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Short on a wye

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Posted by richhotrain on Sunday, February 23, 2020 8:15 AM

mbinsewi

I've been following along, dumb question....for DCC AR function, don't both rails have to be gapped?

Mike. 

For the most part, both rails should be gapped in DCC. The only exception that I know of is the gapping of the inner frog rails on turnouts like the Peco Electrofrog.

Rich

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Posted by richhotrain on Sunday, February 23, 2020 8:41 AM

Mark R.

Everyone's replies are assuming the AR module is actually functioning correctly. It sounds to me like it's not .... especially the comment about switching the wires and the other leg works correctly. I'd be looking at the AR module and verifying it's actually doing what it's supposed to be doing first. The original description of the problem tells me it isn't. 

If the auto-reverser were a "typical" auto-reverser like a PSX-AR or even a lowly Digitrax AR-1, flipping the output wires should not make a difference. But, from what I read, the OG-AR is not a typical auto-reverser. Each of the two output leads provide a specific polarity function.

From what I read, the OG-AR has two outputs: Rail 1 and Rail 2. Rail 1 connects to DCC 1 in normal and DCC 2 when the OG-AR is reversed. Rail 2 connects to DCC 2 in normal and DCC 1 when the OG-AR is reversed. (DCC 1 and DCC 2 are references to the two leads on the input side of the OG-AR).

Here is how Tony's Trains describes the operation of the OG-AR:

The On Guard auto-reverser (OG-AR) can be used to automatically route power to the frog. In addition to the auto routing of power, it also provides a circuit breaker function to protect the switch and your equipment in the event of a derail on the frog. 

Note that when the OG-AR senses a frog in the wrong polarity, BOTH outputs reverse. This is because the OG-AR is originally designed as a reverser, but a frog controller is simply a one rail reverser.

Hence, for the given route, you can predict the polarity required of each frog. Start with the first switch and pick, say, the Rail 1 output. For each switch in the route, decide if it is in phase or out of phase with the first switch. If in phase, connect the frog to Rail 1. If out of phase, connect the frog to Rail 2. Now, when the first frog is touched, all the frogs in the route will be correct. Each switch, if crossed individually, will still flip its frog to the correct phase as required.

The OP is not powering the frogs, so at first glance, this all seems irrelevant. But the fact that the OG-AR is polarity specific leads me to believe that the OG-AR is probably not defective but rather is trying to resolve multiple reverse polarities. It seems to me that this can occur if the reversing section is miswired or misgapped or both.

That's why the OP ought to eliminate those mainline gaps and also check to see if any feeders connected to the output side of the OG-AR are wired to the mainline.

Rich

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Posted by rrinker on Sunday, February 23, 2020 12:29 PM

 The reason certain ARs don;t work with some lower powered systems is that the minimal trip current of the AR is above the rating of the system. So the DCC system will cut out before the AR swaps the outputs. Not always - which is even worse than if it failed every time. It might work with certain locos in certain combinations but then a different loco causes the whole system to short instead of the AR. 

 For an AR to work, it has to trigger faster and at a lower current that the system booster, otherwise it will be like the AR is not even there.

 This layout is a bit more complex than just a simple wye - there are two wyes. Typically with a wye, you just need to isolate one leg. For a simple wye - 4 insulated joiners. On both rails of both diverging legs of the turnout for the leg you are connecting the AR to. 

 That the OP says it works if swapping the wires - it may just be that the rest of the tracks aren't all wired in the correct phase.

                                            --Randy

 


Modeling the Reading Railroad in the 1950's

 

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

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Posted by richhotrain on Monday, February 24, 2020 11:56 PM

IAFlyer
 

I looked at the area west of the yellow marked insulators as one big "reversing section." I am using Atlas crossings as well. 

Rich, when you are talking about "the divergent ends of each of those four mainline turnouts" are you talking about the turnouts marked 17N and 17R? 

FloridaFlyer, you are talking about creating a small reversing section, like the image below? (R being the new short reversing section). The red insulators in this image, I think are needed to prevent a "frog on frog" short. 

(I don't have a lot of posts, so my posts are delayed) 

IAFlyer, apparently your posts are delayed. I just saw your two most recent replies.

The four divergent ends that I was referring to were #2, #3, #4, and #5. You already showed those four divergent ends as gapped, and I agree that the gaps are properly placed there. I see from your latest track diagram that the mainline gaps (colored yellow) have been removed, and I agree with that removal since there is no need for gaps at that point.

I can't speak for Florida Flyer, but I believe that your assumption is correct that he was suggesting a short reversing section. My reaction is to leave everything west of the mainline as one big reversing section.

I am not familiar with the term "frog on frog" short, but I don't see any reason for those two single rail gaps (colored red) on the mainline crossover. Are you certain that all of the feeders from the output side of the OG-AR are wired to rails inside the reversing section, west of the mainline?

