# restoring a transformer.



## watchunglava (Jan 12, 2010)

what are things i should do to make an old transformer safe and efficiant . obiously change the 2 prong cord to a 3 prong but what else?


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## Reckers (Oct 11, 2009)

I'd say replacing the cord is the biggest issue. You can also open the case, blow out the 40-or-so years of accumulated dust and such. Examine the wires inside for crumbling insulation and replace whatever needs it. Adding an off/on switch to the cord is a nice improvement; saves you from tugging it out of the wall as you work on something.
If you're starting a new layout, the safety-nazis will tell you to install and plug it into a GFI outlet. To me, that's overkill---I mention it because I'm not always right and you might want to.

Post Script: be dubious about using it at all if there's a lot of rust inside. Rust = water at some point in the past = failed insulation on the coil.


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## T-Man (May 16, 2008)

You don't need three prongs. Modern ones don't have them but you have to have them in phase. (Big prong little prong). You can install a modern circuit breaker but I cannot help with a specific manufacturer. These are toys so the low voltages are deemed safe. Best thing is to change out dried and cracked wiring. I have a prewar transformer whose wiring is in a block of PCBs. I don't use it. In some cases you may have to upgrade your DC output. Some are good others are not worth it. Still others have parts that need a changeout. Whatcha got?

I use an outlet strip. and I do paint metal surfaces to prohibit rust. Most of the time the cord change soes the trick.


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## Reckers (Oct 11, 2009)

T-Man, what do you think about the circuit-breakers on power strips?


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## T-Man (May 16, 2008)

I don't think all of them have them. Anyway the purpose for the transformer is to protect the train when it derails. You need the power shut. Having a good circiut breaker designed for track surges is a good idea. If you have a big ZW or four of them You usually see them( circuit breakers).


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## Big Ed (Jun 16, 2009)

watchunglava said:


> what are things i should do to make an old transformer safe and efficiant . obiously change the 2 prong cord to a 3 prong but what else?



May I ask what transformer do you want to make "safe and efficient"?


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## jimtone (Nov 11, 2014)

*transformer cord replacement*

I've got a #309 that looks good but the cord is "toast" from sitting in the Louisiana attic for more than 40 years. I'm wanting to know if anyone has photo documented the replacement of the power cord on one of the small 25 watt #309 or 319 transformers? I also read that I should be sure not to reverse polarity when changing the cord but these originals didn't have cords with polarity direction/preference. My concern is what does the inside of these smaller transformers look like and what to expect? I'm new and perhaps not savy enough to search this out? Help! Thanks!


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## Mark R. (Jan 26, 2013)

jimtone said:


> I've got a #309 that looks good but the cord is "toast" from sitting in the Louisiana attic for more than 40 years. I'm wanting to know if anyone has photo documented the replacement of the power cord on one of the small 25 watt #309 or 319 transformers? I also read that I should be sure not to reverse polarity when changing the cord but these originals didn't have cords with polarity direction/preference. My concern is what does the inside of these smaller transformers look like and what to expect? I'm new and perhaps not savy enough to search this out? Help! Thanks!


If the power cord is toast, chances are pretty good the inside wiring wouldn't have faired much better. I've opened up old transformers and the wiring was so dry and brittle, all the insulation crumbled right off the wires when I moved them about.

Also check the windings on the transformer itself to make sure the enamel on the windings hasn't deteriorated as well.

Mark.


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