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feeder wires

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feeder wires
Posted by loosecaboose73 on Saturday, January 06, 2018 8:59 PM

I am building a small layout, 4'10" X 8', DCC. I want to use feeder wires to avoid loss of current. Question, One end has to be connected to the power source, but what about the other end? Should they be capped?  Or should they be a loop just like the track? I keep looking and it never says one way or the other.

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Posted by 7j43k on Monday, January 08, 2018 11:34 AM

Just to be clear, I think you're talking about running a pair of wires, sort of underneath and paralleling the track.  And tapping off of those up to the track.

The wires should be "capped" to the extent that it's not good to have bare powered conductors out in the open.  You may rightly point out that that is exactly the case for most of the layout, above.  But, in this case, the problem is that there COULD be an accidental contact and then you'd have to troubleshoot it to track it down.  If it's "capped", it's tough to get that accidental contact.

I think you'r asking what happens if you've got something like  loop of track.  You start out somewhere under the track, and start stringing wire.  What do you do when you get around the track and come close to where you started?

You can do EITHER.  You can stop short with your run, at the last track feeder drop. Or you can continue on, and connect your feeder wires back to where you started.

IF you choose the latter, when you do that "connecting back where you started", there's two ways you can connect:  the right way, and the wrong way.  With the wrong way, you'll short the power supply.  This will be a signal to switch the connections.  Then you should not have a short.  There's fancier ways to do it, but this way will work.

The other thing is that, since you're feeding your track from BOTH directions, you'll have half the resistance in the wire.  That's a good thing.  And all it takes is going just a little bit farther.

 

I don't think it matters mightily which you choose.  Myself, growing up in the electrical construction trade, I probably wouldn't "finish" the loop, 'cause it just feels weird.

 

It could, can, and perhaps will be argued that DCC is a different case.  What with the signal being overlaid onto the power.  Might be true.  But.  I also believe and suspect (though can't PROVE) that all that will happen is that your trains will run "funny".  Which will then tell you that your experiment didn't work.

Of course, it would be better if someone ELSE did that experiment.  Perhaps someone who has will drop a line.

 

Ed

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Posted by selector on Monday, January 08, 2018 11:39 AM

Larger layouts need a thick 'bus' wire that doesn't encourage large drops of voltage over distance.  At suitable intervals, you pare back the insulation on those stouter wires and solder one end of a feeder wire.  The other end of the feedeer supplies the rails with half the 'voltage'.

Short track systems, like yours, just need one or maybe two pairs of 'feeder' wires between the output terminals and the rails.  So, no capping!  Capping is for the ends of a bus wire that doesn't loop back to the source.  The 'feeders', the thin wires, go from the base unit's outputs, rail A and rail B, and up to connect to the two rails, A and B.  Make sure, if you have two sets of feeders, that the same terminal wires go to the same rail, A or B.  Don't mix them up!!

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Posted by loosecaboose73 on Monday, January 08, 2018 11:44 AM

Thanks, I think I will just cap them. Sorry I had the trems turned around.

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Posted by loosecaboose73 on Monday, January 08, 2018 11:45 AM

Thanks!

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Posted by 7j43k on Monday, January 08, 2018 11:59 AM

selector

So, no capping!  Capping is for the ends of a bus wire that doesn't loop back to the source.

 

Please define "capping".  My version is very close to a wire nut screwed onto the end of a wire.

 

Ed

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Posted by selector on Monday, January 08, 2018 2:46 PM

It's a great question, Ed, and I took his statement to mean he was mixing his terms up a bit and needed some orientation.  For example, he hadn't used the term 'bus', about the only thing I would 'cap'.  Instead, he used 'feeder', which one wouldn't cap at all. The other end must be somehow made to make contact with part of a rail somewhere...or a 'feeder' it ain't.

Also, I wondered if he meant 'snubber', but I didn't want to reach out that far just yet.

-Crandell

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Posted by BATMAN on Monday, January 08, 2018 3:02 PM

Allen Gartner says that for the best performance "everything should be soldered to something".

http://www.wiringfordcc.com/ 

I followed this advice and have never had a wiring issue.

As far as the end of the Bus wire goes, I just wire my last set of feeders to the end of the Bus, so there is nothing to cap.

 

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1

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Posted by loosecaboose73 on Monday, January 08, 2018 3:10 PM

Thanks to all, I been away from the hobby way too long (about 30 years). Employment at the U.P. got in the way plus coming home from working on the railroad to a model railroad was too much like a mail man going for a walk on his day off. It has really changed, and your answers to my question are really helpful. Now before I wire it, I must correct a track work mistake. Glad I'm retired!

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  • From: North Dakota
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Posted by BroadwayLion on Tuesday, January 09, 2018 11:10 AM

Some network systems need to be capped. These will be ones that use coaxial cable. (TV cables etc) These are capped with a resistor that absorbs the signals at the end of the wire, otherwise they would reflect baack across the cable and cause trouble.

 

Old 300 ohm TV wires had the same problem. You could not leave a wire in a spare room for an additional TV set if it was not connected. You would get ghosts on the screen. This was corrected by disconnecting the extension.

 

So there are many different application, and some DCC systems might be an issue with them. That information you will find in the package with your DCC System.

LION uses DC and has open bare bus wires. I can solder them anywhere I like. There is no need to cap the wires or to loop them back. In any event looping them back can have issues of its own even thoug the tracks do just that.

 

Oh well, the more details the better the answer, otherwise a LION might sneak in andy try to make pretzels out of sawdust.

 

ROAR

The Route of the Broadway Lion The Largest Subway Layout in North Dakota.

Here there be cats.                                LIONS with CAMERAS

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Posted by 7j43k on Tuesday, January 09, 2018 1:02 PM

I've been to a number of Free-mo setups (Free-mo is DCC).  The "ends" of the buses are rarely "capped".  They.  Just.  Stop.

I've been to a presentation that proposed an electronic end, similar to what Lion describes, as being a great and wonderful thing.  It may be.  But I've yet to see the need for this thing.  If I do, I'll install it.

 

Ed

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Posted by loosecaboose73 on Tuesday, January 09, 2018 1:40 PM

That one is very helpful Ed. Thanks.

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