# wiring/power question



## mcn520 (Jan 9, 2013)

I have a 6x12 table with two separate layouts on it. The outer one is just a simple oval taking up the entire 6x12 table, The inner one is a over under taking up the entire 6x12 table using tunnels/trestles etc. i have an 80 watt cw. 
is that enough to power both loops or do i need something bigger ? the loops are separate for now but will most likely be joined with switches eventually but not now. can i power both loops with one transformer or do i need two 80 watts and should i used bus wiring on both loops.
thanks


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## Dave Farquhar (Feb 20, 2013)

Bus wiring will save you wire in the long run, since you'll only need very short feeders to reach the bus, and you can run as many of them as you end up needing. Run really heavy wire--I'm thinking 12 gauge--because you'll get less voltage drop that way. Also keep in mind that multiple transformers can all share the wire connected to the U post, as long as the transformers are in phase (and all modern transformers should ship that way).

The wattage you need really depends on what you're running. Lights chew up wattage faster than anything else. But I wouldn't push a CW80 trying to run two loops with it.

At the very least, I'd pick up something comparable to your CW80 to run the second loop. I ran two loops on an 8x8 table with a 75W transformer on one loop and a 90W transformer on the other for several years before a friend cut me a deal on a postwar ZW. I like the ZW a lot better, but you'll pay much more for a ZW than you will for a couple of sub-100 watt transformers.


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## servoguy (Jul 10, 2010)

I don't know how to use a transformer with a single controller (CW-80) to control two trains. 

If I were doing this, I would bend the rails where the pins are installed so that I only need one feed for each loop. Bending the rails makes a really tight connection minimizing the voltage drop along the track. I have 63 sections of track in a single loop on the floor of my hotel room and I am using only lockon. The trains do slow down a little at the far end of the loop, but not so much as to make me want to run wires all over the floor.


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## gunrunnerjohn (Nov 10, 2010)

Note that if you run command/control or are planning it in the future, you need to consider what you'll be running when planning the wiring. Specifically, MTH DCS (ProtoSound2/3) runs much better with star wiring than buss wiring.


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## Toot_Toot (Dec 3, 2012)

Thanx for that, GRJ. I was advised by my old boyhood train shop to use star wiring whereas Lionel's site videos advise Buss wiring. I was a little confused 'til I read that.


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## gunrunnerjohn (Nov 10, 2010)

Plan ahead, you never know.


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## BigAl56 (Dec 14, 2011)

Please tell us exactly what you wish to run. Do you plan to use Legacy or TMCC? 80 watts is a bit light for running a couple of postwar lighted passenger trains, but for a couple of modern can-motor engines with basic cars it could suffice.


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## gunrunnerjohn (Nov 10, 2010)

Even a single lighted passenger train may strain that transformer.  My full MTH SP Daylight passenger car set draws almost three amps, and that's without a locomotive on the tracks.


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## mcn520 (Jan 9, 2013)

i am planning on running tmcc engines... also can you tell me what star wiring is vs bus.
thanks guys


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## Dave Farquhar (Feb 20, 2013)

Bus wiring is loops of wire under the outside of your train table, and you run short feeder wires from anywhere on the loop up to your track.

Star wiring is running a pair of wires to the center of your table to some kind of a terminal strip, then running wires from the terminal strip out and up to your track.

For smoothest operation, you need a set of feeder wires going to every 3-4 sections of track, regardless of whether you use star or bus wiring.


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## mcn520 (Jan 9, 2013)

ok. that sounds good dave. thank you
any ideas on what kind of terminal strip to get. i'm assuming two wires from transformer to that strip and then wires from that strip to other locations on the track ?


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## sjm9911 (Dec 20, 2012)

I have to echo the others, plan ahead. I have a separate transformer for layout lights, building lights etc. And a zw for my two loops and accessories. My layout is two 4x8 peices of plywood. Not much bigger then yours. I do have a lot of post war accessories and eight or so switches. Remember everything that does something needs power. I found that a little bigger ( for power) can't hurt. If underpowered , not too good. You can always get a bigger and better transformer later but it is best to plan ahead.


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## gunrunnerjohn (Nov 10, 2010)

Any terminal strip will do, the exact type is not critical. See what you can scrounge up surplus and cheap.


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## mcn520 (Jan 9, 2013)

thanks again guys
appreciate the help.....


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## BigAl56 (Dec 14, 2011)

If everything you run is TMCC then you only need a single transformer or power supply to keep the track at a constant 18v. You can pick up a nice rebuilt Lionel KW transformer with plenty of power for two trains and accessories for not too much on eBay.

Bus wiring is good for Lionel Legacy or TMCC. If you are going to run MTH DCS then you will need to utilize star wiring.


