I recently purchased 2 new diesel engines that according to the dealer had delicate circuit boards that could be fried when using an older transformer (a ZW) whose circuit breaker would not trip in time if the engine derailed. The dealer suggested getting an in on-line circuit breaker that would trip sooner to save the engine circuit board. He said try automotive stores (which had no such thing) and then the internet. Anyone know where we would get something like this?
jefny
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Read through this thread. You'll also read that they recommend using TVS diodes to protect your engines.
John F,
I use the 10 Amp in line resettable breakers from Train Electrics LLC, in fact I purchased them from the company they bought out years ago. Train Electrics is on the Net. Further I run Legacy & DCS the DCS TIU has Built in TVS protection. I never have any problems using my old ZW or KW transformers, make sure you put 10 Amp resettable Breakers between your Transformer and every Red line going to your DCS TIU, I even do this with my Z4K's. You only need the Breakers on the Red line that eventually goes to the mid rail on your layout. Setting up in this manner you will never have any problems.
The 10 Amp Resettable breakers work perfectly when set up correctly.
PCRR/Dave
1 - As others have stated, use a Transient Voltage Suppressors (TVS) to protect your new locomotives. This would be in addition to an external breaker. I think it is a crime that the manufacturers do not put them in their engines.
2 - It's no secret that I like Postwar Lionel #91 Adjustable Electromagnetic circuit breakers. They trip instantly. There is one caveat: don't overtighten the adjustment knob. It is possible to make it so tight, that the breaker never trips. I have purchased a couple that came that way. I don't imagine how anybody could do that accidentally.
Since they haven't been made in years, the only way to get them is on the secondary market, EBay, swap meets, or stores that deal in used trains.
I got my breakers and TVS from Mouser electronics - https://www.mouser.com/product...%252bIvcPj0NqyWCs%3D
I use 8 amp breakers and they pop much faster than my post war ZW. I’m running all Legacy engines and I have fired a board on one with a derail before installing the breakers.
Very easg to install. Main power to one lead of the breaker. Then a short feeder from the other breaker lead to a single pole switch for block power control. Then feed from the “on” lead of the switch to your center rail.
Use a 5/8 bit to drill a mounting hole in Masonite for the breaker.
I found this video quite helpful and will be installing the Eaton circuit breaker to my Lionel ZW this week!
https://www.youtube.com/watch?v=aVeCPeeeRNk
Note that the Circuit breaker the author mentions is no longer available and has been replaced with Eaton product number FAZ-C3-1-SP. Also available in 5A and a 10A version, which is the one I will probably get. Or, at least I think I will. I am still learning all about this "electricity thang."
-- Dr Joe
LaramieJoe posted:I found this video quite helpful and will be installing the Eaton circuit breaker to my Lionel ZW this week!
https://www.youtube.com/watch?v=aVeCPeeeRNk
Note that the Circuit breaker the author mentions is no longer available and has been replaced with Eaton product number FAZ-C3-1-SP. Also available in 5A and a 10A version, which is the one I will probably get.
I too use those Eaton circuit breakers - they are available in a wide selection of amperages in 1A increments.
There have been a number of threads on circuit breakers on the forum. Bottom line, you want the breaker to trip before damage to the train gear. I damaged wires and circuit breakers inside of engines and lighted cars that derailed across a switch or a power block - the short circuit current was passed from the front roller to the rear roller. In most cases, the internal 24g wires had the insulation melted and were easily replaced. The other case was more expensive as the connection between rollers was a trace across a $$$ circuit board. Power was a Z4000.
I now run instant trip magnetic circuit breakers at home but these are hard to find and expensive. I would advise a fast trip thermal breaker, perhaps rated for less amperage than the Z4000's 10A. The Eaton breakers referenced above look OK but I didn't see trip times on their data sheet.
You can also check your engine's internal wiring and make sure the rollers do not rely on the circuit board to pass current. I have installed a MOV self reset breaker inside engines that I have opened up for repair.
I would advise a fast trip thermal breaker, perhaps rated for less amperage than the Z4000's 10A.
Does such a thing exist?
You can do protection with fuses. It allows for fuse size change, if you want to up/down the fuse size to accommodate the trains. I found 7.5 amps most useful for trains. Accessory 3 amps or less.
Top center. (8) track block circuits (7.5 amps)
Middle Accessory fuses. Most fuses are 3 amps there are 1 amp fuses on some of the accessories.
Grainger supply Click on the link for the fuse blocks. Glass or ceramic fuses are available at most hardware and automotive parts stores.
A big transformer just might put out enough voltage to cook a board at +20v) Especially if someone hit the whistle (25v)
TVSs is not a fuse. It's a "surge sponge" for high voltage. This will do more to protect things from that boogie man than anything.. but,....
Your transformer is partially protected internally; now you're laying track protection. Use only what each line needs 
E.g.., a breaker or fuse on each post, A B C D ! (Accessories should be fused too)
Fuses over breakers add some adjustability if you can't manage the #91, and that's important if you might swing from a modern trolley with less than an amp needed to a Post War 6 motor ABA E and lighted heavy Madisons cars that might want all ten amps
Napa auto has small self resetting thermal units under 10a, they are used in window and seat cuicuits, but usually have to be ordered.
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