Hi Paul Thank you very much for your input. I did try to isolate the two regulator outputs from each other with high capacity diodes but they failed within a few minutes. Not sure why. I don't like these type of rectifiers that only do half wave rectification. In my opinion it leaves a very dirty supply which can cause all sorts of noise in radios and intercoms, etc.
What I did was install inline fuses in both legs of each PMA outputs (15A) to protect the windings. These also blew at random intervals. I suspected an intermittent short in the supply cable to the panel but it was perfect. After reading up on fuses I found that fuses are severely de-rated at even mildly elevated temperatures. We upgraded to 20A fuses and that seemed to do the trick. The reason the coils were burning out in the first two instances were poor de-burring of the holes in the accessory case where the coil wires exited the accessory case. No fuses could have saved them from shorting to ground there. I have just re-built another Revmaster motor and I was appalled at what the inside of the case looked like. Wherever the case had been machined for clearance there were burrs just left to drop off the edges whenever they felt like it, No de-burring had been done at all. Contamination of the bearings with ally bits was the reason for the rebuild. The back end of the oil pump where the machining had been done to accommodate the gear shaft had "popped" off and got stuck in the inlet of the pump. Luckily it was too big to pass through. This is an old but very low time motor. I hope that the standard of workmanship is better these days Regards Dene Collett Avlec Projects cc Port Elizabeth South Africa Learn the system that revolutionized online marketing for only $1.0 http://www.7figurenetworker.com?a=1879877 > >-----Original Message----- > >From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net] On Behalf Of > >Paul & Karen Smith > >Sent: Tuesday, October 09, 2012 2:48 PM > >To: 'KRnet' > >Subject: RE: KR> Revmaster alternator question > > > >Dene, have a look at this http://www.zefox.net/~bob/mc/vfr/alternator.html
