Good catch by Dan Ballin a fellow Legacy builder.
In talking wth B&C about voltage regulators is seems that in a 24V dual alt system where you use the SD-20 to provide backup alternator and charging for a second battery, that you should use the LS-1A regulator with it *instead* of the LR3C.
Note this only has to do with 24V systems. If you have a 14V one, then the LR3C will work just fine.
This is because the SD-20 is used in either a 14v or a 24v system and the field winding is only a 14V winding. If you use an LR3C with this alternator, it will provide 24 volts to the field and will burn it out. If you use the LS1A, it's regulated on the field output to only provide 14V (scaled to the charging requirements) and so it won't burn out the windings.
This also has direct applicability if you got the power grid fast build option that Lancair provides. I did and got 2 LR3C's. Now I'm trying to exchange one for an LS1A.
Thanks Dan for catching this and saving me some money down the road!
All others plan accordingly.
I'll also get with VP and have them revise and note their regulator drawings.