Simple Overvoltage protection

[David Gregory]

I have a 13.8v, 30 amp power supply that is over current protected, but not over voltage protected.

Am I correct in thinking that a simple zener diode across the outputs, and an in-line fuse is all I'll need to have a crude, but effective over-volatge protection circuit?

If I use a zener of 14.4v or there abouts, if voltage exceeds this level, the zener will breakdown and short out the PSU's output, and blow the fuse.

My question is, for a 30 amp supply, what zener will I need to survive the time it takes to blow the fuse, considering it will be drawing 30 amps approx.

I hope I'm making sense

Thanks
David

 

[BobK]

Look up "crowbar circuit"

Bob

 

[Colin Mitchell]

Why would the power supply go over voltage????
What about putting a "stopper" on the control knob ????

 

[David Gregory]

Failed Voltage regulator? Failed, or dirty potentiometer? (it has variable output). I'm assuming it must be plausible to go over voltage, or why else would a great many PSU's have over voltage protection?

Thanks BobK.... A crowbar circuit looks simple enough. I was just looking for something as simple as possible to keep from overly modifying the PSU.