Posted for "Gary Casey" <glcasey@adelphia.net>:

<<1) Use a linear regulator in you airplane. Older voltage regulators
modulate the field current in the alternator by periodically connecting
it to the full buss voltage. The average voltage from the alternator is
"regulated" but the ripple voltage is large and must be absorbed by the
battery.>>

While I agree that a "linear" regulator is preferable, I don't agree with
the reason.  A normal regulator pulse-width-modulates the field current and
while the voltage to the field is chopped, the current in the field is
nearly constant because of the high inductance of the field and the
"free-wheeling" diode in the driver.  I think you'll find the characteristic
of the alternator output is essentially identical.  The advantage of the
linear regulator as sold by B&C is that there is less Electromagnetic
Interference (EMI) caused by the regulator.  That difference may or may not
be enough to justify the linear regulator, depending on the susceptibility
of the rest of the system.

Gary Casey
ES #157