Cessna T188C - Page 331

MODEL
188
&
T188
SERIES
SERVICE
MANUAL
16-34.
TROUBLE
SHOOTING
THE
ALTERNATOR
SYSTEM
(28
VOLT
SYSYEM)
(Cont.)
b.
ENGINE
RUNNING
(Cont.)
TROUBLE
PROBABLE
CAUSE
REMEDY
ALTERNATOR
SYSTEM
WILL
Alternator
output
voltage
quickly
and
voltage
is normal,
NOT
KEEP
BATTERY
insufficient
(cont).
check
battery
for
malfunction.
CHARGED.
(Cont.)
If ammeter
shows
a low
charge
rate
or
any
discharge
rate,
and
voltage
does
not
rise
when
alternator
switch
is
turned
on
proceed
to
Step
2.'
2.
Stop
engine,
turn
off
all
switches.
Connect
voltmeter
between
"F"
terminal
of
alternator
and
ground.
Do
NOT
start
engine.
Turn
on
battery
switch
and
alternator
switch.
Battery
voltage
should
be
present
at "F"
terminal,
less
1 volt drop
thru
regulator,
if not
refer
to Step 3.
3.
Starting
at
"F"
terminal
of alternator
trace
circuit
to
voltage
regulator,
at
"B"
terminal
of regulator
trace
circuit
to
over-voltage
sensor,
to master
switch,
to
Bus
Bar.
Replace
component
which
does
not have
voltage
present
at
output.
Refer
to
alternator
system
wiring
diagram
in
Section
19.
Alternator
field
winding
1.
If voltage
is
present
turn
off
open.
alternator
and
battery
switches.
Check
resistance
from
"F"
terminal
of alternator
to alter-
nator
case,
turning
alternator
shaft
during
measurement.
Normal
indication
is
12-20
ohms.
If
resistance
is high
or low,
repair
or
replace
alternator.
If
ok
refer
to
Step
2.
2.
Check
resistance
from
case
of
alternator
to
airframe
ground.
Normal
indication
is
very
low
resistance.
If reading
indicates
no, or
poor continuity,
repair
or
replace
alternator
grond
wiring.
16-27