Beechcraft 20138 - Block Diagram

OVERVOLTAGE
WARNING
LAMP
FRDM
+
28V
BUSS
SERIES
SWITCHING
CIRCUIT
->
Q6
-
Q7
TO FIELD
T ION
A
GR3UN
'GROUND
FIG.
3-4
BLOCK
DIAGRAM
-
REGULATOR,
WITH
OVERVOLTAGEPROTECTION
Qgggggio_n_:
The
relay
Kl is
normally
de-energized,
thus
completing
the
circuit from
the
28 volt buss
to the
voltage
regulator circuit.
In the
event of
the buss
voltage
rising
to the
overvoltage
tripout
level,
the
over-
voltage
protection circuit
will
energize relay
Kl. This
action
disconnects
the
28 volt
buss
from the
regulator
circuit,and
therefore,from the
field
winding. Circuitry
within the
overvoltage
protection unit automatically
locks in
relay
Kl. The circuit
can
be reset
by
interrupting the
supply
to the regulator.
The overvoltage
tripout
level is set
at the factory
to
32.0
±1,0
volts
D.C.
but can be readjusted
by
the user
within the range
of 30.5
to
33.5 volts
D.C.
Do
not
make
any
adjustments to the
overvoltage
protection
circuit
without
first reading
the
CAUTION
notice
in Section
4.
3-7