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## mcn520 (Jan 9, 2013)

ok i did what you suggested and bought a kw transformer on ebay to run both loops of track and two trains.
Now how do i wire command so that i can control both loops with one command base... 
keeping in mind that those loops are currently separate and not joined together by switches.


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## gunrunnerjohn (Nov 10, 2010)

What command system are we talking about? For TMCC, you'll simply wire the outside tracks common and connect the TMCC/Legacy command base signal pin to the common connection. For DCS (MTH ProtoSound), you'll connect each loop to a channel on the TIU.


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## mcn520 (Jan 9, 2013)

i'm running tmcc and i know i connect both outside tracks to each u post on the kw but the tmcc base do i run a wire to each of those u posts or just one wire to one of the u posts ?


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## engelphotos (Nov 22, 2011)

Question ?

Regarding the spacing of feeder wires, Depending on track size(length) again assuming 3-4 sections of track equals 30-40 inches, is that over doing it about, I was under the impression every 5-6 feet was sufficient. I ran a bus system since at the time i had never heard of the star system.


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## Dave Farquhar (Feb 20, 2013)

If you're able to get by with feeder wires every 5-6 feet without voltage drop, then you're fine. Track joints cause voltage to drop faster than distance does, generally, so I go by track joints more so than by distance.


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## engelphotos (Nov 22, 2011)

Yes I can see where as the distance from the source of voltage increases, increasing joint's would decrease the voltage along the distance in question. I've just recently replaced my main loop and siding with Atlas O three rail nickel/silver track. I had O gauge Lionel tubular track. Although i can't see any performance difference as it relates to the actual train performance, this track is more prototypical and pleasing to the eye. On my siding where i didn't put a extra power source i can see the train will slow down. I need to just add a rail joiner lead's for power their. Overall I used 12g. for the bus and 16g. for feeders. I'll have to do a check with my meter and see if there any measurable drop of voltage.


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## sjm9911 (Dec 20, 2012)

You guys had me scared for a bit. I only have 2 lockons on each of my two loops. All of my switches are separately powered. I never noticed a voltage drop. So I just tested the loops with a meter. No lost voltage through 40 peices of track ( give or take ) on each loop. Did I just get lucky?


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## engelphotos (Nov 22, 2011)

I don't have an engineering degree and only have a better than basic understanding of the subject matter, with that out of the way No you didn't get lucky.

As you saw what we where discussing, Voltage drops as their are more chances to loss conductivity along a set connections. I'm not sure if you have as a ex. 17 volt's and you happen to be using 12g wire, at what distance would you start to see a voltage drop but, as the connections increase from the point of contact theoretically there is voltage loss. Typically the cause of voltage loss is because of the type of connection. Older track with dirty pins has less conductivity then new track with new pins. As time goes by the track will begin to oxidize and loss it's conductivity at the rail joint. I believe some folks will solder jumper wires from one track to another adjoining track to prevent this from occurring. Since I replaced my track for only the appearance reason although, I think the rail joining aspect is superior than conventional tubular track. I have 14 sections of track between feeder wires with no voltage drop. At some point if the voltage does start to drop I believe my first step would be to start putting in jumpers between rail connections. I do have voltage drop right now after a turn-out and will have to go back and double check all my joints for connectivity. I wonder if you have installed a "fuse" in line with your feeders. I currently have a 180 watt Lionel Powerhouse, powering the track itself and wonder if anyone has incorporated any additional safe guards. The Legacy Engines don't like short's and i'm concerned about the boards in these loco's

Fred


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## gunrunnerjohn (Nov 10, 2010)

mcn520 said:


> i'm running tmcc and i know i connect both outside tracks to each u post on the kw but the tmcc base do i run a wire to each of those u posts or just one wire to one of the u posts ?


Since the two U posts on the KW are internally connected, one is sufficient.


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## mcn520 (Jan 9, 2013)

thanks john. everyone else got carried away with voltage drops !


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## T-Man (May 16, 2008)

servoguy said:


> I don't know how to use a transformer with a single controller (CW-80) to control two trains.
> 
> If I were doing this, I would bend the rails where the pins are installed so that I only need one feed for each loop. Bending the rails makes a really tight connection minimizing the voltage drop along the track. I have 63 sections of track in a single loop on the floor of my hotel room and I am using only lockon. The trains do slow down a little at the far end of the loop, but not so much as to make me want to run wires all over the floor.


That is easy. Have one train forward and the other with a working e unit. SHut the power before a colision to revesre the reversible train.! The reversible train should be faster.:thumbsup:


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## engelphotos (Nov 22, 2011)

Sorry didn't mean to get on a tangent and hijack the thread !!


