Small correction: "The sudden high current overheats the diodes and they fail open" When the battery is disconnected while the alternator is charging the existing field current will generate a high voltage spike that exceeds the reverse voltage breakdown value. Normal diodes are rated for 60-100V reverse voltage. The spike can be lot more; depending how high was the charging current (more>higher). The P/N junction will punch through, the resulting localized current can make it open or short.
Overloading forward (normal direction) current will heat the chip and the carefully placed 'impurities' will migrate and make the diode a little or lot leaky. Unless you fuse the internal connection, the open. Leslie. Phoenix C&C32 1983 -------------------------------------------- On Tue, 7/19/16, Josh Muckley via CnC-List <[email protected]> wrote: Subject: Re: Stus-List Relocating the Yanmar key now alternator.. To: "C&C List" <[email protected]> Cc: "Josh Muckley" <[email protected]> Date: Tuesday, July 19, 2016, 9:31 AM I have heard all of this before and am still electrically confused. I have a few theories but no proof. In the face of my theories is the fact that it is not consistently repeatable. So here goes. Turn the battery off while running and the alternator suddenly goes to full output kinda like shifting to 1st while going 70mph. I get that. The sudden high current overheats the diodes and they fail open. Turn the key off while running and one of two things happens. 1st option is that nothing about the alternator is wired to the ignition and nothing happens. I _______________________________________________ This list is supported by the generous donations of our members. If you like what we do, please help us pay for our costs by donating. All Contributions are greatly appreciated!
