There is a way to test the TVSs. You need two transformers, a power resistor, and an oscilloscope. Put the two transformers in series so the maximum voltage from one to the other is the sum of the out voltages of each one. Remove all of the electronics, such as locos and tenders and anything that has a TVS in it. Put the 100 ohm power resitor in series with the transformers. Then put the resistor and the other output of the transformers across the Lockon. With the scope, look at the waveform across the lockon. It should show clipping at about 30 volts. Now, if you have several TVSs you won’t know if all of them are working. To test each one, you would have to separate them somehow. Don’t test a loco or any electronics with a TVS this way.
Thank you Rob.
I just got a postwar ZW with a bad breaker. Is a 15 amp automotive breaker the right choice to replace it? 'Cos I just put in a Littelfuse 15 amp breaker, and the durned thing practically arc welds without popping…
Mitch
To paraphrase Lionel: The ZW’s internal circuit breaker is designed to protect the transformer.
It’s trip point is too high to protect commonly used wiring or much of anything else. Many people use smaller external breakers to provide a lower trip point for individual transformer outputs. I like to put one on each of the “Hot” terminal posts, “A” through “D”.
I use Lionel Postwar #91 electromagnetic, adjustable circuit breakers. When properly adjusted they will trip instantly on a short.
There are many other options.
Does it ever trip? If so, how long does it actually take? Thermal circuit breakers provide the useful function of modeling the approximate temperature of the wiring that they’re protecting. This prevents what is called “nuisance tripping” on harmless momentary overloads. But it’s possible your replacement circuit breaker is simply no good.
Individual breakers in series with the output terminals other than the common can be useful for two purposes: One is to stop fault currents when those terminals are accidentally connected together, as at block gaps. The other is to allow safe use of lighter wire for feeders, for example, AWG 16 with 10-ampere breakers. However, the common circuit breaker (15 ampere rating in your case) should still be retained if the currents in the individual circuits can sum to more than its rating (40 amperes in the 10-ampere example).
Did a quick test. At full power on the D-U contacts, the new breaker trips at around 5-7 seconds, so it’s working, but with the casing off I can see smoke coming off the wiper, so I’m wondering how much damage that sort of thing does to the roller…
Mitch
Thanks to Bob, BF, and others who have posted here. CTT is a terrific resource. Based on the knowledge I gained, I placed TVS diodes across each of my lock ons and will install them in the modern locomotives I have as I open them for service from time to time.
I just purchased 10amp breakers for use on my zw for my layout on my power feeders. they are bussman 250vac resettable breakers. i have my layout wired with 14gauge wire for the power feeders…here is my question…
I want to wire red indicator bulbs to come on when the breaker trips. How would i do this, if i can…the zw indicator bulb is the type of action i am looking for…i am putting this on my layout and a layout for a xmas display and i want people to see when the breaker trips…
thanks
Put the lamp in parallel with the circuit breaker. When the circuit breaker is closed, the lamp will be looking at a short circuit. When the circuit breaker opens, the lamp will be in series with the load, which will probably be a short circuit (or something close to it if it drew so much current that the breaker just tripped). That will light the lamp. Even when the fault is cleared, the load will probably have such a low resistance that the lamp will remain lit. So, only if you disconnect the load entirely (take the locomotive off the track, for example), will the lamp go out.
I use the tvs all around track and behind zw plus use fast acting breaker
If there is a risk of destroying your old locomotives and/or risk of fire, why not just purchase a new Lionel Transformer? Will this do the trick?
There is no risk of destroying your old locomotives and/or risk of fire(no more today than in 1948, anyway). The ZW is just fine as long as the cord is good.
This stuff added is just to protect with your current trains with the older transformers, but even if I had new style transformer I would still put this stuff on for added protection.
Hi jeff can you tell me how many amps is the tvs, also can you tell me full name Of product .do I need to install one on negative feeder also? and where can I purchase the breaker thank you …
Mazz if you go back and read the post you can get most of your answers on the TVS.
Not sure what Jeff uses but I use Bussmann BP/CB211-10-RP fast acting reseting mini fise breakers as in the picture below. They are 10 amp and protect the wires from the ZW to the track and anything else. They work great for me. You can get them at most any auto store or on line at Amazon or E-bay.
thanks will go RadioShack today…
I recently purchased an Eaton Miniature Breaker 3amp. I saw a video where the engineer stated a 3amp rating was better than a 5amp or a 1amp breaker for running post-war trains. What do you think about that? I see that it seems the protection is really for the Transformer. In my case, I don’t run modern engines. Besides the transformer issue of protection, what is the best protection for the operator against being electrocuted. I am new to all this.
I see you have another post going on installing a circuit breaker in the power line. I guess there is nothing wrong with doing that, but I don’t think it is commonly done.
Many people, myself included, recommend using external circuit breakers on the output side with the larger Lionel transformers like the ZW and KW.
There are several reasons for doing so.
The internal circuit breakers in these transformers are only designed to protect the transformer itself, and may not provide protection of your wiring or trains. (Note: there is only one breaker in most postwar Lionel Transformers, including the ZW and KW).
Also, the internal circuit breakers do not protect every potential circuit.
I like to use Postwar Lionel #91 adjustable electromagnetic circuit breakers on each of the “hot” power terminals on my transformers. That would be the A,B,C and D terminals on a ZW. I adjust them just high enough that whatever train I am running does not trip the breaker.
(It is possibile to tighten the adjusting knob so tightly that the breaker cannot trip. Don’t do it!)
When a short occurs, the breaker will trip instantly. Some people find this annoying. Not I.