to be sure it was simple. I replaced one of the reverse modules already thinking that was the problem but same problem persists. both modules are MRC units-red and yellow wires, very clear which is which. hard to make a mistake connecting them.
About the only thing left to check is the insulated rail joiners at both ends of each loop.
Make sure they are really isolating the loop by checking with a VOM set to resistance or continuity settings.
You should get an infinity reading when checking resistance across the gap, or no tone if using a meter with a continuity setting.
You need to disconnect the output of the reverse module from the loop when conducting these checks to make sure the module is not giving a false reading, and conduct the checks with no power applied to the layout.
How are the reverse units hooked up? I believe the MRC units have red and yellow wires to it. One set of wires go to the track before the turnout (point end) the other wires go to the turnout past the frog end. The turnout should be isolated on both sets of rails after the frog.The wires to the frog end are attached after the isolated gaps. Make sure both reverse units are wired the same. Joe
The way that you have wired your reverse loops to a separate power district sounds confusing to me. First, a power district is an isolated section of track that is powered by its own booster and the track is double gaped on both ends. A sub-power district is an isolated section of track that is powered from a circuit breaker or power management device and may either be double gaped or single gaped at both ends depending on the device used and the recommended wiring from the manufacturer of the device.
Lets set up a new reverse loop installation.
The turnout leading into the reverse loop should be in the same power district or sub-power district as the revering loop is going to be. The point end of the turnout should be where the DCC power is applied. The two tracks coming from the frog end of the turnout should all be gaped. (Four rails.) No power should be applied to the tracks that are being used for the revers loop, only the turnout. Now lets instal the MRC auto revering module. The two red wires should be connected to the point end of the turnout, using the same DCC power that is powering the turnout. Polarity does not matter for these two red wires. The two yellow wires are the output of the reversing module and they should be connected to the reverse loop track in one place. One yellow wire on one rail and the other yellow wire on the other rail. No other DCC power should be applied to this track section or reverse loop.
That's it, your done and it should work. If for some reason it does not, reverse the two yellow wires. Both reverse loops should be wired the same way, each with their own auto-reverser. The DCC power applied to the point end of the turnouts can come from the same place or a different power or sub-power district.
Elmer.
The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.
(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.
Gandydancer19-
It is connected exactly as you described. I used "power district" when I should have used sub-powered district as I use a 4 circuit breaker board. Red wires to the points, yellow to the loop. There is no power to the reverse loops other than from the auto-reverse modules (each individually).
But what you said about switching the yellow wires make be it...I will try that this evening. many thanks for the heads up...
It sounds like you run the output of your DCC system to a group of circuit breakers, and one of those breakers then is run to the district with the two auto-reversers.
My guess is that the district breaker is faster than that MRC autoreversers, and it's sensing a short and shutting down the district. When it comes back up, the autoreversers are unhappy for some reason. Generally, you want to run the autoreversers directly off the main DCC bus, not through a circuit breaker.
It takes an iron man to play with a toy iron horse.
MisterBeasley,
I did not know an auto reverse module should not be run through a breaker.
My main bus comes out of the booster then into the circuit board and each sub-district gets power from the circuit board. So you are saying the 2 loops with the auto revese should get power that never passes through the circuit breaker? that is news to me (lack of experience)
What MisterBeasley says makes perfect sense. Some reverse modules have an adjustment for current sensitivity .... I don't believe the MRC module has that feature. Reverse modules work by sensing whether there is a short or not and quickly reverse the polarity if they sense there is.
If your breakers are more sensitive to shorts than the reverse module is, then by all means, your breaker is going to trip out before the reverse module does its thing. Try connecting your reverse module main feeds to the buss before the breakers so the breakers aren't picking up that momentary short.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
Well, I cannot say thanks enough to all of you. As a somewhat newbie to a lot of this I had not idea about the sensitivity of the module vs breaker.
as the subdistrict with the loops is has only the two loops within it and nothing else so I will connect them ahead of the circuit and see what happens.
these Forums are priceless, thanks again
captwilb Well, I cannot say thanks enough to all of you. As a somewhat newbie to a lot of this I had not idea about the sensitivity of the module vs breaker.
Don't worry, not very many of us were born with this knowledge. Randy, maybe, but certainly not me. I learned it the same way you did, by making mistakes and asking questions. After a while, I wised up and just asked questions so that I could avoid the mistakes.
Another question about how your layout is set up: I assume that there is a "normal" section between the two auto-reversers which is powered directly from the breaker, right? If you have two auto-reversers wired so that a train goes directly from one to the other, that's another potential problem, as the two will have a hard time synchronizing.
the two auto reverse mods are not adjacent, no. yes the space between them is powered from a breaker.
What brand of breaker are you using? The MRC reverser is not adjustable for different amp settings. Joe
Not born with it, but I did start playing around very young - my copy of the How and Why Wonder Book (if you rememebr those, you're old like me) of Electricty was dog-eared and ragged by the time I was in second grade. For the more detailed stuff - I paid a lot of money to learn that.
True fact: I have yet to build a layout with a reverse loop. And unless I forgot about one, I've built 8 layouts so far, going back to about age 9.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
SUCCESS. Connecting the auto reverse module outside of the circuit breakers did the trick, no shorts and worked flawlessly. Thank you so much for everyone's input....I was so lost for a time there it was great to see a loco run the whole main line last night without problem
thanks again
Thanks for letting us know. I love it when a plan comes together.