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Power Districts, Options....


Knuckles
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I've started building baseboards for a layout nominally 18' x 11' that likely will have between 40 and 45 points/turnouts powered by DCC.

 

I've calculated the costs and it's scary, but forget that for now.

 

Current plan is to use the Z21 system (old app if it isn't phazed out soon, new app I hate) with Cobalt IPs for points.

 

The layout will mostly only have 2 trains moving at once, sometimes 3 and rarely 4.

 

Stationary loco's/trains could eventually be up to 10 or 15 I don't know.

 

DCC Sound and Smoke on demand is part of the plan.

 

Been looking at power dustrict options and as usual it takes about 2-3 hours of internet searching (been doing it) only to again be unsure what to do.

 

I think the Z21 is a 3 amp ststem. Enough?

 

Not sure I need boosters so DCC Circuit Breakers may be best, unsure.

 

Looking at the NCE EB1's as they might be the answer, wiring them up is simple enough.

 

Have a few puzzles though.....

 

Basically, 

I want to convert to DCC and thinking of using Z21 system with Cobalt ip point/turnout motors and EB1 Circuit Breakers.

1) If I rig those to an accessory bus instead if the track bus doesn't that mean the frog crossings would also be powered by the accessory bus seeing as they go through the Cobalt ip first??  Is this a problem or defeating the object?

 

2) I think the Z21 is a 3 amp system, if circuit breakers are set at 2.5 amps does that mean I'm limiting the full capacity of the system?  Similarly if I set it to 3.5 amps (the next one up) does that mean it'll only work once 0.5amp extra has been used meaning the DCC system may be cooked.

 

Any help would greatly be appreciated.

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18 minutes ago, Knuckles said:

...

Basically, 

I want to convert to DCC and thinking of using Z21 system with Cobalt ip point/turnout motors and EB1 Circuit Breakers.

1) If I rig those to an accessory bus instead if the track bus doesn't that mean the frog crossings would also be powered by the accessory bus seeing as they go through the Cobalt ip first??  Is this a problem or defeating the object?

 

2) I think the Z21 is a 3 amp system, if circuit breakers are set at 2.5 amps does that mean I'm limiting the full capacity of the system?  Similarly, if I set it to 3.5 amps (the next one up) does that mean it'll only work once 0.5amp extra has been used meaning the DCC system may be cooked.

 

Any help would greatly be appreciated.

 

1) - yes, if you power the motors from an accessory bus then you will need to switch the frogs using the track bus( you use the SPDT switch on the motor to do this), not hard, just an extra couple of wires. Ideally you should put an EB1 in the track and accessory bus but if you only use one then it must be on the track bus, with direct feed to the accessory bus. 

 

2) you set the EB1 at 2.5A for the track bus, you want the EB1 'tripping' before the Z21 to ensure that you can still switch the turnout motors when you have a track short. You are not limiting the system, the accessories will be drawing power all the time, 40 point motors will be taking ~0.3-0.5a when not working alone, and then there will be other stuff you power from the accessory bus, signals, etc.

 

My view is that with a layout that large you will quickly be into the need for a booster given your desire for sound, lights and the number of locos - take 100ma for a sound loco with lighting sat doing nothing, then assume 400ma for the same loco running, add on coach lighting, all your other aspects and you will be near the 3a quite soon.what you have described has you at around 2a without adding any lighting or other accessories. As you don't have everything yet I would plan to power everything from the Z21 today, and later be prepared to power the accessories from a booster, then if required split the track into 2 power districts with another booster (or just get a Roco 10807 when you need to split off the accessory bus)

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40 to 45 point motors - definitely have an accessory bus, powered directly from the DCC system’s track output ( not through a circuit breaker).

 

40 to 45 point motors also suggests quite a bit of track.

Problems are likely to occur from time to time, so at the very least, there needs to be some way of dividing the layout up for fault finding purposes.

This could be done by switched sections (only switched to isolate sections for fault finding), or simple plugs (unplug a section for fault finding - which can be cumbersome).