IAFlyer

I'm using the OG-AR with a DCC++ controller (connected to JMRI). I have the power coming into the OG-AR from the main power bus, and it goes out to a power district that is powering everything "west" of the yellow insulators.  

I have no working familiarity with the DCC++ base station and controller. How many amps is that system?

Rich

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Posted by IAFlyer on Tuesday, February 25, 2020 11:51 AM

richhotrain
IAFlyer, apparently your posts are delayed. I just saw your two most recent replies.

Yes... I'm up to 7 posts, so hopefully I'll get to the point soon where my posts just appear. The weekend delays approving posts I see. 

 

richhotrain
 

The four divergent ends that I was referring to were #2, #3, #4, and #5. You already showed those four divergent ends as gapped, and I agree that the gaps are properly placed there. I see from your latest track diagram that the mainline gaps (colored yellow) have been removed, and I agree with that removal since there is no need for gaps at that point.

I can't speak for Florida Flyer, but I believe that your assumption is correct that he was suggesting a short reversing section. My reaction is to leave everything west of the mainline as one big reversing section.

I am not familiar with the term "frog on frog" short, but I don't see any reason for those two single rail gaps (colored red) on the mainline crossover. Are you certain that all of the feeders from the output side of the OG-AR are wired to rails inside the reversing section, west of the mainline?

I moved the insulators and rewired the new reversing section (as in my last track plan) and are almost done with it. 

I got the concept of "frog on frog" from this MR page: https://mrr.trains.com/how-to/dcc-electrical/2010/01/how-to-wire-power-routing-model-train-turnouts I don't have Model Railroad going back that far, so I'm not sure if it was part of a larger article about wiring. The problem is I'm using an old track diagram designed for DC wiring and trying to make it into DCC - as a beginner! 

 

 
richhotrain
 
I have no working familiarity with the DCC++ base station and controller. How many amps is that system?
The information I can find says it does up to 2 amps, but elsewhere it says that the software limits it to .8 amps. (it's open source software that is easily changable, if you can figure it out) I just changed the software to allow 1.6amps. I will says that .8 amps is too low. Maybe this increase will help it. 
I'll finish up the wiring and report back on the success or lack of. 
iaflyer
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Posted by richhotrain on Tuesday, February 25, 2020 12:01 PM

IAFlyer
 
richhotrain 
I have no working familiarity with the DCC++ base station and controller. How many amps is that system?

I had seen somewhere that DCC++ is a 2 amp system. That could definitely be part of the problem, if not the entire problem. The trip setting on the OG-AR cannot be adjusted, and it is a 4 amp circuit breaker. So, the DCC++ system may be tripping before the OG-AR can flip the polarities. If that is the problem, you may need to switch to a PSX-AR which can be adjusted lower than 2 amps, down as low as 1.27 amps.

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Posted by richhotrain on Tuesday, February 25, 2020 12:10 PM

IAFlyer
 
richhotrain

I am not familiar with the term "frog on frog" short, but I don't see any reason for those two single rail gaps (colored red) on the mainline crossover.  

I got the concept of "frog on frog" from this MR page: https://mrr.trains.com/how-to/dcc-electrical/2010/01/how-to-wire-power-routing-model-train-turnouts 

You are using Atlas turnouts, and those are not power routing, so you don't need those red colored gaps.

Rich

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Posted by BigDaddy on Tuesday, February 25, 2020 12:18 PM

I'm not sure your new reversing section is long enough, if you are running metal wheel rolling stock.  It should be longer than your longest train. 

I agree with Rich about not needing gaps on Atlas turnouts and have nothing on DCC++

Henry

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Posted by richhotrain on Tuesday, February 25, 2020 12:23 PM

BigDaddy

I'm not sure your new reversing section is long enough, if you are running metal wheel rolling stock.  It should be longer than your longest train. 

If he just leaves the gaps (yellow colored) on the divergent ends of those four mainline turnouts, he should be good to go because everything west of the mainline will be part of one large reversing section.

Rich

Edit Note: Henry, I see what you are referring to. In his reply to florida flyer, he illustrated a short reversing section on the North leg of the wye and removed the gaps on the South leg. I agree with you that the resulting reversing section would likely be too short.

 

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Posted by IAFlyer on Tuesday, February 25, 2020 6:22 PM

richhotrain
I'm not sure your new reversing section is long enough, if you are running metal wheel rolling stock.  It should be longer than your longest train. 

If he just leaves the gaps (yellow colored) on the divergent ends of those four mainline turnouts, he should be good to go because everything west of the mainline will be part of one large reversing section.

