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track buss install?

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  • Member since
    October 2005
  • From: Ulster Co. NY
  • 1,464 posts
Posted by larak on Friday, July 17, 2009 9:53 PM

maxman
I have a question regarding bus length.  If the layout is 24 feet long, how do you arrive at a 50 foot bus?  I thought that the bus length was from the booster to the end point.  Is the correct method to double this distance?

 

Technically, no. The length is the length.  But that is misleading because the current has to flow out through one wire and back in through the other. The actual wire (and electron path) length is twice the bus length plus twice the nearest feeder length. This ignores the fact that the rails also carry come current.

Karl

The mind is like a parachute. It works better when it's open.  www.stremy.net

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  • From: East central Missouri
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Posted by Santa Fe all the way! on Friday, July 17, 2009 5:19 PM

mfm, sounds like you know your electric theory. Im in my electrical phase in school right now. Im using 12ga wire for the buss and 20ga for the feeders. I've got a 80' shelf layout.

Come on CMW, make a '41-'46 Chevy school bus!
  • Member since
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Posted by mfm37 on Friday, July 17, 2009 4:23 PM

 Voltage drop is a product of length and wire size. Total bus length is out and back. So 40 feet one way is 80 feet of wire. There's a drop at 1 foot that's all but impossible to measure with our average meters. The drop increases as the length increases but can be reduced by a larger wire size. It can never be eliminated because wire and track is a resistor. What can't be substantially increased is the size rail. Use a large enough bus and add as many feeders as possible. Bus size and length is the most important factor as the feeders and rail are parallel resistors and the total resistance in a parallel circuit will never be more than the resistor with the lowest value (the bus).

  • Member since
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  • From: 4610 Metre's North of the Fortyninth on the left coast of Canada
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Posted by BATMAN on Friday, July 17, 2009 3:03 PM

 My layout is dogbone shape bent in a U. Its footprint is 24' x 15' so my power is at the bottom of the U with Bus wires going out like many fingers up each side. I would say my longest bus is about 30' or so. So far it works great.

 

                                                             Brent

Brent

"All of the world's problems are the result of the difference between how we think and how the world works."

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Posted by maxman on Friday, July 17, 2009 2:20 PM

spearo

My layout is 24' long so in order to avoid a 50' plus bus I put the booster in the middle.  The busses are still upwards of 35' in some places but as long as you use the correct gauge wire it is not a problem.

I have a question regarding bus length.  If the layout is 24 feet long, how do you arrive at a 50 foot bus?  I thought that the bus length was from the booster to the end point.  Is the correct method to double this distance?

  • Member since
    August 2004
  • From: Amish country Tenn.
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Posted by loathar on Friday, July 17, 2009 11:40 AM

I've got about a 40' buss and put it in the middle. I think you only have to worry about voltage drop when your talking 100'+
On a side note, I use 20 gauge solid wire form my feeders and I'm starting to regret it. Should have gone with stranded. I've had to fix two already where they broke.

  • Member since
    December 2004
  • 106 posts
Posted by spearo on Friday, July 17, 2009 10:14 AM

My layout is 24' long so in order to avoid a 50' plus bus I put the booster in the middle.  The busses are still upwards of 35' in some places but as long as you use the correct gauge wire it is not a problem.

  • Member since
    February 2006
  • From: Gahanna, Ohio
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Posted by jbinkley60 on Saturday, July 11, 2009 8:25 PM

mmr1229

when installing the buss wires for the track does it matter where the booster wires make there connection? should the connection be in the middle of the buss or can it be at either end and not matter?

Many folks will tell you the middle, in order to get the least voltage drop at the end.  If the bus is not extremely long, it really won't make a big difference if you connect in the moddle or near an end.

 

Engineer Jeff NS Nut
Visit my layout at: http://www.thebinks.com/trains/

  • Member since
    February 2002
  • From: Westchester NY
  • 1,747 posts
Posted by retsignalmtr on Saturday, July 11, 2009 8:04 PM

I have a digitrax system and the power buss directions recommend not having a continious loop so I placed the booster near where I have the beginning of the buss. It is also near the spot where the buss ends but is not connected end to end. The rail is also gapped at that spot too.

  • Member since
    March 2009
  • From: Harford County, Maryland
  • 86 posts
track buss install?
Posted by mmr1229 on Saturday, July 11, 2009 7:27 PM

when installing the buss wires for the track does it matter where the booster wires make there connection? should the connection be in the middle of the buss or can it be at either end and not matter?

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