On Tue, Mar 1, 2011 at 2:13 PM, Ben Okopnik <[email protected]> wrote: > On Tue, Mar 01, 2011 at 02:03:12PM -0800, Jim Richardson wrote: >> Wouldn't even need that (and that would bring in other unrelated >> issues) simply measure the voltage at the shore plug, and main >> breaker. Seeing more than a few hundredths of a volt difference would >> be a good indicator of a problem. > > You won't see any voltage drop, though, until the problem is full-blown > - i.e., melting cable, etc. Even if the wire diameter is cut down by > 3/4, you still won't see any drop - but the "skin effect" at 100MHz > would show a huge difference.
it's true that if the problem is in a very local area, such as the connector. Which is admittedly, the most common failure mode, the increase in resistance will be small. But it is still measurable, even with low current. Although I wonder if an even cheaper approach would be a thermo sensitive dye that changes color above a certain value, say, 50% of the melting point of the cable sheath. Mix it in with the yellow rubber cover material, and if it changes color to say, red, you'll get an immediate visual indicator that requires no tools, and will immediately prompt folks to wonder if something is wrong. You might be able to use a TDR style check, but you'd have to do it from both ends, and compare readings, lest every time the cable gets bumped or moved the system would see a change, and alarm. I don't think that would be a very inexpensive system. I kinda like the thermo sensitive dye approach, I wonder if it's actually practical? Of course, it's a one time fail test, but speaking for myself, I don't trust a cable or connector once it has failed. Not for something like this. > >> Pass the data along the powercable, >> and read it onboard. That does sound useful tbh. Especially if the >> sensor and sending unit could be incorporated in the shore power cable >> end. > > I was actually thinking of a little box, not any bigger than an AC > splitter, with a big red LED on it. That way, even when the cable dies > (which is presumably the only time the gadget would be useful), you'd > be able to shift the unit to the new one. > > > Ben > -- > OKOPNIK CONSULTING > Custom Computing Solutions For Your Business > Expert-led Training | Dynamic, vital websites | Custom programming > 443-250-7895 http://okopnik.com http://twitter.com/okopnik > _______________________________________________ > Liveaboard mailing list > [email protected] > To adjust your membership settings over the web > http://liveaboardonline.com/mailman/listinfo/liveaboard > To subscribe send an email to [email protected] > > To unsubscribe send an email to [email protected] > The archives are at http://www.liveaboardonline.com/pipermail/liveaboard/ > > To search the archives > http://www.mail-archive.com/[email protected] > > The Mailman Users Guide can be found here > http://www.gnu.org/software/mailman/mailman-member/index.html > -- http://neon-buddha.net _______________________________________________ Liveaboard mailing list [email protected] To adjust your membership settings over the web http://liveaboardonline.com/mailman/listinfo/liveaboard To subscribe send an email to [email protected] To unsubscribe send an email to [email protected] The archives are at http://www.liveaboardonline.com/pipermail/liveaboard/ To search the archives http://www.mail-archive.com/[email protected] The Mailman Users Guide can be found here http://www.gnu.org/software/mailman/mailman-member/index.html
