Diamond Aircraft DA 40 NG, Airplane Flight Manual

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DA 40 NG AFM
Airplane
Description
Doc. # 6.01.15-E Rev. 3 01-Jul-2014 Page 7 - 41
Distribution
Electrical power is distributed via the hot battery bus, the battery bus 1, the battery bus 2,
the ECU-bus, the main bus, the essential bus and the avionic bus.
Hot Battery Bus:
The hot battery bus is directly connected to the main-battery installed in the relay junction
box and cannot be disconnected from the main battery. The hot battery bus provides power
to the accessory power plug and ELT which are protected by their own fuses.
Battery Bus 1:
The battery bus 1 is connected to the main-battery via the battery-relay which can be
controlled by the ELECTRIC MASTER key switch. The battery bus 1 provides power to
the battery bus 2 and heavy duty power to the starter.
The battery bus 1 is also connected to the power input line of the external power plug.
Battery Bus 2:
The battery bus 2 is connected to the battery bus 1 via a 100 A fuse and provides power
to the ECU bus via a 80 A fuse. It also provides power to the main bus via the power relay
which can be controlled by the ELECTRIC MASTER key switch and the ESSENTIAL BUS
switch. The ELECTRIC MASTER key switch must be set to ON and the ESSENTIAL BUS
switch must be set to OFF to connect the battery bus to the main bus.
ECU Bus:
The ECU bus is connected to the battery bus 2 via a 80 A fuse and provides power for
the ECU A and ECU B and their fuel pumps. It is also connected to the power output line
of the alternator via a 100 A fuse. It also provides power for charging the ECU backup-
battery. The ENGINE MASTER switch must be set to ON to activate the ECU A and ECU B
to the ECU bus.