using elink for accessories

[Yelrow]

greetings to try to get round my melting points i propose to wire up the elink as controller B and use only for my points and Turntable. To this end i have fitted insulated joiners where turntable and circuit connect.If i now connect elink to my points decoders they should work without conflict as no power is going to the track. My turntable is 0022 in RM and due to insulated joiners at present cannot feed back to the track. When i click on schematic,it moves only on screen, as no power to motor from layout . In order to give a supply,i propose a new lead from track output to turntable motor, which if i am correct,will then make it move from schematic. Now you clever guys, will this solve my problem with both. I presume locos moving fro track to turntable will be fine as impetus will carry them across insulated joiner, picking up fresh power, once across.i presume then i can drive them on RM, reverting to elink, if i wish, once back on the track. I would value your early imput, as it has taken me ages to come up with this, and i am fearful that i may have missed an obvious problem. john

[poliss]

You have a reverse loop module on the turntable bridge?

[Yelrow]

Poliss sorry, you have lost me. Prior to melting points, the turntable was fitted in centre of layout, with one siding leding into main circuit. All 18 tracks from it, were powered to allow trains to go into engine sheds etc. Then i had the melting points, which i initially put down to selenoids, so dis connected, but they still melted. I then wondered if it was a reversed polarity thing, when TT, went the other way, so bought and fitted these insulated joiners. Circuit now fine, and no power passes to tt, from track. Does that help. If not, you will need to explain further, me being a simple brain. john

[Chrissaf]

John,

Just as a point of clarification and if I understand you correctly.

The Elite as controller A will power the main track.

The e-link as controller B will power the point decoders, the turntable drive motor, but also provide power to the rotating piece of track located on the turntable bridge.

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If my understanding is correct, there is an issue with this configuration with regard to the text highlighted in bold. If my understanding highlighted in bold is in fact incorrect and e-link controller B will only be used to run the turntable motor in isolation and NOT be connected to the turntable bridge track then ignore this post completely.

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If my understanding is correct however with regard to the bold highlight text, then when your locos transit across the turntable bridge from the main track to the turntable track then you will produce an electrical connection via the loco wheel sets between the outputs of your A & B controllers that they will not like at all.

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By all means run the turntable motor in isolation from e-link controller B, but any power on the actual turntable bridge track should come from Elite controller A.

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With the Turntable Bridge track completely isolated because of the insulated rail joiners, then you will need to power the bridge track from controller A via a Reverse Loop Module as poliss suggested. Unless of course it has something called slip rings. I daresay Fishman will provide you with one of his detailed step by step instructions regarding reverse loop modules vs slip rings when he appears.

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[poliss]

If the tracks on the turntable are powered all the time, then when the loco is turned the polarity will be reversed on it. You will get a short circuit when you drive the loco off as the wheels on the loco will be getting power from two sources of opposite polarity as they bridge the gap.

If you are powering the turntable from the eLink and the rest of the layout with the Elite (that is not connected to the eLink) then it will have the same effect as using two DCC controllers. Very bad idea and could damage both controllers beyond repair.

[Yelrow]

Chrissaf, ah well, then we come back to the melting points. My understanding was in some way, power was feeding back from tt set up to track, hence melting points. I am not very up on DCC turntables, and it came, fully wired to all the outputs, i simply connected the track, and prog decoder. It worked a treat for weeks, until i noticed my melting points, only by chance when i put a hand on the point, and got a nasty burn. So i thought i could run as described, but felt sure, i was making an error in my reasoning, but did not know where. So are you saying that  when i run a loco from the point powered with elite/ rm, across the insulated joiner, it will pick up power from the elink. If so, thats my  archilles heel. Do you have a solution. john

[poliss]

The way to fix it is to forget powering the turntable from a seperate source and instead fit it with a reverse loop module.

[Chrissaf]

John,

I edited my earlier reply with an additional paragraph at the end.

[Chrissaf]

John,

Whilst waiting to see what Fishman might reply with, have a look at this web page. It gives a good description of Turntables wired with option 1 using a Reverse Loop Module and option 2 using split rings.

