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Everyone,
I'm new to MRR and have a 4x8 woodland scenics layout with about 40' of track and only a single power feed coming up through the base and currently not seeing any problems.
I've been reading you should run power feeds ever 3-6' of track
My question is if I run multiple feeders from my Digitrax Zephyr do you need to insulate each section of track for each power feed from the same DCC unit?
I know you have to keep the polarity match to each rail, just wondering if running two feeders to a single rail without using an insulating connector will cause a problem?
I have a 4x8 woodland scenics layout with about 40' of track and only a single power feed coming up through the base and currently not seeing any problems.
No, that would be defeating the purpose of having multiple feeders.
I know you have to keep the polarity match to each rail, just wondering if running two feeders to a single rail without using an insulating connector will cause a problem?
No, the opposite. The rail is actually one "wire". The more wires there are to carry the current to the loco the better. Breaking a rail wire with an insulated joiner or gap would be breaking one of the wires.
If a short circuit anywhere on the layout causes the DCC system to trip its circuit breaker then every thing is OK and more feeders aren't needed. If the circuit breaker doesn't trip then more feeders are needed.
Here is what I would do with a 4x8 layout. I would run three more sets of feeders equal distance through the mainline. If it is truly a 40' mainline then there would be one set of feeders every 10 feet. The train would never be more than 5' from a set. On a 4x8 there is no need for a bus to run along under the rails. It just isn't worth the cost and hassle to do that.
First, the only real test of the sufficiency of power feed to the whole rail system is to do what are called 'quarter' tests in about five or six random places. Literally, you place a quarter on the rails so that the coin touches both rails concurrently. If there is a short indication and power to the rails stops, your short circuit detector is getting enough voltage with embedded DCC signal. If one of the quarter tests doesn't force the base unit to shut off power to the rails, then it is one of two things...a dirty/corroded/splayed joiner that is not passing current well, or it isn't getting enough power from the single pair of feeders at that location. Another pair of feeders there would solve the problem, ideally by soldering a new joiner there and the feeders to it. I'd bet that pair of feeders cures any deficiencies in voltage UNLESS other joiners are failing.
Raising the point that sliding joiners can get crud in them to the point where they just don't transmit current any more. Finding the bad ones can be a chore.
Rail compared to copper wire is a poorer conductor of electricity. Add in loose rail joiners and it gets worse. That is why there is a recommendation for multiple feeds every so many feet of rail. If you are using 3' long sections of flex track versus 3 1' long sectional pieces, the number of joiners drop and you could use less feeders.
Sounds like your current setup is fairly good. I too would recommend the quarter test on the rails furthest from your feeder connection. If things work there, every place else should be better.
The point of having multiple feeders is to lessen the chance of a dead section of track. That will usually happen when you have guests over to see your work. I'm running feeders to every section of track on the D&J Railroad. That's over 700 solder joints.
