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and is ON in
the
up position
and
off in
the
down position.
The right
half
of
the
switch,
labeled
BAT,
controls
all electrical
power
to the
aircraft.
The left half,
labeled
ALT,
controls
the
alternator.
Normally,
both
sides
of
the
master
switch should
be used
simulta-
neously;
however,
the
BAT
side
of
the
switch
could be
turned
ON
separately
to
check
equipment
while
on
the
ground.
The ALT
side
of
the
switch,
when placed
in
the
off position,
removes
the
alternator
from
the
electrical
system.
With
this
switch
in
the
off position,
the
entire
electrical
load is placed
on
the
battery.
Continued
operation
with
the
alternator
switch
off will reduce
battery
power
low enough
to
open
the
battery
contactor,
remove
power
from
the
alternator
field,
and prevent
alternator
restart.
AMMETER.
The ammeter
indicates
the
flow of current,
in amperes,
from
the
al-
ternator to the
battery
or from
the
battery
to the
aircraft
electrical
sys-
tem.
When
the
engine
is operating
and
the
master
switch
is ON,
the
ammeter
indicates
the
charging
rate
applied
to the
battery.
In
the
event
the
alternator
is not functioning
or
the
electrical
load exceeds
the
output
of
the
alternator,
the
ammeter
indicates
the
discharge
rate
of
the
battery.
OVER-VOLTAGE
SENSOR
AND
WARNING
LIGHT.
The aircraft
is equipped
with an automatic
over-voltage
protection
system
consisting
of an over-voltage
sensor
behind
the
instrument
panel
and
a red warning
light,
labeled
HIGH VOLTAGE,
below
the
engine
instrument
cluster.
In
the
event
an over-voltage
condition
occurs,
the
over-voltage
sen-
sor
automatically
removes
alternator
field
current
and shuts
down
the
alternator.
The red warning
light will
then turn
on, indicating
to the
pilot
that the
alternator
is not operating
and
the
aircraft
battery
is supply-
ing all electrical
power.
The over-voltage
sensor
may be reset
by
turning the
master
switch
off and back
on again.
If
the
warning
light does not illuminate,
normal
alternator
charging
has resumed;
howeveg,
if
the
light
does illuminate
again,
a malfunction
has occurred,
and
the
flight
should
be
terminated
as
soon
as practical.
The over-voltage
warning
light
may
be
tested
by
momentarily
turning
off
the
ALT portion
of
the
master
switch
and leaving
the
BAT portion
turned
on.
2-5
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