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StanierBlack5

Isolating power districts

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The more that I'm learning about building my first layout, the more confused I become, I would really appreciate your guidance with regards to the following:  Theoretically, if I had two oval tracks one inside the other, each having their own separate bus wire and connected together via two sets of electrofrog points (to enable a loco to change from one track to the other), to keep the two districts separate would I need to use nylon insulating rail joiners between the two sets of points? I forgot to mention that my layout will be DCC.

 

Please see the attachment and many thanks in advance.

Roger

 

Separating 2 Districts.jpg

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I would put the nylon rail joiners exactly where you have indicated.

That is how I have separated my power sub-districts. I have not had an issue, nor did I expect one.

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On that size of layout you don’t really need multiple power districts. 
However, DC or DCC, single or multiple power districts, you would need to insulate as per your diagram

Edited by Talltim

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Thanks for raising this topic. I am a DCC newbie but helping someone to lay track on a DCC layout.

 

The layout concerned will be rather more complex and I had been wondering about this issue of multiple districts and where the isolating rail joiners would be needed. As I understand it, once all the districts are turned on, operation of the locos is unaffected as they pass from one district to another. But if a short (or other problem occurs) in one of the districts, at least it does not shut down the whole layout.

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Thank you both for your quick replies.

 

Talltim, trying to keep my question simple is the reason for mentioning two separate ovals, my layout will have two main lines (one up and one down), two goods lines (up and down) plus a six road carriage sidings and a smaller five road wagon sidings, all together I'll be using 28 sets of points at this point in time! Later I will be adding a turntable, shed and coaling plant etc., the layout base is 9' x 8'.

 

Joseph, I too am a beginner and am loving building my layout which at the moment has stalled as I am awaiting stock of the iP Cobalt Digital point motors coming in to stock, meanwhile I'm still mentally building it and getting help from this very good forum.

 

Thanks again fellas!

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Hi SB5,

 

The picture you gave above, with red dots indicating nylon joiners, is correct for isolating the frogs on a crossing.  Each frog is nicely isolated from the next piece of track.

 

However, and just checking here for completeness of clarity;

You talk about power districts and your image says ‘district 1’ top right and ‘district 2’ bottom left.  Are you intending the top line (say outer circuit) is district one, and the bottom (say inner) is district two?

If so, again, all good with with how you have shown it.

 

But if you mean both lines going right are district 1 and both going left are district 2, then you need additional nylon joiners in the outer stock rails as well.

 

Also,  are we correct in assuming that you have one command centre and no separate power boosters in play?

 

Cheers,

Paul

 

P.S.  shop about for those digital cobalts, they’ve been out of stock for over a year and sell fast.  Ignore the big boys, try the smaller shops.

Hattons had some 6 packs @ £130 p/pack last week but they went straight away.  I wouldn’t hang on for the 12 pack for a saving, looking like £250 min for a 12 pack now!

 

One model shop has the 12 pack on eBay and is selling them at £320.

That’s £20 over the RRP!

Edited by bigP

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Hi bigP,

 

Yes, in the diagram District #1 would be the top line and District #2 would be the bottom one.

Yes, I have one command centre (NCE Power cab) and no power booster.

 

Thanks for the digital Cobalt info and it now looks like it's going to cost heaps for 24 points!

 

bigP, many thanks for your input.

Roger

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When deciding on power districts is easy at the construction stage to put in to many power districts

Depending on the size of the main lines it might be wise to divide each one into multiple power districts.

Loco facilities & Yards could also be separate power districts

The drawings show several ways to feed the power districts

1             While this is the simplest fault finding is very difficult &, short circuit protection is provided by the Booster                               

2a           Fault finding is a little easier ie disconnect wire from terminal strip until fault goes away

2b           Fault finding is easiest, just turn off switches until the fault goes away

3a           Short circuit protection & fault finding are provided by the circuit breakers                          

3b & c   Similar to each other but “b” uses less breakers & switches to aid fault finding

4a           Shows an extra booster connected to the system

 

873071207_powdiscts.jpg.b6d237411bbfe4b55981044b5e9acab5.jpg

 

All these circuits show only one wire from the booster to the track, the second wire is a duplicate of the first wire

If you decide to put switches between the booster & the track then you only need to switch one wire

One advantage of switches is you can turn off parts of the layout

 

With 3 or more sound engines idling in the background I find the silence is deafening when I turn off the layout

 

John

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2 hours ago, StanierBlack5 said:

 

....Yes, I have one command centre (NCE Power cab) and no power booster.

 

 

Hi Roger, 

 

Being a bit cheeky and pedantic, you do have a power booster!

What you have there with the PowerCab is a Command Station and a Booster.

The PowerCab is unusual in that the system's Command Station and tiny Booster are contained within the PowerCab handset itself and not in an external box of electronics.

 

However, on a more pertinent note, I agree with what's already been said about dividing your layout up into manageable sections, primarily for better handling of shorts and for easier fault finding.

It may be worth considering one (or more) of the short circuit protection devices (circuit breakers) described by others, so that you can split the layout's single Power District, into two or more sub-districts, each protected by circuit breakers.

Further division using simple switches, as described by John ks above, would be worthwhile insurance for fault finding as well.

As John demonstrate, there are many ways to skin this cat.

 

Of course none of this is necessary at all.......until the day you get an annoying short circuit or electrical fault that proves difficult and time consuming to trace and rectify....

.....or not necessary at all.....apart from the times when you get increasingly frustrated at the whole layout shutting down because of a local short on a small section of the layout, that ordinarily shouldn't affect running elsewhere (e.g. on a separate loop of track).

 

Cheers

Ron

 

.

