David Lesher wrote:


There are also 3 small {~5A} diodes to provide field excitation. At
startup, the battery will supply the needed field excitation, but
as soon as the alternator is working, they take over the job. (They
are integral to the idiot line scheme in cars, however, so may not
exist in aircraft units.)

Negative. Neither the Prestolite (Ford style) alternators used on
Cessnas, nor the Chrysler alternators used in Pipers have the additonal
"diode trio". Only the aftermarket STCed INTERAV conversion uses
a Motorola alternator with the diode trio.

MikeM
Skylane '1MM