voltage regulator questions

After doing some more digging, I've come back here to eat my words and offer some additional information that hopefully will help to clear up the "shunt regulator" controversy.  Mike Miller and Rotax Wizard are indeed correct.

I found some articles on a French website that show detailed analyses of the Rotax UL/ULS alternator and regulator, and an explanation of how the regulator works (suggest using your browser's built-in translation feature to read these in English):

Alternator: http://contrails.free.fr/elec_alt_rotax.php

Regulator: http://contrails.free.fr/elec_ducati.php

Shunt or Series?: http://contrails.free.fr/elec_regul_serie_shunt.php

I also found the attached PDF, which helps to explain the regulator's operation.

Finally, it looks like our Mike Miller has been hiding his proverbial light under a bushel!  The same French website as above shows his design for an improved version of the Rotax/Ducati regulator.  It uses the same operating principle, but with better mechanical and thermal design.

Miller Regulator: http://contrails.free.fr/elec_alt_miller.php

Well done, sir!

This is the regulator I am probably going to use. It is not a retrofit to the Ducati since it uses ring terminals, (better than flag). It does not have the overvoltage output but most EFIS panels can set up an alarm on their own.

https://bandc.com/product/pmr1d-regulator-14v-homebuilt/

As promised, the technical response, from CARMO, to my over voltage enquiry:

"............Yes, the CARR5115 is a modern MOSFET voltage regulator with built-in overvoltage protection. Unlike older shunt-type regulators, this MOSFET design offers more precise voltage control, less heat, and greater reliability, especially important in aviation setups like your Rotax 912 ULS.

If the voltage exceeds safe limits, the regulator actively protects both itself and the electrical system.

.................

Kevin van Hout"

😈