Thanks to the responses and advice from y’all on Listserve I have successfully connected a Balmar external regulator to a Delco alternator.
Found several good explanations of the internal wiring of the Delco on the net.
Per your advise; discussed what I intended to do with Balmar tech service and the guy that rebuilt my alternator for me and they said no problem.
The only tricky part of getting into the Delco is holding the brushes back when you reassemble it. For this you stick a wire through holes in the brush holders to hold the brushes back until the two halves are slid together, then you pull the wire out through a hole in the case. When the alternator is open it is surprisingly simple inside and easy to work on.
For those who might be interested, the modification is to ground one of the field brushes to the case, remove the diode trio, and connect a wire to the vacant diode trio terminal on the internal regulator, which is left in place but is now disabled, and lead this wire out through any hole in the case. This is the field connection which connects to the blue field wire from the Balmar regulator.
The Balmar instructions and wiring diagrams are VERY well done and thorough.
I have bench tested the alternator with the Balmar regulator connected and it works just fine.
If anyone is planning to do this, e-mail or call for a more detailed information.
I believe that one of the Sages on Listserve advised, “Don’t put anything on your boat you can’t fix yourself.”
BTW …keeping the diode trio…it can be put back into the alternator if the Balmar croaks…this can be done, on the boat, with simple tools should the need arise.
If you are near the Boston north shore I highly recommend Hub Automotive Rebuilders, 978-356-2996, for alternators and starters, in Ipswitch MA, fast competent reasonably priced work.
Earle and Nancy Beasley
Mariposa 30U
Rowley, MA 01969
Cell 978-857-7866
ebeas1@verizon.net