# Transfomer question



## Davidfd85 (Jul 4, 2011)

I hope someone can answer this before I make a big mistake. 
I'm using the AC connections from a Life-Like set to run power to all my turnouts/switches but its not marked + or - on the terminals. For some reason I think the + is always on the left but not sure and don't want to run all my wires and have it back wards. 
If anyone knows it would help a bunch.

Thanks


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## Artieiii (Apr 25, 2011)

It's not marked + or - cause it's alternating current. Plus changes to minus 60 times per second. 
-Art


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## Big Ed (Jun 16, 2009)

Artieiii said:


> It's not marked + or - cause it's alternating current. Plus changes to minus 60 times per second.
> -Art


I was told once that it doesn't matter which way you hook the wires up with AC, as it will work either way.

Someone correct me if I am wrong.


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## gunrunnerjohn (Nov 10, 2010)

Unless you're using it on the tracks, or have one side common, you can connect it either way. The only thing that is polarity sensitive on an AC transformer is the whistle/bell controls, they put a DC offset on the tracks.


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## Davidfd85 (Jul 4, 2011)

Thanks Guys,
They are Atlas turnouts and they are AC. I think what got me confused is the wiring diagram I found for the control panel I'm making. It shows AC power source with + from it to the center of the SPDT switches and - to the ground side of the turnout. Then looking at the transformer there were no markings so got concerned and thinking to much I guess.
That and I guess I've just been working on cars and street rods for so long it didn't click.


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## gunrunnerjohn (Nov 10, 2010)

Can't over-think these things.


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## Nolan (Aug 4, 2011)

While D.C. has a defined positive (+) and negative (-) connection transformer output A.C. doesn't really care which wire is which. Some times diagrams will show a neutral or ground connection as white and a power or hot connection as black. This is only relevant when wiring A.C. from a power drop (house wiring) because your are connected directly to the power grid. When wiring from a transformer either terminal can be considered as ground and the other as hot because the transformer isolate the circuit from the power grid.


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## tjcruiser (Jan 10, 2010)

A bit off-topic to the original post, but the exception to the post directly above is when using two AC transformers to power track blocks in a traditional layout (as in AC O-gauge). If the blocks can be connected via a turnout, I think it's important that the phasing of both transformers is the same. I.e., you don't want the sine waves to cancel each other. Easy fix if that's the case ... flip the plug around on the transformer at the wall socket.

(I probably have the details a bit convoluted here, so I hope you electrical gurus chime in with whatever I've mixed up ...)

TJ


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## Reckers (Oct 11, 2009)

Teej, you have it correctly.

David, first of all, welcome to the forum! Now, about that AC transformer. As everyone else pointed out, for most applications, you can use either wire for + and for -; it just doesn't matter. This is because the current flow reverses itself 60 times per second, so once the motor that drives your turnout is in motion, the motor's inertia takes over and keeps it moving in the same direction as the power pulses into the wiring. Your better AC transformers actually have three posts: one is the ground, one is a constant-voltage AC, and the third is variable-voltage AC. The ground's purpose is obvious; the constant-voltage post is used for wiring your accessories and the variable post is for your track. This enables you to keep constant power to accessories while you accelerate and decelerate your train.
As TJ pointed out, you can also use multiple ac transformers on the same track, but if they aren't in phase, bad things happen: I have a Lionel doorstop that used to be a tranny. Further, you can run AC trains on AC or DC tracks, but if you try to run your DC train on an AC track, there's gonna be a second doorstop.

Best wishes,


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## Davidfd85 (Jul 4, 2011)

Thanks guys for all the information. 
With this being my first layout there is allot to learn I know. I might have done somethings alittle back wards. I got the DCC up and working, got all the track soldered except the switches just in case of problems or change out. Today is wire the turnouts day, all 11 of them. I have the color code for the wiring worked out already, transformer mounted under the table and 2 bus bars setup to handle the power distribution for each switch. Even left a few extra connections for expansion in the future. I'll try to post a couple of pictures later. 

Thanks again.

Well got them all wired and tested with a loco and couple of cars. Nothing smoked or threw sparks so must have done something right. Still need to make it a bit neater with the wires then I'll post a couple of pictures.


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