As will be immediately obvious, I'm at sea when it comes to wiring and electronics.
I'm wiring for DCC and using insulated frog turnouts. I'll be dropping feeders from every turnout and section of track. The feeders will be powered by bus wires--a common arrangement I believe.
1. If I gap the track in my yard per the plan below to prevent shorts between facing turnouts (i.e., not to create a separate power district) and connect the feeders on both sides of the gap to the same bus, do I negate the purpose of the gap? I assume I won't but I'd like to make sure.
2. Is it OK to run feeders from adjacent tracks within the same power district to a common terminal strip in line with that bus? Once again, I assume "yes" as it reduces the number of terminal strips but would like to make sure.
Thanks.
Rick Krall
Since the purpose of the gaps is to separate the track sections electrically running the wires back to common feeder would be like having no gaps at all.
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Rick, the gaps look ok , but I.m having a hard time figuing out where You are talking about hooking the feeder drops to, can You explain this better ?
armchair Rick, the gaps look ok , but I.m having a hard time figuing out where You are talking about hooking the feeder drops to, can You explain this better ?
Sure (he said naively): I'm assuming (1) positive and (1) negative bus wire out from the power source with every positive feeder connected to the positive bus and every negative feeder connected to the negative bus.
I'm trying to wrap my head around whether connecting the track sections on either side of the gap to the same bus would negate the short-prevention purpose of gapping the track. I note that Jeffrey Wimberly said "yes it would--it's as though you didn't have gaps." If that's the case, my next question will be how do I feed every section of track and maintain the benefit of the gaps without creating a separate power district?
I hope I'm not embarrassing myself here....
fkrall armchair Rick, the gaps look ok , but I.m having a hard time figuing out where You are talking about hooking the feeder drops to, can You explain this better ? Sure (he said naively): I'm assuming (1) positive and (1) negative bus wire out from the power source with every positive feeder connected to the positive bus and every negative feeder connected to the negative bus. I'm trying to wrap my head around whether connecting the track sections on either side of the gap to the same bus would negate the short-prevention purpose of gapping the track. I note that Jeffrey Wimberly said "yes it would--it's as though you didn't have gaps." If that's the case, my next question will be how do I feed every section of track and maintain the benefit of the gaps without creating a separate power district? I hope I'm not embarrassing myself here.... Rick Krall
The only reason for "gaps" is for 1-separate power districts, or 2-expansion/contraction joints, or 3 wyes and reversing loops.
Even though I run DCC, I like the idea of separate power districts and I really don't see the reason for power going to loco's that I have no plan on running during a session. Also if by chance I get a short, I can find it much easier by turning off districts until the short clears and then I know where it is.
Hello
The answer of 1 is NO. Think of it - from the bus you send current to different parts of the track. The need for gaps comes with the turnouts. With no gaps you would end up making a full circle of current from the negative bus-> to your track -> through your turnout set to the diverging route and then 'collide' with the current of the other track (positive). Bang - you get a short. Adding gaps and feeders as in your drawing is correct. Almost. For details, take a closer look at http://www.wiringfordcc.com/ , where a lot of wiring, especially handling of turnouts is described in great detail.
And for the record - you are not embarrassing yourself. You just asked a question that a lot of people have but do not dare to send to this forum
After reading on that site, I guess you would like to revise your drawing and add some more gaps, e.g after every frog of each turnout, not only where the turnouts face each other...
And the answer to 2) is also a Yes.
(Edit: Added a revised sample )
Maybe something like this:
OlavM Hello The answer of 1 is NO. Think of it - from the bus you send current to different parts of the track. The need for gaps comes with the turnouts. With no gaps you would end up making a full circle of current from the negative bus-> to your track -> through your turnout set to the diverging route and then 'collide' with the current of the other track (positive). Bang - you get a short. Adding gaps and feeders as in your drawing is correct. Almost. For details, take a closer look at http://www.wiringfordcc.com/ , where a lot of wiring, especially handling of turnouts is described in great detail. And for the record - you are not embarrassing yourself. You just asked a question that a lot of people have but do not dare to send to this forum After reading on that site, I guess you would like to revise your drawing and add some more gaps, e.g after every frog of each turnout, not only where the turnouts face each other... And the answer to 2) is also a Yes.
