I have a question. If your running a 3 engine consist and 1 engine picks up a piece of ballast and jams the gears up,then other 2 engines start dragging the jammed engine around layout before u see its being dragged. Now would an tvs circuit protect the proto sound 3 board from becoming toast? This just happened on my layout. And now i have a dead engine .It jammed up while it was in hidden part of layout. thx in advance for any help.
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TVS Diodes protect against extreme over voltage situations. In your case, you had a stalled motor which resulted in a high current situation. This caused heat to build up and fry the board. Circuit breakers protect against over current situations, but a stalled motor may not be enough of an over current trigger to cause a circuit breaker to trip unless you have things finely tuned. You need both TVS Diode and Circuit Breakers/fuses to protect against both types of detrimental conditions. In addition, an observant operator is your best line of defense. It may not hurt to have a sensitive analog or digital AC Amp meter to monitor minute changes.
A TVS wouldn't have helped in your case. A properly sized fuse or circuit breaker might have, but it probably would have to have been within an amp or two of the normal draw.
TVS diodes only protect against voltage spikes you need one of three possible solutions. A fuse circuit breaker or my preference in this case a PTC resettable poly fuse between the motor and the board. This has been discussed several times on the forum. You will find the entry with the values about 3/4 down the page on the link below. On a twin motor loco a 2A trip PTC fuse is about right. j
PTC and TVS - Some Commonly Used Sizes and Part Numbers (from other threads)
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