However, more points is potentially more “shorts”, so for short circuit protection and limiting short circuits only to the affected parts of the layout, then those separate sections should be planned as either Power Districts (each powered by their own boosters), or sub- Districts (each sharing the same booster, but separated by a circuit breaker).


Without a plan, it’s hard to say, but  from what you’ve described, the basic overall dimensions of the layout and number of locos that may be present, it’s possible that an extra booster will be useful, if not necessary.

I would still look at sub-dividing the individual Power Districts into sub-Districts, using circuit breakers.

Personally I don’t fancy the EB1 and would look elsewhere (e.g. PSX etc,).

Get the DCC topology right from the beginning, or the risk of having to address issues later on and having to re-wire, could increase.

Don’t overstretch the system’s booster(s). Allow enough headroom and all should be well.

 

Note: Frog power is usually  supplied via track feed connections on the point motor switch, which are separated and isolated from the switch’s  command and power supply inputs.


 

Ron

Edited by Ron Ron Ron
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1 hour ago, Knuckles said:

 

Basically, 

I want to convert to DCC and thinking of using Z21 system with Cobalt ip point/turnout motors and EB1 Circuit Breakers.

1) If I rig those to an accessory bus instead if the track bus doesn't that mean the frog crossings would also be powered by the accessory bus seeing as they go through the Cobalt ip first??  Is this a problem or defeating the object?

 

 

Yes, its a fundamental flaw/feature in the design of the Cobalt IP.   Solution, do not use the Frog switch on the IP, but instead use the second change-over contacts to switch the frog power conventionally.

 

I think DCC Concepts designed the Cobalt IP the way they did for small layouts, without separate breakers.   But, a 45 turnout layout setup needs multiple power districts (if only for fault isolation), and as others have said, it may need additional boosters.

 

1 hour ago, Knuckles said:

 

Current plan is to use the Z21 system (old app if it isn't phazed out soon, new app I hate) with Cobalt IPs for points.

 

 

I'd not build such a large layout based on App control if worried about the design of an App.    The live-cycle for Apps and the hardware devices which run them is very short (year for Apps, maybe 5-6 years at most for hardware), so in the time frame of most layouts they WILL be replaced.    Your statement makes me think "Don't do it with Apps", but instead do the control another way.

 

 

- Nigel

 

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1 hour ago, Ron Ron Ron said:

...

Personally I don’t fancy the EB1 and would look elsewhere (e.g. Switch8).

...

 

I find that the NCE-EB1 works extremely well, the other option is the MERG DCO (but with updated PIC), which is also quite good (and cheap, but you need to build it yourself)

 

Isn't the Switch8 a point motor decoder? - not required for IP Digitals :)

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If you can solder components to a printed circuit board then I would say that joining MERG is the way to go if cost is a problem.

 

District Cutouts are about £10.

Then build the MegaPoints kit (operates 12 turnouts for £30 plus the cost of Servos (less than £3 per point incl mount).

 

Big savings to be made.

 

Dave

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52 minutes ago, WIMorrison said:

....Isn't the Switch8 a point motor decoder? - not required for IP Digitals :)


Oops, slip of the brain over morning coffee, with the distraction of Mrs. Ron issuing the day’s list of commands, in the background.

 

Much like DCC, these commands will be re-broadcast at frequent intervals, until complied with.

 

 

Ron  :rolleyes:

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For power districts I have been using DCC Specialties PSX circuit breakers. Very happy with them. For fault finding you can turn each district on and off with a CV setting which avoids having to physically disconnect bus wires. You can also tune the trip current on each section individually with both jumper connector blocks and CV settings.

 

For your cobalts yes power the motor from the accessory bus, and power the frog from track power into one of the independent cobalt switches to maintain electrical separation of accessory bus and track power. Cobalt IPs have 2 independent switches, Cobalt digital IPs have 1 independent switch.  I think they both also have one switched output from the motor feed wires but in your set up that will be from the accessory bus power so use one of the other switches for the frog. 

 

For power, sound loco chips and lit coaches can consume a lot. I am using about 2.3 amps now from an NCE 5 amp system and I still have lots of point motors to add. So give yourself the option of more power later if necessary. Good luck, Tom

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1 minute ago, Dominion said:

For power districts I have been using DCC Specialties PSX circuit breakers. 