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http://www.brian-lambert.co.uk/DCC%202.html#Turntables

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The general consensus of opinion regarding your melting points issue was that somehow your TT was creating a resistive short (a short that was not clean enough to trip your controller). A Reverse Loop Module when installed correctly should eliminate completely any potential for a short to cause a problem. The way a RLM works is that it monitors the track it is connected to. As soon as it starts to detect a short occuring it reverses the track polarity to remove the short condition from developing. This happens blindingly fast, so fast that even a sound loco doesn't stutter with any detectable sound drop out. In theory, if your TT has a slip ring then a RLM shouldn't be needed, but given your problems it might be worth going 'belt 'n' braces'. It might be that your TT doesn't have slip rings implemented which could account as to why you might have been having your melting points issue in the first place.

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The Hornby RLM is part R8238 https://www.hornby.com/uk-en/hornby-dcc-reverse-loop-module.html

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There are others out there cheaper. I used one from Tam Valley part number DFJ003 for £21.50 this one is uncased and is an open PCB construction, hence the cost saving against Hornby's £39.95.

[Yelrow]

Chrissaf, hi thanks, obviously back to drawing board, i am fairly sure that my frateschi TT, has slip rings, but quite happy to have  reverse loop module. I know Tam valley, well as have their DCC shuttle, put onto them, by Brian Lambert. At least i can proceed with part one, using elink for points, as no  objections have come forth about that. What i cant understand is why tt worked for so long without any problems. john

[Fishmanoz]

John, I'm at least partly with poliss and Chris on this. I do have some further thoughts though.

 

For a start  - you cannot have 2 controllers connected to any part of your track, even if the second is only connected to the turntable bridge and you are using IRJs.  As soon as you start to drive a loco from one part to the other and have a set of wheels with pickups on each side of the IRJs, the two circuits are joined together and both controllers will trip to avoid catastrophic failure to both of them and everything on your layout will come to a stop.  For you there is one advantage - your points won't be melting - but this is not the way to stop them.  Just forget about a second controller to the TT Bridge.

 

If I remember correctly, your TT has only one track connected to your layout? If this is so, you don't need an RLM to run it, even if it is a slip ring design.  It is true that half your outlets will be at reverse polarity to the other half and your layout.  But you can fix this easily by identifying the ones that are reversed and swapping the power feed wires to them.  Your wiring must be set up over the rest of your layout such that feed wire A goes to track A and wire B to track B.  Well on the reversed outlets, you just do wire A to track B and wire B to track A.  If you don't do this, you should get a short that trips your controller, but if as Chris suggests you have non-perfect connection then it may be only "resistive" and not enough to trip the controller.  But in this condition, it will be drawing a lot of current which can heat up the resistive imperfect connections at your point blades and DCC power clips, hence the melting while this condition exists.

 

Now my final point - none of this is going to be fixed by using a second controller for anything.  There is nothing wrong with having a completely separate bus and controller for your points and to control the TT (as opposed to running the bridge), but it is highly unlikely to fix melting points.  At least not unless the fault is a faulty accessory decoder which is drawing high current, but let's assume not for now.

 

I'll just be off now to check your TT manual, pretty sure I downloaded it to check out how to run it when you first got it, but I'll get it if not and confirm what I've said or not after a look.

[Fishmanoz]

Just another thought - if I'm wrong and you do have a second track connection from the TT to the layout, and it is one of the reversed ones, then you must use an RLM.  It is an either/or though.  Either you do have a second connection which is reversed, and you do need an RLM, or you don't have a second connection and you don't need an RLM.  That's assuming your wiring polarity is correct and getting an RLM to insure against doing your wiring wrong seems like a waste to me.  Just check the wiring and get it right.

[Fishmanoz]

Failed to find a manual but there is a thread on it, it is a Frateschi 4500 I think, that covers it called DCC and Turntable and has the wiring diagram at least for DC.  It is a slip ring design it seems so what I said earlier applies.  And it seems that the outlets opposite the inlet are the reversed ones.  Put another way, 90 degrees either side of the inlet are the same polarity, and everything beyond 90 degrees is reversed.

