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Two tranformers, one train

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  • Member since
    December 2001
  • From: Austin, TX
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Posted by lionelsoni on Saturday, December 29, 2012 1:50 PM

Running between tracks powered by different transformers and especially between tracks powered by different outputs from the same transformer is not really safe.  Unless the two tracks are set to almost exactly the same voltage, a fault current flows when the train connects them together by passing over the insulated gaps.  If the the two tracks are powered by different transformers, the interruption of the fault current as the wheels or pickups pass the gap can produce an inductive voltage spike of hundreds of volts, which may be fatal to a modern electronics-intensive train.  If the tracks are powered by different outputs of the same transformer, like a ZW or Z, there is no protection from the transformer's internal circuit breaker, and very high currents are possible.  If the train stalls over the gap, the current can burn out the transformer and even 14 AWG layout wiring which would be adequate for a ZW transformer.

Having the transformer outputs in phase makes it possible to match the voltages, but is no guarantee that they are actually matched.

Bob Nelson

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Posted by jgryguc on Friday, December 28, 2012 4:10 PM

Thanks Nick.  I've already marked them.  I appreciate your help.

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Posted by nickaix on Friday, December 28, 2012 3:27 PM

Now, before you forget, paint the top side of each plug with some white-out so you will always know which way goes up Smile

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Posted by jgryguc on Friday, December 28, 2012 12:28 PM

YES!!!!   Brilliant!!

I cant' believe it was so simple and that I didn't think of it before.  Thank you so much Jeffrey.

Jerry Gryguc

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  • From: Orig: Tyler Texas. Lived in seven countries, now live in Sundown, Louisiana
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Posted by jeffrey-wimberly on Friday, December 28, 2012 11:58 AM

Could your transformers be out of phase? Unplug one from the wall and rotate the plug 180 degrees and plug it back in.

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  • Member since
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Two tranformers, one train
Posted by jgryguc on Friday, December 28, 2012 11:48 AM

I have a large O guage layout, but it's narrow.  I can run two lines off a ZW in one room, and two more off another ZW in another room.  The lines are insulated against each other with fiber pins so I can run four engines at once, with independent control of each.

The only thing I can't seem to get is running from one side of the layout into the other without the train stopping as it switches from one track power to the other.  I know it can be done.  when I first set this up it worked ok.  Not sure what I did wrong. 

Can someone help me? 

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