When this product first appeared, replacing DCC Specialities original Powershield, it was claimed that the PSX could detect the difference between a true short and the inrush of current typical of a lot of sound-equipped locos restarting after a short circuit had reset. Whether more recent competing products emulate this ability I know not, but I like the PSXs, too. 

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One thing to consider for a home layout where you are most likely the only operator, is whether you want only one part of the layout to shut down if there's a DCC short rather then the whole layout. That's why I stopped using multiple circuit breakers. If there is a short, most often caused by running a turnout set the wrong way or a derailment, then I do want everything to stop so that I can focus on the problem.  Might be different for a large club layout with multiple operators though. 

 

Therefore using a single circuit breaker, but having the layout wired in sections that can be easily switched out, is what I have done. Either feed each section through DPDT switches or simply connect the wires via Wago connectors or similar. This allows me to disable sections when an unexplained short occurs. Fortunately, once the layout is built and fully tested, unexplained shorts should be a rare occurrence. 

Edited by RFS
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1 hour ago, RFS said:

One thing to consider for a home layout where you are most likely the only operator, is whether you want only one part of the layout to shut down if there's a DCC short rather then the whole layout. That's why I stopped using multiple circuit breakers. If there is a short, most often caused by running a turnout set the wrong way or a derailment, then I do want everything to stop so that I can focus on the problem.  Might be different for a large club layout with multiple operators though. 

 

Therefore using a single circuit breaker, but having the layout wired in sections that can be easily switched out, is what I have done. Either feed each section through DPDT switches or simply connect the wires via Wago connectors or similar. This allows me to disable sections when an unexplained short occurs. Fortunately, once the layout is built and fully tested, unexplained shorts should be a rare occurrence. 

Interesting approach, and not one I'd considered.  To be clear, you mean one circuit breaker (PSX or A N Other), but with separate [power districts downstream of it switched separated simply by switches. Short occurs, switch out each district until system recovers?

 

It would certainly mean a short on the "far side" of the layout wouldn't go un-noticed..........

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I too use PSXs for the track busses  - A very useful feature is how they keep retrying every 2 seconds to restart the protected area -... so on a large layout you can walk over the the problem, and correct it, and th etrack is automatically reinstated - never having been cut at the controller

(Of course, I also use Multimauses - corded and wireless, so I carry  / can carry the control for locos and pointwork with me, anyway)

 

When I bought an NCE PB3 many years ago it was only rated for 16V track voltage, and not the full dcc system capability - in fact it failed to work correctly on higher track voltages .  ( I originally  Roco with a transforrmer which gave higher track voltages when there was little or no load - resolved by using SMPS supplies as now supplied by Roco and other European manufacturers due to CE regulations for energy efficiency)

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6 minutes ago, scottystitch said:

Interesting approach, and not one I'd considered.  To be clear, you mean one circuit breaker (PSX or A N Other), but with separate [power districts downstream of it switched separated simply by switches. Short occurs, switch out each district until system recovers?..........


“Sub-Districts”.

A Power District is a section or zone powered by its own individual Power Station (i.e. Booster).

 

Dividing a Power District by the use of circuit breakers and switches (in whatever combination), creates sub-districts of the same Power District.

 

Ron

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23 minutes ago, scottystitch said:

Interesting approach, and not one I'd considered.  To be clear, you mean one circuit breaker (PSX or A N Other), but with separate [power districts downstream of it switched separated simply by switches. Short occurs, switch out each district until system recovers?

 

It would certainly mean a short on the "far side" of the layout wouldn't go un-noticed..........

 

Most shorts have known causes, so when one occurs it should be easy to resolve. The reason I operate the way I do is to be able to deal with the short/derailment without other trains running unattended which could cause further issues.

 

For example, I have a pair of Bachmann 4-car class 411s running in multiple. If a short occurred in one power district whilst the consist was between two power districts, one unit stopped dead but the other tried to continue. In the end I found whenever one district suffered a short and powered off I was invariably having to hit emergency stop to prevent further issues. 

