Cessna T188C - Page 328

MODEL
188
&
T188
SERIES
SERVICE
MANUAL
16-33.
TROUBLE
SHOOTING
THE
ALTERNATOR
SYSTEM
(14 VOLT
SYSYEM)
(Cont.)
TROUBLE
PROBABLE
CAUSE
REMEDY
ALTERNATOR
SYSTEM
Faulty
wiring
between
alter-
6.
Check
resistance
from
"F"
WILL
NOT
KEEP
BAT-
nator
and
regulator,
or
terminal
of
alternator
to alter-
TERY
CHARGED.
(Cont).
faulty
alternator.
(Cont).
nator
case.
Normal
indication
on
12-volt
systems
is
6-7 ohms
or
11-12
ohms
on
24-volt
systems.
If
resistance
is
high
or low,
re-
pair
or replace
alternator.
7.
Check
resistance
from case
of
alternator
to
airframe
ground.
Normal
indication
is
very
low
re-
sistance.
If
reading indicates
no,
or poor
continuity,
repair
or
replace
alternator
ground
wiring.
Check
bus voltage
with
engine
run-
ALTERNATOR
OVERCHARGES
Regulator
faulty
or Improp-
ning. Normal
indication
agrees
with
BATTERY
- BATTERY
USES
erly
adjusted,
voltage
vs temperature
chart
in
the
EXCESSIVE
WATER.
Cessna
Alternator
Charging
Systems
Service/Parts
Manual.
Observe
ships
ammeter,
ammeter
should
in-
dicate
near
zero
after
a
few minutes
of
engine
operation.
Replace
regulator.
OVER
VOLTAGE
WARNING
Faulty
regulator.
Reset
over-voltage
relay
by
LIGHT
STAYS
ON.
(24-VOLT).
turning
master
switch
(ALT
side)
off and
on.
Check
regulator
by
replacement.
Replace regulator.
Over-voltage
relay
out
of
Warning
light
comes
on
without
adjustment.
over-voltage.
Adjust
over-volt
relay
assembly.
Faulty
over-voltage
relay.
Repair
or replace.
Substitute
relay.
Faulty
field
wiring.
Test wiring
- look
for field
wire shorted to primary
voltage. Repair.
OVER-VOLTAGE
WARNING
Regulator
faulty
or
improperly
1. With
engine
running
turn
off
LIGHT
ON.
(12 VOLT)
adjusted.
Faulty
sensor
switch.
and
on
battery
portion
of
the
master switch. If the light stays
on
shut
down
engine
then
turn
on
the
"BAT"
and
"ALT"
portions
of
the
master
switch.
Check for
,
voltage
at the
"S" terminal
of the
voltage
regulator.
If
voltage
is
present adjust or replace regula-
tor. If
voltage
is not
present
check master switch and wiring
for
short
or open condition.
If
wiring and
switch
are normal
replace
sensor.
16-24