 

Edit Note: Henry, I see what you are referring to. In his reply to florida flyer, he illustrated a short reversing section on the North leg of the wye and removed the gaps on the South leg. I agree with you that the resulting reversing section would likely be too short.

Hmm.

So is there agreement that I can use everything "west" of the original yellow colored gaps (on the first track plan) on the divergent ends of the four mainline turnouts as one big reversing section? 

I do agree that's the best for the train length, as the small reversing sections will be way too small. 

 

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Posted by BigDaddy on Tuesday, February 25, 2020 7:03 PM

I vote for everything "West"  I'm not sure why you original setup did not work unless it is incompatibility with the DCC ++ system

Henry

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Posted by richhotrain on Tuesday, February 25, 2020 7:04 PM

IAFlyer

So is there agreement that I can use everything "west" of the original yellow colored gaps (on the first track plan) on the divergent ends of the four mainline turnouts as one big reversing section? 

I do agree that's the best for the train length, as the small reversing sections will be way too small.  

Yes, that was my original conclusion. By gapping the divergent side of all four turnouts coming off the mainline, everything west of the mainline is isolated into one large reversing section. Just be certain that no feeders from the output side of the OG-AR connect anywhere outside of the reversing section.

Rich

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Posted by richhotrain on Tuesday, February 25, 2020 7:12 PM

BigDaddy

I vote for everything "West"  I'm not sure why you original setup did not work unless it is incompatibility with the DCC ++ system 

I think that there are two possibilities why the original setup did not work.

One possibility is that feeders from the output side of the OG-AR are connected to the mainline.

The other possibility is that the DCC++ is reacting faster than the OG-AR, resulting in a short since the polarities remain mismatched.

If IAFlyer reports back that a short is stilll occurring, one workaround would be to disable the OG-AR and install a DPDT toggle switch to manually flip the polarities. If that solves the problem, then the long term solution is to replace the OG-AR with a PSX-AR.

Rich

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Posted by mbinsewi on Tuesday, February 25, 2020 8:01 PM

richhotrain
The other possibility is that the DCC++ is reacting faster than the OG-AR, resulting in a short since the polarities remain mismatched.

Is that like Randy mentions in his post?  The DCC++ is shutting down before the AR.?

Watching and learning... Smile, Wink & Grin

Mike.

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Posted by richhotrain on Wednesday, February 26, 2020 4:41 AM

Mike, at this point we still cannot be sure whether the problem is the gapping and the wiring or the OG-AR until we hear further from IAFlyer.

But here is the issue with reverse polarity shorts. When a reverse polarity short occurs, the current draw can be high, well in excess of 5 amps. Take the NCE Power Pro as an example. It has a 5 amp booster. So, without any other protection, the Power Pro will shut down if the current draw exceeds 5 amps. An NCE Power Cab on the other hand is a 2 amp system and so it will shut down if the current draw exceeds 2 amps. A DCC++ system has a limit of 2 amps but "out of the box", it only draws 0.8 amps, so it will shut down if the current draw exceeds 0.8 amps. Apparently, the DCC++ system can be programmed up to 1.6 amps.

Now, enter the auto-reverser. An OG-AR is a 4 amp circuit breaker/auto-reverser. When a reverse polarity short occurs, the OG-AR will shut down the system if the current draw exceeds 4 amps. But if the OG-AR is part of a DCC++ system, the DCC++ will react as soon as the current draw exceeds 0.8 amps and shut down the system before the OG-AR reacts to the short. The OG-AR does not have a trip current adjustment, so it will only react when the current draw is 4.0 amps or greater.

For the OP, if that is the problem, the OG-AR will have to be replaced with something like a PSX-AR which has a trip current adjustment down to 1.27 amps. In that instance, if a reverse polarity short occurs, and the DCC++ has been programmed up to 1.6 amps, the PSX-AR will trip first at 1.27 amps before the DCC++ system can react at 1.6 amps.

Rich

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Posted by IAFlyer on Friday, February 28, 2020 2:07 PM

richhotrain
For the OP, if that is the problem, the OG-AR will have to be replaced with something like a PSX-AR which has a trip current adjustment down to 1.27 amps. In that instance, if a reverse polarity short occurs, and the DCC++ has been programmed up to 1.6 amps, the PSX-AR will trip first at 1.27 amps before the DCC++ system can react at 1.6 amps.

Here's an update: 

I rewired and created a small reversing section as I indicated in the last track diagram. Nothing changed - I could enter the reversing section just fine from one side, but as the engine exited the other side, the DCC system shut down, like it shorted out. I checked all the feeders to the "yard" and none were connected incorrectly. 

