Diamond Aircraft DV 20 E 2022, Airplane Maintenance Manual

Page: 256 / 903

AIRCRAFT
Electrical Power
DV 20 E AMM
Page 2
15 Mar 2022
24-00-00
Doc # 4.02.25
Rev. 2
(3) External Alternator (optional)
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The external alternator is in the scope of supply of the BRP Rotax 912iS engine. The external
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alternator is controlled by an integrated regulator. Refer to Section 24-30 for more information
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of DC Generation.
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Note: When doing prolonged maintenance on the airplane with external power
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connected to the electrical system, pull the ALT.CONTROL and ALT circuit
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breakers to prevent damage to the external alternator.
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B. Power Supply Control
(1) Battery Relay
The battery relay is located on the front left hand side of the firewall, next to the main battery.
The output connects directly to the starter relay and the shunt of the ammeter. The coil + of the
relay is tied to the b. The ELECTRIC MASTER switch provides the coil ground when set
to the ON position.
(2) Bus Structure
All buses are flat metal strips connecting rows of circuit-breakers. The circuit-breakers are
located on the instrument panel on the right side.
(3) Main Bus
The main bus provides power for the consumers. Each consumer has a circuit-breaker to
protect the circuit. The main bus also connects to the avionic bus via the avionic master relay.
A circuit-breaker protects the supply to the relay.
(4) Avionics Master Relay
The avionics master relay connects the main bus to the avionics bus. The AVIONIC MASTER
switch controls the relay.
(5) AVIONIC MASTER Switch
With the AVIONIC MASTER switch set to OFF:
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The avionic master relay is energized to disconnect the avionics bus from the main bus.
With the AVIONIC MASTER switch set to ON:
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The avionic master relay is de-energized to connect the avionics bus to the main bus.