Supplement Airplane Maintenance Manual
Cessna 172 with TAE 125-02-99 / -114
AMM-20-02
Rev. No:
Rev. Date:
Chapter:
Issue:
Issue Date:
Page:
Content:
20-AMM-24-02
3
06.11.2013
1
16
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25.08.2014
24
ELECTRICAL POWER
24.00
GENERAL
DESCRIPTION AND OPERATION
There are different electrical system variants possible:
•
14 Volt or
•
28 Volt
The 14 V system is equipped with a 90 amp alternator, a 14 V
starter, a 12 V battery and an excitation battery for the alternator.
The 28 V system is equipped with a 60 amp alternator, a 28 V
starter, a 24 V battery and an excitation battery for the alternator.
The alternator and the battery are operated by a separate rocker
switch (BAT and ALT) located on the instrument panel.
The excitation battery of the alternator is operated with the BAT
switch simultaneously.
The alternator warning light (AWL), that is installed in the light
panel or on the instrument panel will illuminate if the alternator
fails to produce current, accompanied by a zero indication on the
AED-125.
The battery switch (BAT) must be ON before any electrical
equipment will operate.
In addition to the main battery and alternator, a backup battery
which only supplies power to FADEC A is part of the electrical
system when installed.
The FADEC backup battery is integrated into the electrical
system without manual control. The pilot can not manually switch
the FADEC backup battery on or off. Under normal operating
conditions when the alternator voltage is greater than the battery
voltage, the alternator charges the battery.
In the event of an alternator failure and a depleted or failed main
Battery, the FADEC backup battery is the only power source and
will automatically supply power to FADEC A. This prevents the
engine from stopping in the unlikely event of interrupted power
supply from both alternator and main battery.
For wiring diagrams of the electrical systems refer to Chapter 91,
Section 91.10 of this supplement.
WARNING:
When operating on FADEC backup battery only, the "Force B"
switch must not be activated. This will shut down the engine.
Содержание Cessna 172
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