As Rich pointed out, the OG-AR activated at 4 amps, but my DCC is only putting out about 1.6amp, so it likely that the DCC shorts out first. That's why when I reverse the leads, it works the other way (Because the reverser never reverses) I looked into making or buying a booster, but that seems either out of my skill set (making) or too expensive (buying), I'd just get a different DCC system if I was going to get a booster. 

So, the plan is to rewire it a-gain - it's not hard, just moving some insulated joiners, and a little bit of wiring underneath. I'll also get adjustable auto reverser like the PSX-AR or AR-1, to replace the OG-AR. 

Thanks to all.. I hope this fixes the problem! 

 

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Posted by richhotrain on Friday, February 28, 2020 2:24 PM

IAFlyer, before you buy a new AR, or booster, or DCC system, try this.

If you are certain of your gaps and wiring, disconnect the OG-AR and install a DPDT (double pole double throw) toggle switch for manual control. Connect the two input wires from the bus to one end of the DPDT and connect the two output wires to the center terminals on the DPDT. Then, as the loco approaches the short reversing section, throw the DPDT to match up the polarities. It should work if the gaps and wiring are correct. If it works, you know that the OG-AR is the problem.

Rich

Edit Note: If you buy a new AR, spend the extra money and get the PSX-AR. The AR-1 has a mechanical relay and does not interact well when there are solid state devices on the layout. The mechanical relay is too slow and you will have similar performance problems as the OG-AR, but for different reasons.

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Posted by rrinker on Friday, February 28, 2020 3:09 PM

 Tam Valley has a 3amp continuous/5amp trip booster for $1 more than the price of a PSX-AR.

 Just saying.

                               --Randy

 


Modeling the Reading Railroad in the 1950's

 

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

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Posted by BigDaddy on Friday, February 28, 2020 8:16 PM

rrinker
Tam Valley has a 3amp continuous/5amp trip booster for $1 more than the price of a PSX-AR.

You lost me.  What I see is a trip booster board without a power supply and without reversing capability.  How does that help the OP?

2nd product down http://tamvalleydepot.com/products/dccbooster.html

Henry

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Posted by rrinker on Friday, February 28, 2020 10:52 PM

The OG_AR he has will trip before that booster, PLUS he will be able to run more locos than the 1.6 amp capacity of the DCC++ board.

This assumes the issue is the moto shield used in the DCC++ setup is trippig before the OG-AR due to the low current output.

                              --Randy


Modeling the Reading Railroad in the 1950's

 

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

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Posted by richhotrain on Saturday, February 29, 2020 4:28 AM

rrinker

The OG_AR he has will trip before that booster, PLUS he will be able to run more locos than the 1.6 amp capacity of the DCC++ board.

This assumes the issue is the moto shield used in the DCC++ setup is trippig before the OG-AR due to the low current output.

                              --Randy

 

And, for that reason, I would test with a DPDT switch to verify that the gapping and wiring is correct before buying either a PSX-AR or a booster.

Rich

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Posted by richhotrain on Tuesday, March 10, 2020 7:49 PM

IAFlyer
 
richhotrain
For the OP, if that is the problem, the OG-AR will have to be replaced with something like a PSX-AR which has a trip current adjustment down to 1.27 amps. In that instance, if a reverse polarity short occurs, and the DCC++ has been programmed up to 1.6 amps, the PSX-AR will trip first at 1.27 amps before the DCC++ system can react at 1.6 amps.

Here's an update:  

I rewired and created a small reversing section as I indicated in the last track diagram. Nothing changed - I could enter the reversing section just fine from one side, but as the engine exited the other side, the DCC system shut down, like it shorted out. I checked all the feeders to the "yard" and none were connected incorrectly. 

As Rich pointed out, the OG-AR activated at 4 amps, but my DCC is only putting out about 1.6amp, so it likely that the DCC shorts out first. That's why when I reverse the leads, it works the other way (Because the reverser never reverses) I looked into making or buying a booster, but that seems either out of my skill set (making) or too expensive (buying), I'd just get a different DCC system if I was going to get a booster. 

So, the plan is to rewire it a-gain - it's not hard, just moving some insulated joiners, and a little bit of wiring underneath. I'll also get adjustable auto reverser like the PSX-AR or AR-1, to replace the OG-AR. 

Thanks to all.. I hope this fixes the problem!  

I wonder what ever happened to IAFlyer and his layout???  Huh?

Rich

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Posted by IAFlyer on Tuesday, March 24, 2020 10:25 AM

I'm here - I have been busy with dealing with the 'virus. I'm fine, just have the kids home and they take almost all the free time I have.

I have a DCC Booster coming in the next day or two. I decided that the low amperage of the DCC++ system (less than 2 amps) wasn't allowing the Auto Reverser to activate. So hopefully this will provide enough amperage to allow the AR to activate before the DCC shuts down for the short. 

I'll update when I get it put in!

 

 

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