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Like RFS I want the whole layout to shutdown, I don't use psx devices but as I have 7 boosters for track supply these split the areas into smaller sections. As I use a computer with track detection and a short occurs for what ever reason the computer shows this on the mimic display as all detection in that area goes occupied. As a development on this I'm going to put a psx between the boosters and the main bus feeds to the detectors, the psx have the ability to output a state and I'm going to set up a sound notification as sone as a short occurs.

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I had a short occur on my loft layout, when I had a visitor.  A loco had derailed - so that was the logical location of the short ... except it wasn't there (or if it had been, after it was cleared, there was then another fault....     I had to use a multimeter to find the point of lowest resistance .....

(having initially reduced it to part of a sub-district due to my being able to isolate areas 'geographically ... to 1 board... my Ilfracombe Terminus.

The problem ??? When the derailment occurred, I must have had a 9V metal clad battery in my hand, and put it down (on the Ilfracombe Track) when I went to sort the derailment .... leaving the short still in place and unrelated to a train movement 8-(

 

A reason for having the sub districts and further isolation available locally within them, is a story from when I started with Zero-1, and the layout was 1 whole section (although I did separate off the accessoroies due to the APT triggering nearby accessory decoders !)

The layout ( the earliest version of Beechingless Barnstaple - converted to Zero-1)  filled my parent's loft (about 5 x 3m on 1.5 levels).

Luckily only 1 train had been moving when the short occurred  .... but i a tunnel, comprising plain line !!

I ended up lifting the points at either end, to confirm the fault was still withing this 2m of track ... it was...

A single strand of wire laying in the ballast must have been knocked by the passing train - its origin a mysstery - but its removal cured the problem.

Ever since I have ensured that any layout can be divided electrically to make fault location easier.

 

Shorts do not necesarilly occur in an obvious place, or from an obvious source.   I monitor current and volltage in each power district (4 in the loft)  [ voltages only on the portable layouts using 'car' 0-30Vdc displays  and a bridge rectifier ]

and have LEDs on the track-side of the central isolating switches {That way they identify if the section is receiving power by something bridging the gap to an adjacent section ... also being an inbuilt aid for any continuity test 8-)

 

After an 'unexplained' fault /overload on our transportable skandi layout, I have now also added traditional resettale circuit breakers for the accessory bus,  12V lighting circuits   (and now redundant 16Vac).    I am now splitting the 12V lighting distribution into 2, because the progressive addition of scenic and platform / street lighting has increased the current to nearly 6A and a warm connector ! 

 

Whilst the government are now more honestly admitting that 'Smart Meters' are to help monitor the power loading continuously ... there is an advantage to, at least being aware of, knowing the actual current / power demands of ALL parts of a layout.

 

 

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Wow!

 

I didn't expect such a collective response, so many thanks to ye.

Much appreciated.

 

I'll refrain from a detailed reply just ywt as I need time to digest all that has been said.

 

However I'll touch upon a few pointers: I've wired 3 layouts up so far in DC, 1st with Tortoises and the rest with Solenoids and CDU, the 2nd layout had 3 separate track circuits  and an auxillery for points so I got the concept at least.  Just unsure how best to go about this beast.

 

Baseboards are 85% completed.

 

The plan is here..

 

https://mobile.twitter.com/KnucklesSCC/status/1188883742250717185

 

The coloured tracks are how I'm thinking if separating the wiring into districts but this can changed.  It's how I'd do it for DC (with isolator switches) although in DCC maybe make the double track main line a single district.

 

The Cobalt IPs interest due to the decoder being built in abd with such a big solo project reducing wiring is high up there, although secondary priority.

 

The dufference between the other Cobalt motor I'm unsure if.

 

Would it be easier to keep the points and things as part of the track circuits but keep them within the coloured track districts?   That way it'd still be split up nicely.

 

Anyway, as above I'll read over your replies, if ye see any insights from the track plan please advise. 

 

Note: there may be a fiddle yard in the center but the center is modular to switch scenes etc.

 

Note 2: five of the points I may not be rigging to a motor, undecided.

 

Many thanks :)

Will reply later.

