Looking for TVS recommendation for Motor driver PCB output to "15V" Pitman

@SteveH posted:

I recently acquired a Lionel 6-38095 TMCC N&W 611J.  I've been looking for over a year for one in my price range and this is by far the most expensive locomotive I own.  I would like to add TVS diodes in two places inside the locomotive to do everything I can to protect it from electrical damage.

I plan to install a 1.5KE39CA TVS diode across the track power inputs to the DCDS.  I also plan to install a 1.5KE39CA across the track power inputs inside the tender to protect the Railsounds board.

My question is regarding which diode would be best to connect across the DCDS output connected to the 15.1VDC Pittman motor that would protect the electronic circuitry inside the locomotive against Transient voltage spikes generated by the motor windings that would occur upon sudden current interruptions caused by a derailment or other sudden loss of power.

Which TVS diode would be ideal across the motor driver output?

If I may, the Lionel boards are quite robust, one thing I learned in electronics is “ the more complicated you make the plumbing, the easier it is to stop up the pipes” (Scotty chief engineer USS Enterprise) he was 100% correct. This engine has run time, and is fine? Chances of issues has passed. The boards are very easy to work on, and all the parts readily available. Always remember “just because we can, doesn’t mean we should”

I do have to go with several previous posts.  While what you propose may work, I live by the old saw...

Don't Fix Stuff That Ain't Broke!

There just aren't enough failures of the DCDS drivers for me to spend the time and effort to equip locomotives with this extra component count.

Just put Cruise M in it. You’re not ever going to hurt that motor and the old Odyssey board isn’t really worth preserving. That was Lionel’s best scale J as far as looks and sound. Just needs 4 chuffs.

@gunrunnerjohn posted:

I do have to go with several previous posts.  While what you propose may work, I live by the old saw...

Don't Fix Stuff That Ain't Broke!

...

I'm in Red Green's camp...  "If it ain't broke, fix it until it is!" and "if it ain't broke, you aren't trying".

@gunrunnerjohn posted:

Steve's locomotive would be Odyssey I with the classic TMCC Magnet ring on the flywheel and a hall effect sensor.

If there's a processor chip looking at motor speed, and that processor is directing the H-bridge, might there be stall protection code in the processor?  For years, the other brand of engine has an interesting stall protection feature.  For example, if you manually grab and hold the engine to force a motor stall, the processor will detect this (lack of motion with motor driver at full tilt) and disconnect the FET drivers.  Then it will wait a few seconds (or whatever) and try again.  Lather, rinse, repeat.

My sense is that Odyssey I has no stall protection.  I can hold the motor and it just keeps trying, and the drivers start heating up.

Thank you all for your help and suggestions.

@Norm Charbonneau posted:

Just put Cruise M in it. You’re not ever going to hurt that motor and the old Odyssey board isn’t really worth preserving. That was Lionel’s best scale J as far as looks and sound. Just needs 4 chuffs.

Norm, one day I may upgrade to the Cruise M and other enhancements.  Right now I'm content with some minor low cost mods.