Cessna 177 SERIES Service Manual

16-39A.
TROUBLE
SHOOTING
THE
ALTERNATOR
SYSTEM
(BEGINNING
WITH
1978 MODELS)
(CONT.)
b. ENGINE
RUNNING
(Cont.)
TROUBLE
PROBABLE
CAUSE
REMEDY
ALTERNATOR
CIRCUIT
Defective
circuit
breaker.
Replace
circuit
breaker.
BREAKER
OPENS
WHEN
BATTERY
AND
ALTER-
NATOR SWITCHES
ARE
TURNED
ON.
OVER-
VOLTAGE
LIGHT
DOES
NOT COME ON.
ALTERNATOR REGULATOR Shorted
field in alternator. Check
resistance from "F"
CIRCUIT BREAKER OPENS
terminal
of alternator to
WHEN BATTERY AND
alternator case, if resistance
ALTERNATOR SWITCHES is less than 5 ohms repair/
ARE
TURNED ON. OVER-
replace.
VOLTAGE
LIGHT
DOES
NOT COME ON.
CAUTION
This malfunction frequently
causes a shorted regulator
which
will
result in an over-voltage
condition when system
is again
operated.
ALTERNATOR MAKES Shorted diode in alternator. Turn off Battery Switch and
ABNORMAL WHINING
remove
"B" Lead from
NOISE alternator. Check reisitance
from
"B"
terminal
of alter-
nator
to alternator
case.
Re-
verse
leads
and
check
again.
Resistance
reading may
show
continuity in one direction but
should show an infinite reading
in the other direction. If an
infinite reading is not obtained
in at least one direction, repair
or replace alternator.
OVER-VOLTAGE LIGHT
DOES Shorted regulator
Replace regulator
NOT GO OUT WHEN ALTER-
NATOR
AND
BATTERY
SWITCHES ARE TURNED ON.
Defective over-voltage
Replace sensor.
sensor.
AFTER ENGINE START
Regulator
faulty or high
With engine
not running turn
WITH ALL ELECTRICAL
resistance in field
circuit. off all electrical loads
and
EQUIPMENT
TURNED OFF
turn
on battery and alternator
CHARGE
RATE DOES NOT
switches. Measure
bue voltage
TAPER OFF IN 1-3 MINUTES to ground. then measure voltage
from terminal of alternator to
ground. If there is more than
2 volts
difference
check field
circuit wiring shown on alter-
nator system wiring diagram in
Section 20. Clean all contacts.
Replace components until there
is less than 2 volts difference
between bus voltage and field
NOTE
voltage.
Also refer to battery power system trouble shooting chart.
Change 7 16-12A

Cessna 177 SERIES Specifications

General

Manufacturer	Cessna
Engine Type	Piston
Wingspan	35 ft 6 in (10.82 m)
Seating Capacity	4
Number Built	4, 295
Engine	Lycoming O-360
Horsepower	180 hp
Maximum Takeoff Weight	2, 500 lb (1, 134 kg)