Use of TVS/diodes with Lionel Postwar transformers

You will need to add in a transient voltage suppressor (TVS for short) rated at 32 volts AC and must be bi-directional and attach either at the back of each transformer output; A to U, B to U, C to U and D to U or at each wire hook-up to the track. At each wire hook-up put one wire from the TVS unit on # 1 and the other wire on # 2. It would seem that you are shorting out the terminal outputs but the TVS will not allow that to happen and will prevent over voltage spikes that can harm newer engines.

Also you might want to use a 7 or 8 amp circuit breaker on the hot side after the TVS unit as the post war transformers can put out some hefty amps before the circuit breaker trips. These post war transformers have a factory 15 amp circuit breaker inside the transformer.

FYI: some voltage spike inhibitors(depending on who makes it) may not fully protect like a transient voltage suppressor will. The TVS costs around $3.50 a piece on line and are well worth the small extra cost. Otherwise you will need a new transformer at over $375.00 and up to $800.00 depending which new transformer you buy.

Lee Fritz

Westy, I am just getting back into using my rebuilt ZW and have installed the "U-Buy" TVS diodes on the terminals. Somewhere in this forum is a post of what the hookup  looks like.  If you need a push from a helper let me know. Cordially, Graham

Yes you can do it like this also. From what I have heard ( I think it was  from Bob Nelson ) the closer it is to the engine's electronics the better. so this would be as far away as you could get and the least effective in protection. I use mine at the LockOns.

Westy, if you need a "visual aide ", send me your e-mail addy and I will return an image of the diode connection if you need it. Cordially, Graham

Here are a few shots to help.  MY ZW powers accessories and the big loads are on the two outside busses.  If you look closely you will see the TVS units from common to hot.  My loops for the trains are powered by Z-1000s and here is a picture of one of them (look close) and also a lock on.  Send me an email and I can send you a few- I have extras.

overbore posted:

From what I have heard ( I think it was  from Bob Nelson ) the closer it is to the engine's electronics the better.

 

TRUE!

I posted about putting TVS diodes in engines here a long time ago, but my name isn't Bob Nelson.

So, a TVS diode installed in an engine is good added protection? How much does it cost?

Walter, yes the best place is inside the engine (per GRJ).  I would put some additional ones on the power wires for added protection in case the one in the engine fails.

Westy,

Here is a diagram of the set up I would use.  I would have a TVS at each track connection, and one at the transformer as backup.