AIRCRAFT
Electrical Power
DA 42 NG AMM
Page 4
15 Mar 2018
24-00-00
Doc # 7.02.15
Rev. 4
2. Electrical System Description and Operation
Figures 1 and 2 show the electrical system simplified schematic diagrams.
A. Power Supplies
(1) Main Battery
The main battery is located in the front baggage compartment and is mounted on the forward
RH side of the cockpit front bulkhead. It is a 24 V, 13.6 Ah sealed battery. The battery is
connected to the main airplane ground, the battery relay and the battery HOT BUS.
(2) Alternators
Each engine has an alternator located at the left rear of the engine. A flat multi-vee belt with
automatic tensioner turns the alternator. The alternator has an external regulator which is
located in the engine nacelle. The output from the alternators connects to the LH and RH
MAIN BUS, through terminal blocks, relays and fuses. In the event of a main battery failure the
alternators can be excited directly from the related ECU backup batteries which are located
below the passengers seat.
Optionally, the RH ECU backup batteries may be installed in the lower tail fin (if OÄM 42-247
%
is installed).
%
(3) External Power Connector
The external power connector is located below the forward baggage compartment. The external
power connector connects to the external power relay in the relay junction box in the forward
baggage compartment.
)
The control pin connects to the relay coil through a diode to prevent reverse connection.
)
The + pin connects to the relay main input connection.
)
The – pin connects to ground.
CAUTION:
WHEN OPERATING THE AIRPLANE ELECTRICAL SYSTEM WITH
ENGINE MASTER ON (LH OR RH) AND THE ENGINE IS NOT RUNNING
(e.g. EVENT LOG READOUT) ALWAYS CONNECT AN EXTERNAL
POWER SUPPLY WITH A PRESET VOLTAGE OF 29 V TO THE
AIRPLANE. OTHERWISE THE ALTERNATORS MAY BE DAMAGED.
ADDITIONALLY, IF MÄM 42-551 IS INSTALLED, SWITCH OFF BOTH
(LH AND RH) ALTERNATOR SWITCHES.
Summary of Contents for DA 42 NG
Page 933: ...AIRCRAFT DA 42 NG AMM Fuel Doc 7 02 15 Rev 4 28 TITLE Page 1 15 Mar 2018 CHAPTER 28 FUEL ...
Page 1459: ...AIRCRAFT DA 42 NG AMM Lights Doc 7 02 15 Rev 4 33 TITLE Page 1 15 Mar 2018 CHAPTER 33 LIGHTS ...
Page 1711: ...AIRCRAFT DA 42 NG AMM Doors Doc 7 02 15 Rev 4 52 TITLE Page 1 15 Mar 2018 CHAPTER 52 DOORS ...
Page 1853: ...AIRCRAFT DA 42 NG AMM Wings Doc 7 02 15 Rev 4 57 TITLE Page 1 15 Mar 2018 CHAPTER 57 WINGS ...
Page 2071: ...AIRCRAFT DA 42 NG AMM Engine Doc 7 02 15 Rev 4 72 TITLE Page 1 15 Mar 2018 CHAPTER 72 ENGINE ...
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