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22 hours ago, Joseph_Pestell said:

 

 As I understand it, once all the districts are turned on, operation of the locos is unaffected as they pass from one district to another. But if a short (or other problem occurs) in one of the districts, at least it does not shut down the whole layout.

Mine is 3 sub-districts all run from 1 booster through separate circuit protection devices. 1 of the sub-districts is isolated, but there is a crossover between the other 2. Running a train between these 2 is a non-event. I forget they are passing from 1 sub-district to another.

 

It provides me with 2 benefits:

If a short occurs (usually a loco passing the wrong way through a point set incorrectly), only 1 power district cuts out, which makes finding the fault much faster.

Although it looks unlikely, if in future I do use more current than my booster can supply, I can add a second or third booster. Unlike upgrading from a 5A to 10A system, the wiring still only needs to take 5A because you are splitting across separate circuits.

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Have to agree with the sentiments of the above.  Much simpler to think about and plan in power districts, circuit breakers, etc etc now before you start laying track and wiring the layout.

 

If you are using circuit breakers then you might want to consider feeding your cobalts through a separate channel on the circuit breaker.

Nothing worse than something shorting over point work, only for the points to reset when the short clears and thus create another short.

 

Also, if you’re thinking you might exhibit, make the fiddleyard fully isolated from the scenic section.  Nothing more frustrating than seeing that crack Up Express come to a dead stop because someone just shorted the fiddleyard whilst changing some stock!

Edited by bigP

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2 hours ago, bigP said:

......If you are using circuit breakers then you might want to consider feeding your cobalts through a separate channel on the circuit breaker......


In other words, an Accessory Bus....a separate branch off the Power Bus output from the DCC system.

The Accessory Bus doesn’t need to be fed through a circuit breaker though, as it’s rather pointless (doh !!! :yahoo_mini:  :biggrin_mini:).


Therefore a two channel circuit breaker could provide for 2 sub-districts, each with their own track bus, plus a separate accessory bus.

Likewise, a four channel circuit breaker could provide for 4 sub-districts plus an accessory bus.

 

 

Ron

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No, I mean a separate channel out of the circuit breaker, not a dedicated accessory bus.

The Cobalt Digital IP has in-built switching of frog polarity.  So, if you get a short across the frog powered by one, down goes that Cobalt, and anything attached to the same sub-bus.

 

If that ‘sub-bus’ is an accessory bus connected to the command station without circuit protection, we’ll down goes the CS too.

 

Unless of course you try more wiring though switches 4, 5, & 6, or don’t use the Cobalt for switching frog polarity at all, then as you you say, use an accessory bus.  However, if the latter then you need to spend more money on something else to switch those frogs.

 

Paul.

Edited by bigP

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Many thanks for all your replies and advice, I now have a lot more to think about before I go any further.

 

Thanks also to the internet and top forums like this one now that the digital age is truely with us, back in the day with DC, I'm sure that building a layout was not as complicated for beginners like me.

 

Than you all and Cheers,

Roger 

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1 hour ago, StanierBlack5 said:

back in the day with DC, I'm sure that building a layout was not as complicated for beginners like me.

 

'Back in the day with DC', I accepted poor running to be normal. I am now much more demanding about how well my models run (especially at slow speed). I am sure others are the same.

The complexities are chosen by many to make things more reliable.

 

You could compare this with cars. In the 70s, most had carburettors, point/condenser ignition & manual chokes. All of these needed adjusting: chokes as the engine warmed, points & carburettors as they wore & clogged up. We just accepted all these as being normal. 

Now we just get in, turn a key & the engine runs perfectly from cold every time due to more complex electronic systems. These may be more difficult to fix, but they go wrong far less often & are much less hassle when working properly.

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On 12/02/2020 at 19:49, bigP said:

No, I mean a separate channel out of the circuit breaker, not a dedicated accessory bus.

The Cobalt Digital IP has in-built switching of frog polarity.  So, if you get a short across the frog powered by one, down goes that Cobalt, and anything attached to the same sub-bus.

 

If that ‘sub-bus’ is an accessory bus connected to the command station without circuit protection, we’ll down goes the CS too.

 

Unless of course you try more wiring though switches 4, 5, & 6, or don’t use the Cobalt for switching frog polarity at all, then as you you say, use an accessory bus.  However, if the latter then you need to spend more money on something else to switch those frogs.

 

Paul.

 The Cobalt P Digital requires track power to switch the frog polarity. I have all mine powered by a separate accessory bus using switches 1 and 2. You then use switches 4 and 5 with feeds from the track (or track bus) and switch 6 for the frog polarity. A short occurring (i.e wrongly set point) will only affect the track bus, not the accessory bus, hence the reason why no circuit breaker is needed on the accessory bus.

Edited by MalcT

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26 minutes ago, MalcT said:

 The Cobalt P Digital requires track power to switch the frog polarity.

 

As does any point motor or switch connected to a point tiebar. Even a Peco solenoid with built in switch requires track power to alter the frog polarity.

Or an analog controlled Tortoise or Cobalt requires track power to be switched for electrofrogs.

 

One thing that seems to be oft overlooked - and for that reason adds to the "mystique" of DCC - frog switching is not a unique feature of DCC. 

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7 hours ago, MalcT said:

 The Cobalt P Digital requires track power to switch the frog polarity......

 

Sorry, but no, it does not have to use a track power supply to 4&5 and use 6 to switch frog polarity.

Sure, if you do then an unprotected accessory bus to terminals 1&2 will be fine, as has been mentioned above.

 

I have all mine fed through a sub bus to terminals 1&2, and terminal 3 (which is marked ‘Frog’) powers the frog.  This sub bus goes through a circuit breaker, as a short to the frog would affect the associated sub bus.

 

There are multiple ways to skin the Cobalt cat.

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