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DC Power Bus??

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DC Power Bus??
Posted by Anonymous on Monday, August 15, 2005 3:30 PM
So I am getting close to the point where I will be laying track and wiring feeder lines along my track. I will be running my layout in DC and I'm curious if there is a device that could manage all the wiring, so I don't have to run every feeder back to the power pack. Is this a power bus? or am I confusing terminology with DCC.

Any advice or help would be greatly appreciated, I want to do it right the first time.

Thanks,
Joe
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Posted by Leon Silverman on Monday, August 15, 2005 3:51 PM
It is a power bus. It has no steering wheel but stops at every corner (section of track).
Basically, you run a feeder bus, say 14 or 16 gauge wire underneath your track and run feeder wires (say about 22 ga) to every three foot section of track. This prevents the voltage drop (train slowing) as you get further and further from the power source, particularly if your tracks are not soldered together.
You need only one connection between the bus wire and the power pack, but the bus wire will eliminate the inherent power loss that when the rails are connected by only the rail joiners. The actual contact area between the rail joiners and rails may actually be quite small due to movement and dirt. This creates resistance which causes the voltage drop if the current can travel through only the rails themselves. The feeder wires are soldered to both the bus wire and the rails. This eliminates the voltage dropping resistance of the joiner only path.
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Posted by Anonymous on Tuesday, August 16, 2005 6:14 AM
So I went online and did a search for Power Bus and it doesn't seem to bring much up in the different online stores. Is there a certain specific name for this item? What would be a good brand to get?

Thanks
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  • From: Bedford, MA, USA
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Posted by MisterBeasley on Tuesday, August 16, 2005 7:10 AM
The "Bus" is not a device, it's just the design. All you do is go out and buy some wire - as suggested, 14 guage for the bus, maybe 22 for the feeders.

Think of the way your house is wired. A single cable runs off the circuit breaker panel out through the walls. As it passes each outlet box, it connects up to the outlet and continues on. There's just one connection to the circuit breaker box, just like the Power Bus has just one connection to your power pack / transformer. Then, all the feeders distribute the power to the track.

With DC, you probably will want to use multiple Power Busses. You will need a completely separate bus for every independent loop, yard, wye, turntable, etc., that you want to operate independently, or that you need a separate reverser switch for. (You need separate reverse switches for turntables, reverse loops and wyes, even if you run them off the same speed control.)

DCC greatly simplifies your wiring, but there are still advantages to the multiple Bus structure. For power management, large DCC systems are divided into "power districts" with independent power supplies and circuit breakers, and those switches for reverse loops, turntables and wyes are typically replaced by automatic circuitry. The good news is that a good job of wiring for DC will provide an easy path for DCC if you decide to go that way in the future.

But while I'm at it, please allow me to go a little evangelical on you. I'm a recent convert to DCC. I love it. I had planned on running DC for a while, then gradually changing over and running a dual-mode system for a while, and finally running mostly DCC, with the old DC system still connected for occasional sessions with the old DC locomotives I never got around to converting. Well, after a half-hour running with DCC, I disconnected the DC power pack, and I never looked back. There is really no comparison.

It takes an iron man to play with a toy iron horse. 

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Posted by Medina1128 on Tuesday, August 16, 2005 7:23 AM
The hobby name for what you're looking for is a terminal block or strip. If you visit your LHS (local hobby shop) they should be able to hook you up. If not, try these links:

http://www.walthers.com/exec/productinfo/big/475-TB10
http://www.walthers.com/exec/productinfo/357-1209


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Posted by Anonymous on Tuesday, August 16, 2005 9:37 AM
Thanks for the replies guys, I'm not completely opposed to going to DCC but I figured I'd get there down the road. Those look like exactly what I need Medina, thanks.
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Posted by Anonymous on Tuesday, August 16, 2005 11:12 AM
QUOTE: Originally posted by Medina1128

The hobby name for what you're looking for is a terminal block or strip. If you visit your LHS (local hobby shop) they should be able to hook you up. If not, try these l


These can also be had at Radio Shack, Home Depot, and other similar places. Sometimes they're call 'barrier strips'. Essentially it's a strip of metal with screw terminals on either end all in one block. You can jumper multiple blocks together with wire if you want to make multiple attachment points. This is what I'm doing for my layout. There's a wiring board in the center underneath, and that's where I'm wiring my DCC control circuitry (autoreverser for now, maybe block detection later). Wires run from there to the blocks, so then it's just a simple matter of hooking up the feeders to the connections on the edges. No under table soldering, thankfully!
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Posted by MisterBeasley on Tuesday, August 16, 2005 11:39 AM
You can also order these from Demar Electrronics (www.demarelectronics.com) or Ocean State Electronics (www.oselectronics.com), among others. Demar advertises in MR, but OSE has pictures of everything on their web site.

These places have all kinds of useful things, like toggle switches, wire, LEDs, resistors and other stuff that goes underneath your layout table.

It takes an iron man to play with a toy iron horse. 

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Posted by Medina1128 on Tuesday, August 16, 2005 9:20 PM
Hey, you're more than welcome. That's what the forums are all about!!

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