@Johnny B posted:Vernon, thanks for the detailed info. I had come across the tvs protection in my research and was planning to implement that in addition to the circuit breaker, now I have a much better understanding of what and why. Seems my z1000 and it's brick is probably sufficient then since it does have breaker protection as far as the amp protection goes? I just need to do the tvs diodes to protect my switch machines from transient voltage (my real problem causing failure), if I'm understanding correctly. Or should I really consider putting another faster breaker externally from my brick?
Correct, while Faster breaker can be better at protecting- key point- "what it can protect"- it was never ever going to protect against the failure mode you are experiencing of the DZ2500.
Electronics typically fail because of voltage. Yes, sure, there are all kinds of failure modes and yes, overcurrent, shorts, jammed and stalled motor are some examples- but a vast majority are either incorrect polarity (I put AC up a DC circuit in this category), or voltage that exceeds a rated component.
I'll be the first to say I advocate breakers. I pound this point all the time- there are lots of folks out there- especially new folks, and being I'm in the repair side of the business- I'm seeing these people because they burned something up and are coming to me to fix it.
But I also stress- a breaker- no matter how fast, no matter how sensitive, will NOT protect against a whole swath of electronics failure. Examples- lionchief drawbar wiring short- connecting the speaker to AC frame common blows the board- there is no "breaker" on the planet that would prevent this. These DZ2500s failing- again no breaker on the planet would detect the current change as the microcontroller chip fails. Unless you had said I have one where the wires melted- a breaker and how long it took had nothing to do with preventing the failure.
Conversely, I cite again the topic https://ogrforum.com/topic/158674373723181699 and this picture of what happens when a modern passenger derails and lack of a breaker and high current burns these to a crisp.
Back to the question:
Is the Z1000 thermal breaker fast enough?
I generally say yes for 2 reasons, the brick power is limited and generally, it kicks in fast enough that extreme damage like the above burned up passenger car situation is not catastrophic.
Did you have similar situations where you actually burned up or melted wiring and or caused damage by extended high current before the breaker tripped? I think a safe assumption is no, you simply had derailments and noted in damage assessments later- the DZ25000 failed.
Length of how long the breaker took to trip did not change the voltage spike in any way, nor would it have prevented it. How long is the danger of cooking wires and traces.
You certainly can add a faster acting breaker in series to any transformer or power source.
As far as protecting electronics- again we believe you have a situation where you knew you derailed, and in doing so spike were generated. This is where the TVS protection kicks in. No breaker can prevent a spike- only a TVS can short the spike to prevent it from then stressing and ultimately failing the electronics.
