# Lionel ZW transformer shorting issue



## buzzvictor (Dec 21, 2011)

I have two ZW's running my layout. One works perfectly. The other will operate for a minute or so and then begins a routine of shorting out, maintaining the shorted state for a few seconds, resetting itself, running for a few seconds and then shorting again. I have interchanged the two transformers and the problem persists no matter which portion of the layout the faulty unit is connected to. Any ideas for a repair? Thanks.


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## BigAl56 (Dec 14, 2011)

Are the two transformers properly phased? You should be able to tie matching thermals between the two and operate both without shorting. Try rotating the plug on the bad transformer 180 degrees to be sure.


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## buzzvictor (Dec 21, 2011)

I believe that they are in phase, but I will check to be sure tonight. I appreciate your thoughts and will post the results of my efforts.


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## T-Man (May 16, 2008)

They only have one circuit breaker. It's bad or the unit is overloaded. Unless you have a bare wire somplace. Time to take the case off. All the good info is here. Does it have a problem without any connections?


Olsen library ZW manual


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## servoguy (Jul 10, 2010)

It sounds like a faulty circuit breaker. Does it have the problem when it is disconnected from the layout?

You don't have the two transformers wired so that the outputs are connected, do you? Bob Nelson would holler at you.

If the overload light goes on, it doesn't necessarily mean the transformer is overloaded. If the circuit breaker is defective, it may trip at a low current.


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## buzzvictor (Dec 21, 2011)

It does not happen when there is nothing connected. I have removed the case. I don't see anytjing that, to my very unpracticed eye, looks out of place. Believing the circuit breaker to be that small component that opens and closes much like the contacts on a relay, I have cleaned the contacts to no avail. Perhaps I should attempt to switch the two circuit breakers and see if the problem migrates from the faulty transformer to the other. Your thoughts?


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## T-Man (May 16, 2008)

How do the wheels look? The carbon rollers.

The old fashion disc for the whistle also fail too.

Pull the bulb out first. The red one.


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## servoguy (Jul 10, 2010)

I assume the red light is coming on? If it is, the circuit breaker is definitely tripping.

Put a load on the transformer, like a loco, and look at the circuit breaker. If the red light comes on, you should see an arc inside the circuit breaker contacts. Some of the circuit breakers are adjustable, but the procedure for adjusting them is not trivial, and should probably only be done by an experienced technician or electrical engineer.


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## gunrunnerjohn (Nov 10, 2010)

Measure the current draw with a light load, then start increasing the load until the breaker trips. I keep a bunch of 8 ohm 75W resistors around for loads, great for testing and repairing transformers.


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## buzzvictor (Dec 21, 2011)

Thank you all for your input and suggestions. I disconnected the circuit breaker in the faulty transformer and replaced it with the breaker from the working unit. Sure enough, the faulty transformer functioned perfectly. I have ordered a replacement breaker ($9.50) on line and should be fully functional before the new year, maybe by Christmas. I wish you all a Merry Christmas and Happy New Year.


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## servoguy (Jul 10, 2010)

If you want to get the transformer going quickly, you could replace the original circuit breaker with an automatic resetting automotive breaker of 15 amps. Then if you want to really do it right, add a 5 or 7 amp automotive breaker to each of the 4 outputs. Then you protect the transformer as well as the wiring.


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