 

So john, I suggest you put everything back as it was, points connected and no IRJs, then correct the polarity of those outlet wires, use only one controller, doesn't matter whether eLink or Elite, and give it a try.  Try turning your TT to each outlet and see if any of them make the melting points warm.  Use your finger to test that, and I take no responsibility if you catch alight by the way.

[Yelrow]

Fishy, thank you, very detailed as ever, and i almost understand it. In view of my age and disability, i only have  2  q uestions . i do not want to spend hours, lying on my back, reaching up to all the wires. If i bought and fitted a Reverse Loop Model, as is now, would that save all my time and labour, and let everything function. I am facing female resistance to laying on the floor in view of my knees, and she suggests that £25, if thats what would solve it, is cheaper than a lot of pain.  You are correct that only one rail to track, but all 18, tracks are wired to be live. One last point, none of the tracks that go to tt bridge, have insulated joiners at bridge end, as there is a reasonable gap between them, and the bridge, but i notice on brians site, he has insulated both ends of all rails. john

[Fishmanoz]

Hi john, yes it should work if you use an RLM to power the bridge.  If I have interpreted the wiring diagrams I mentioned correctly, the bridge is connected to power from the inlet track by separate wiring.  You will need to find this connection and break it, then power the bridge from the outlet of the RLM instead.  Doing this means that it will switch the bridge polarity to match inlet or outlet as your loco runs across.  And if you don't isolate the bridge by breaking that connection to track, nothing will work anywhere on your layout I don't think.  Certainly the RLM won't  

 

Given you say there are gaps at the ends of the bridge rails such that they do not directly connect to inlet or outlet tracks, I don't think you will need IRJs.  In fact, if you put any in, you may well end up with dead track between the IRJ and its junction with the bridge.

 

Now I am not 100% certain on this as those wiring diagrams aren't fully clear to me but irrespective, you aren't going to do any damage by trying it.  Tell us how you go.

[Yelrow]

Fishy, hi, thanks, i am going to have my knees injected with silicone type product today, so will be out of commission for stair climbing. iam going to remove elite, pro tem, replace with elink on 1 amp transformer, replace, point wires atc, to be back to where i was , doing as you suggest, but using lower power, while i fiddle. I wll buy  a reverse loop, as only £21, and if all else fails, as you say, it will work. i put it back as it was, and test, whilst i await  its arrival.  When i bought the TT, it all came fully wired, with all exits numbered, and i just joined the dots. Will report back, asap, plus a bit. john

[Fishmanoz]

A couple of things. First that thread I mentioned in my third post above is on RMWeb.

 

Second, if you are buying a Hornby RLM, it will only operate reliably with the 4Amp supply, not 1Amp.  Didn't mention before as I know you have 2 such supplies.  Have no idea if any other brand of RLM might have this limitation. I can only suggest that old standby - read the documentation that comes with it.

[Chrissaf]

As a user of the other brand mentioned in this thread, namely the Tam Valley DFJ003. I can confirm the following. It has a link position to select two different triggering currents. The user guide nominally calls them the 2 amp and 4 amp settings. Don't know about the 4 amp setting, but the 2 amp setting actually triggers at 1.7 amps. I use four of these with a Hornby 4 Amp Elite PSU and they work absolutely fine on the 2 amp link setting. The manual says that the 4 amp setting shouldn't be used with a PSU less than 5 amp. The Tam Valley web site talks about using the 4 amp setting with their 10 amp Boosters. 10 amps must be a US thing, as not typical here.

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Needing 1.7 amp current detection to initiate the trigger condition means that the DFJ003 is NOT suitable with Hornby's 1 amp PSU.

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Fishman, one question of clarification. You stated "Second, if you are buying a Hornby RLM, it will only operate reliably with the 4Amp supply, not 1Amp." I notice on the product page that the Hornby RLM is shown with a 'Select' / 'Elite' selection slide switch. Are you saying that when the Hornby RLM is in the 'Select' position it should work with the 1 amp PSU, but some have found it doesn't?