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## servoguy (Jul 10, 2010)

T, I might just try that.


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## T-Man (May 16, 2008)

That was just the other day and I thought "Gee nobody ever mentioned running two trains on a track like this." Remmenber the road game with cars? Chicken? It is sorta like that.


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## BigAl56 (Dec 14, 2011)

If you have the March issue of CTT they have a good wiring diagram that shows all the wiring and how to do it.

I recommend 14 gage stranded wire. Crimp a circle connector on the end of a black wire and connect to the U terminal on the ZW. You will only need to run one wire. Tie this wire to a Black bus wire running the length of the layout. Connect the wire from the TMCC base unit to this U bus. Pick up a package of blue tap splices, (suitcase connectors), from the hardware stores and simply crimp all your outside rail feeds to this U bus.


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## mcn520 (Jan 9, 2013)

one more question i guess. do i need any other circuit protection for the tmcc locomotives if i am using the kw transformer.... a direct lockon ?


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## gunrunnerjohn (Nov 10, 2010)

You do most certainly want some circuit protection. The TMCC Direct Lockon will work, note that it will NOT allow conventional operation in the circuit, it's strictly designed for steady voltage, and will drop out at around 12 volts.

You can use a fuse of modern fast acting circuit breaker in the track power connection for each track.


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## BigAl56 (Dec 14, 2011)

I would try to wire in a 7 amp breaker in series with the power to the track.


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## mcn520 (Jan 9, 2013)

ok. i've ordered two 10amp breakers from train electrics to put in between wiring on each loop instead of the tmcc lockon.'
due to not reading too many good things about the lockon.
i am using a 16awg bus wire around the loops.
hopefully this all works out.
thanks for the help guys


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## Big Mike (Dec 2, 2011)

gunrunnerjohn said:


> Note that if you run command/control or are planning it in the future, you need to consider what you'll be running when planning the wiring. Specifically, MTH DCS (ProtoSound2/3) runs much better with star wiring than buss wiring.


 
YEP,I learned this the hard way!. ............. Mike


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## gunrunnerjohn (Nov 10, 2010)

Thus the warning, we're learning that right now on the modular club layout. DCS doesn't run well at all, TMCC runs fine. I'm crawling under tables and trying to make it better!


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## servoguy (Jul 10, 2010)

It would be interesting to know why one system works and the other doesn't. I would be in real trouble with my single feed to a large layout.


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## servoguy (Jul 10, 2010)

It would probably help to have a way to measure the field strength so you know when you are making things better.


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## servoguy (Jul 10, 2010)

What frequency is the carrier?


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## gunrunnerjohn (Nov 10, 2010)

TMCC is 455khz, DCS is 3.27mhz. More importantly, TMCC uses the outside rails as a giant radiator and the power line ground (earth ground) as the other side of the signal. DCS uses the outside and center rails as a transmission line, thus it's much greater sensitivity to wiring practices.


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## servoguy (Jul 10, 2010)

TMC is just below the AM band. The track then becomes sort of a large loop antenna. 

At 3.27 MHz, one has to watch out for bad VSWR, etc. More difficult.


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## gunrunnerjohn (Nov 10, 2010)

Well, TMCC also doesn't rely on the track to be a transmission line, which is the major issue with DCS wiring. The wavelength of the 455khz signal is 2162 feet, so VSWR isn't much of an issue.

The wavelength of 3.27mhz is 301 feet, so wiring and track can easily reach at least 1/4 wavelength or more. Add to that that they're actually treating the wiring as a transmission line to broadcast the signal, and you have the recipe for problems without following the DCS wiring guidelines.


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## servoguy (Jul 10, 2010)

I agree completely. It is hard to create much of an antenna pattern at short distances at 455 kHz.


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## mcn520 (Jan 9, 2013)

ok so wiring the lockon is confusing.... do I just need the one power adaptor cable to connect the lockon to the kw.. or do I also need to wire the lockon to the fastrack also... it doesn't seem so since the same wires on the terminal track go to the same connections on the transformer as the power adaptor cable would...


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## gunrunnerjohn (Nov 10, 2010)

WOW, that was confusing, no wonder you are having problems. 

You're wiring a KW to the TMCC Direct Lockon, right?

You need a fast acting 10A circuit breaker or fuse between the KW and the TMCC Direct Lockon, as the KW doesn't have much of a circuit breaker.

Next, you wire the KW A and U (or B and U) terminals to the inputs of the Lockon, the U terminal goes to the outside rail connection. Since the input to the unit is a Molex connector, you use the adapter cable for that. You wire the outputs of the lockon to the track.

In the following illustration, the KW replaces the Powerhouse transformer.


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