Oh boy! I gave the wrong information and I am embarrassed. You are so right!
Insulated Frog Turnouts?
If this is true, that you are NOT using "power-routing" turnouts you don't need ANY gaps in your yard.
All Live turnouts have rail A and rail B insulated from each other. In theory you could just wire this yard with two feeder wires going to the buss. IF you use power routing turnouts THEN you would have to insulate any frog-to-frog rail and all feeders would have to be from the point end of the turnout.
What brand and type of turnout are you using?
I'm learning a lot, guys, and I'm grateful.
OlavM--thanks for your reassurance and your illustrated, helpful reply.
gmpullman and David Bedard--To answer your question, I'm using Atlas all-live turnouts, which I do understand shouldn't require gaps, even if frog-to-frog. However--and I think this is critical--Peco 3-way turnouts feed the yard from both ends. When both are set to the straight, no problem. But when I throw one to a diverging route--a short. Perhaps they are at least partially power-routing?
After reading your responses, I isolated the straights and jury-rigged a temporary bus to their feeders. I no longer have a short. I can only assume the 3-ways were somehow causing the problem.
And David, you're absolutely right--I'm sure I'm over-thinking the problem. But I'm learning, however inefficiently, and I appreciate everyone's help in getting me there.
Rick
In looking through the archives I discovered that the problem is indeed the 3-ways--even though they're Insulfrog. davidmbedard put his finger on it in a 2007 thread "Wiring 3-Way Switch For DCC:"
"...The issue is the double frog (back to back....a huge void for small pick-up locos) that serves double duty (can be either polarity, depending on the 2nd set of points)...."
I'll start a new thread to made sure I wire my yard correctly with a 3-way at each end.
RangeroverThe only reason for "gaps" is for 1-separate power districts, or 2-expansion/contraction joints, or 3 wyes and reversing loops.
And powered frogs. If you have powered frogs then you need gaps on the rails leading to the frog.
I have DCC and all my rails are connected to common busses EXCEPT the frog rails which are connected to a switch attached to the throwbar which drives the polarity of the frog. Each frog has a gap in the 4 rails leading to the frog.
Dave H. Painted side goes up. My website : wnbranch.com
YES! If the bus is connected to each of the tracks, there is no seperation between them. This means that you will have to buy a seperate bus for a different section. This is used in power districts (the gaps). If you want to switch off unused locos, use a deat track. You can switch off the track, and no power will go to it (DPDT switch is a good example). If you want it back on, flip a switch to turn that tracks power back on. Using suitcase clips (made by 3M) can help with the splicing and soddering.
Peace
To answer your question directly - no, attaching feeders to the same bus will not negate the purpose of the gaps, provided there are no feeders attached to the bus between the turnout throwbar (lead end of points) and the gaps just beyond the power routing frogs. The point of the gaps is to isolate the section of the turnout that changes polarity when the turnout is thrown. If you install the gaps 3 feet beyond the frog - that's how much track will be power routed. Typically, turnout gaps are put somewhere near the clearance points (where trains would hit if both were approaching the turnout frog from the diverging paths at the same time). On either side of the isolated section of turnout (points to frog rail gaps), it is perfectly acceptable and usually desirable in DCC to link these electrically - which you do by tying to the power bus(s).
If it is desired to feed power to the frog area of the turnout, the frog feeder does not attach directly to the power bus(s), but instead attaches to a contact which changes polarity when the turnout is thrown. The 2 sides of the contact are electrically connected to the power bus(s).
hope this makes sense and helps
Fred W
This is how I would do it. You can connect all the + together on one bus wire, and all the - together on the other bus wire.
Please note I circled two gaps that are NOT needed in red.
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
I'm good, guys; thanks for your great input.