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Not a DCC comment, but this is an ambitious layout. It will be lovely when it's finished, but Rome wasn't etc. Make sure that your stageworks allow you to have some operating fun at every stage. Running trains is really good for us - and not being able to do so because there is a lot of hard graft before everything is sorted can really thwart enthusiasm. 

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Plan looks interesting with potential for lots of movement - it would work really well with automation on at least the continuous part where you could have several trains running simultaneously whist shunting manually in main station and yard - although you could automate them also, perhaps later though.

 

i would plan to build in automation from the start - even if you never automate it, much easier then that later and won’t affect layout if you never automate.

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It is a big project but I've got over 100 Anyrail files over 7 years of constsnd redesign, each edited multiple gimes trying to shuffle all this together optimally so I'm pretty determined.

 

Plan is go build the smaller Junction stagion 1st, the track and electrics to get stuff moving and then move on to the beast.

 

Must admit though, automation is something I have zero interest in.

 

Plan is trains will be stored in the terminus and the lines above, a pilot can also shunt some rakes in.  Train leaves and can do a few laps or stop at a signal and a 2nd train leave, then 1st train move to next  area or station then it can go around into the middle (several removable scenic passes for filming) and either there or at the junction do a run around and return to the terminus.  Mean while, shunting can happen at the junction and loco's can be moved about the MPD.

 

That's the general idea, but automation isn't for me.  :-/

Maybe one day.

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The central cross route .... Isn't this going to restrict your freedom of movement ?? (and also missing the opportunity at present to be a parallel set of passing loops   )

Have you considered running that section beneath the station in the upper part of the diagram?.....any gradient required for extra clearance could be 'halved' by having the upper level  slightly higher than the lower station, and the 'hidden loop' dropping slightly.

 

Ideally I would recommend trying to  get at least 20cm gap ... Enough to reach in over the nearest track to reach the furthest track.

I admit my loft layout uses a 10m incline round the outside edge to do this, BUT the alternative .... Which would allow a very large separation such that U:S. Style both levels could be scenic .... Would be to use a helix to change level .

 

We use a 3.5 turn helix in our portable skandi layout to double-up on the effective size by being able to run from the upper level, through the mid level, to the bottom level, and back up without stopping the train ... So trains can depart and have a run before returning to the upper level.   So a  5.4m x 1.5m layout has 3 'independent' loops on its 3 levels ... With the ability to move from one to the other as required  (and  between upper and lower without interfering with the middle level loop as it has a helix-bypass link.)

 

 

Edited by Phil S
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I agree that it might not be for you at first glance, but I wouldn't dismiss automation totally if I were you as you have a track plan that looks very complete and it would be a pity to see limited movement when with a modicum of effort you could have lots of movement under automated control whilst still enjoying manual control of any areas that you want to ;)

 

And, in a few years time when you see the benefits (as more and more people are), it would be a pity to have to start changing things when it could be build to accept it later - should you decide you wanted to go that way.

 

As you have spent 7 years getting to this stage, just think where you could be in another 7 years when track is actually down and trains are moving - although maybe not as many as could be ;)

 

Just saying ... (but as the phrase goes - it your trainset!)

 

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13 hours ago, Oldddudders said:

Not a DCC comment, but this is an ambitious layout. It will be lovely when it's finished, but Rome wasn't etc. Make sure that your stageworks allow you to have some operating fun at every stage. Running trains is really good for us - and not being able to do so because there is a lot of hard graft before everything is sorted can really thwart enthusiasm. 

Agreed.

My layout is 15x8 with 26 points. Track power is done so I can run trains but I ran out of puff when I got to the control panels, so have a load of colour-coded wiring back to where they should be.

I have now decided to use a separate DCC system (MERG) for these.

 

My trains do not run from one power sub-district to the next except via a seldom-used crossover. Instead I have 1 sub-district for each of the 3 pairs of lines. This does not seem to be the usual way to split up a layout into sub-districts but I felt it was more logical.

I find this useful because if there is a short (invariably a loco run into a frog) then I can see from the breaker indicator which circuit this is. I can easily halt the layout using E-stop.

By having sub-districts, it will allow me to easily change these to districts by adding a booster if I need, 1 5A supply has so far been sufficient.

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