Over-Voltage Warning System; Voltage Regulator/Alternator Control Unit - Cessna T182 Series Service Manual

MODEL 182 & T182 SERIES SERVICE MANUAL
16-50.
OVER-VOLTAGE WARNING SYSTEM.
over-voltage sensor.
If the over-voltage condition
was transient, the normal alternator charging will
16-51. DESCRIPTION.
The over-voltage warning
resume and no further action is necessary. If the
system consists of a sensor switch and a red warning
over-voltage tripoff recurs, then a generating system
light labeled, "HIGH-VOLTAGE", on the instrument
malfunction has occurred such that the electrical
panel.
When an over-voltage tripoff occurs the over-
accessories must be operated from the aircraft bat-
voltage sensor turns off the alternator system and tery only.
Conservation of electrical energy must be
the red warning light comes on.
The ammeter will
practiced until the flight can be terminated. The over-
show a discharge.
Turn off both sections of the Mas-
voltage light filament may be tested at any time by
ter Switch to recycle the over-voltage sensor.
If the
turning off the "Alternator" portion of the master
over-voltage condition was transient, the normal al-
switch and leaving the battery portion on. This test
ternator charging will resume and no further action
does not induce an over-voltage condition on the elec-
is necessary.
If the over-voltage tripout recurs,
trical system.
then a generating system malfunction has occurred
such that the electrical accessories must be operated
If the alternator low voltage light comes on when a
from the aircraft battery only.
Conservation of elec-
COM radio transmitter is keyed the following correc-
trical energy must be practiced until the flight can be
tive action should be followed.
terminated.
The over-voltage red warning light fila-
a. Inspect COM coax connections at the radios and
ment can be tested by turning off the Alternator por-
antennas for security and proper installation.
tion of the Master Switch and leaving the Battery por-
Replace as required.
tion turned on.
This test does not induce an over-
b. Ensure the COM coax shielding is properly
voltage condition on the electrical system.
grounded.
Beginning with 1979 Models the over-voltage sensor
c. Inspect routing of COM coax and reroute as re-
is contained within the alternator control unit. The
quired to provide separation from the alternator
unit also contains a low-voltage sensor.
A red warn- wiring.
ing light labeled "LOW VOLTAGE" is installed on the
d. Inspect alternator control unit connector for loose
instrument panel.
When an over-voltage condition
or improperly installed contacts and replace or
occurs the over-voltage sensor turns off the alterna-
repair as required.
tor and the voltage in the system drops. When system
e. Inspect COM coax cables for damage where se-
voltage drops below 24. 8 volts the low-voltage sensor
cured with ty-wraps. Cables that have been crush-
turns on the low-voltage light indicating a drain on the
ed or deformed should be replaced.
battery and the ammeter will show a discharge.
Turn
If the above inspection does not correct the problem a
off both sections of the master switch to recycle the
new alternator control unit may be installed.
2. Voltage Regulator
3. Screw
4. Housing
8. Wire to Alternator "A+"
9. Wire to Over-voltage Light
Detail A
THRU 1977 MODELS
Figure 16-5. Voltage Regulator/Alternator Control Unit (Sheet 1 of 4)
16-33