Re: Overvoltage Protector

Posted by Eric Swartz - WA6HHQ on Aug 20, 2010; 11:28pm
URL: http://elecraft.85.s1.nabble.com/Overvoltage-Protector-tp5445892p5446442.html

I'd like to clarify this a bit.

While the K3 does have some protection against over voltage on its supply, we do not garantee it will survive an overvoltage event in all cases.

73,
Eric

www.elecraft.com
_..._



On Aug 20, 2010, at 1:00 PM, Scott Ellington <[hidden email]> wrote:

> Some power supplies, like the Samlex SEC 1235, have no built-in overvoltage protection.  All regulated power supplies are capable of producing much more than their normal output voltage if any one of a number of things fails.  Linear supplies are particularly susceptible, since the pass transistor can short.  
>
> While Elecraft assures me that the K3 can survive an overvoltage with minimal damage, I prefer to be on the safe side.   So I designed a crowbar circuit, which can be used with any 12 V power supply up to 30A.  If the voltage exceeds the trip point (14-16 V), it will short the power supply output and, if necessary, blow a fuse.
>
> http://www.ssec.wisc.edu/~scotte/hr/OVP.pdf
>
> I haven't built this one yet, but a very similar one I built in 1984 worked fine.
>
> 73,
>
> Scott  K9MA
>
> Scott Ellington
> Madison, Wisconsin
> USA
>
>
>
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