Finn Lassen wrote:

I think the +100 volts statement relates to no battery load.  Have you /anyone actually seen that happen?  I guess if the electrical system was designed so that a contactor could disconnect the battery from the load circuits and the load circuits (avionics) still be connected to the alternator you would have a situation where you could wave your avionics goodbye.
Perhaps.  But that wouldn't be very clever.  Anyone who designed his system to protect his avionics from a Battery over voltage and ignored the Alternator deserves whatever happens.
Let's say on top of that that one (or all) of the three retifiers shorted out too, you'd have 100 volts A/C into your avionics. Not a pretty picture. (I've seen Zener diodes short out regularily due to overload/voltage; rectifier diodes usually fail open - but not always).   We're stretching a bit here aren't we?  Back to the 100 V that we've already agreed can't happen, shorted diodes causing AC (which I'm not at all sure can happen), all three rectifiers (that's all SIX diodes shorting at the same time (none of them failing open which is more common), zener failing, etc.  If a diode fails every 1000 hrs, the whole bank failing would happen every 1000^6 hours.  That's a one with TWENTY ONE zeros behind it.

I think I can live with that ... Jim S.

Finn

Jim Sower wrote:

<... the alternator is capable of producing over 100 volts ...>
I don't think so ...
...
Bottom line, with the regulator failed (or bypassed) to send full B+ voltage to the field, the charging voltage never exceed 18V in my experience.

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