ND 14824 alternator and external voltage regulator

[00Dan]

I've been using a Duralast ND clone alternator on my plane, PN 14824. I chose it as a drop-in replacement when I did my engine swap (the old Motorola I had didn't have a mounting solution). Recently, I started experiencing alternator cutouts, where it would roll back to zero, then come back up, then out again, eventually deciding to stop. I replaced the alternator with a new one yesterday, same PN, and experienced the same problem. I'm now investigating the regulator.

The problem comes in with the fact that I have (on paper) an internally regulated alternator. I hadn't looked too closely at the system that the builder installed previously (I previously thought it was some sort of crowbar OVP setup), and today saw what appears to be an external voltage regulator mounted on the firewall that the field wire goes to. It's a four post regulator with the field input, nothing on the stator pin, and I and A terminals going up into the cabin; the A wire goes through an unmarked box which I assume is either an OVP relay or maybe a noise filter of some sort. I still need to finish tracing the wires behind the panel, but at some point they run to the alternator controls which consist of a switch and a 5 amp breaker.

Have I inadvertently been running piggybacked voltage regulators this whole time? Should I bypass the firewall mounted regulator, and if so how would it be wired? Or should I fire the parts cannon at that regulator (I see a few Duralast part numbers that may work, but I'm not sure which) and go on my way?

 

[00Dan]

I traced the wiring as currently configured today.

The B lead goes from the alternator to one side of the master solenoid. On that same stud, a second wire goes up to a 50A breaker which then feeds the main bus.
The "field" lead from the alternator went to the "F" terminal on the VR. The "I" terminal on the VR goes up to the alternator switch, which then goes across to a 5A breaker that connects to the main bus. The "A" terminal on the VR goes to an old Prestolite overvoltage relay, which then goes to the same 5A breaker the alt switch connects to.

As I understand the wiring for these internally regulated alternators, all I need to do to bypass the external VR and the crowbar would be to jumper the field wire with the wire going to the switch. What I'm not sure of is integrating the crowbar, I'm not finding much on how to wire them with IR alternators.

An idiot check would be appreciated here.

 

[Flyyak]

I am not an electrical guru but I use a nippon denso auto alternator that I modified to use an external regulator (B and C). I hope I can attach an article which was printed in Kitplane. It was not difficult to follow the instructions and I have had no issues. When my original Vans IR nippon denso clone (I think for a Suzuki Samarie) 60 Amp died from a bearing failure, I took it to a local alternator shop I have used over the years for autos and who remanufactured a core using a heavy duty setup. They also made a couple of extra bushing units and I carry one in my tool kit bag in case I break down while away from my hangar. Hope this helps