Accessories in Reverse Loop

[ModelerXYZ]

As I have been having trouble connecting accessory decoders together, I have decided to connect each decoder directly to the track. I find it easier to solder droppers directly to the rails. This rasies a question though. A couple of my decoders are under my triangle which is powered by a reverse loop module. Should I put longer wires to the main line or will they be alright connected to the section run on the RLM?

I don't want to run longer wires than needed.

XYZ

[LTSR_NSE]

If you are using DCC accessory decoders (& a DCC powered RLM) then you shouldn’t have any issues, considering DCC is an alternating polarity (or bi-polarity) power supply.

However if you were powering your layout & accessories with DC, (& using a bespoke DC dpdt relay RLM) then this potentially could be an issue, since polarity controls direction for DC motors/solenoids & LEDs/Capacitors are polarity sensitive.

[Fishmanoz]

Agree with LT, they’ll be fine connected to the RL.

And could you do two things please XYZ? Add Loop to your title here and delete you repeated topic?

Mod Edit : All done

[P-Henny]

It would only be a potential issue if you were using DCC Concepts Accessory Decoders and utilising their electrofrog power switching feature on Peco electrofrog points. In that scenario the DCC input of the Accessory Decoder would need to be wired to the track that feeds the toe end of the point it is providing the frog power for. That might be or might not be the RL protected section subject to the point location.

[Fishmanoz]

Paul, are you suggesting that these may result in a short situation?

Without sitting down and tracing out the circuitry, aren’t we still only talking about phase reversal on the track input which will be isolated from any output? And the RL live from the RLM, irrespective of phase?

[P-Henny]

Fishman, Yes it is theoretically possible. Consider this scenario. Due to the physical location of the Accessory Decoder (only applies to DCC Concept decoders if being used to feed a Peco electrofrog). The power input for the Accessory Decoder 'Terminals 1 & 2' is taken from a piece of track within the protected RL section, but the point electrofrog being fed from 'Terminal 3' of that decoder is totally outside the RL protected section, then subject to the phase of the RL section, the feed to the electrofrog could be opposite to the phase needed to prevent a short circuit. Which was why I used phrases such as "potential issue" and "subject to point location" in my original reply.

Such a similar scenario was posted as an issue a few years ago and it was remembering that thread that triggered my reply here. AFAIK XYZ is, I believe, not using DCC Concepts decoders so should not be an issue for him. I was posting for others reading this thread in the future whose layout might fit the stated scenario.

[ModelerXYZ]

So it should be fine? I am using a Hornby decoder by the way.

Thanks everyone!

XYZ

[ntpntpntp]

What was the problem when originally connecting the accessory decoders?

It is usually recommended that you connect the accessory decoders to a separate bus rather than to the trackwork bus. Preferably on a separate power district as that way you don't lose control of the accessories (eg. points) if you have a track short.

I did this with my DCC garden line so that I could retain control of the points when running the track itself on DC or even dead rail for visiting locos having non-insulated wheels.

[Fishmanoz]

Paul, you might like to remove the Ms from your RLMs. I think you are only talking about the RL protected section, not the module controlling it.

I think I can see the issue with the switched frog scenario now. At the point, there is no phase change when the point switches, just the power routing changes such that there is no chance of the loco shorting out that power while on the (now extended) frog. But I think you are saying the fact the power supply to the decoder may change phase at the same time (or any other time) is going to change the phase of Terminal 3 and cause a short?

Even if XYZ were using Cobalts (or similar), should be easy to avoid the problem. He’s using short runs from track droppers to power them in the first place so should be easy to ensure the dropper is on the same side of the RL as the frog. Only power points within the RL from droppers also in the RL, and vice versa.

[P-Henny]

Paul, you might like to remove the Ms from your RLMs.

He’s using short runs from track droppers to power them in the first place so should be easy to ensure the dropper is on the same side of the RL as the frog.

 

 

Done.

PS. I was referring to ADS-2fx & ADS-8fx as well as Cobalt iPs by DCC Concepts in my replies.

With regard your second quoted comment, hence why I said "the Accessory Decoder would need to be wired to the track that feeds the toe end of the point it is providing the frog power for."

But for XYZ this is all academic as he has now confirmed he is using Hornby decoders.