Beechcraft 20138 - The Model 20138 System

3-5
THE
MODEL
20138
SYSTEM
Figure
3-7
shows a schematic
of
the complete voltage
regulator.
Note
the
following
features.
Extreme
versatility
is
provided by the pin
connector
arrangement.
By
making
suitable external
connections,
the
Model
20138
can:
a) Function
as a
voltage
regulator with overvoltage
protection
circuitry,
b)
Function
as a voltage
regulator
only,
c)
Function
as an overvoltage warning
device only.
In
addition to
the
combinations
listed
above,
pin connections are
available
which
provide
+28.5
volts
normally closed,
(pins H & E) and zero
voltage
normally
open
contacts
for
the
operation
of
an external overvoltage
warning light (pins F & D),
For
normal operation
as
a voltage regulator
with overvoltage
protection:
Connect
pins
A, H,
J,
and
F
together and to the
+28.5 volt
buss.
Connect
Pin
G
to
pin
I.
Connect
pin
D
to the
overvoltage
warning light if
used.
Connect
the
other
side of
the
light to ground.
Connect
pi.n B to the alternator field/fields via
a
suitable
fuse
arrangement
as
shown
in Figure
2-2, Section
2.
3-17