Eclipse 500 System Manual page 254

Section 10. Electrical
10.6.2 Engine Start
FIRST ENGINE START
Starting the first engine is accomplished using start battery power or if external power
is available, external power in parallel with the start battery. Engine start is
automatically controlled by the ACS and FADEC. When the start sequence is
initiated, the ACS separates the electrical system into a forward/aft configuration by
opening both left and right forward circuit breaker contactors and closing the right
battery bus contactor and bus tie contactor. In this configuration, the systems battery
powers the avionics components on the forward buses to protect them from voltage
drop due to high starter current. Power from the start battery and external power is
routed through the GCU to drive the starter/generator as a motor. The resulting
mechanical torque is applied through the engine's accessory gearbox to start the
engine.
After the first engine is started and generator power is available, the electrical system
reconfigures to a left/right configuration. Both left and right forward circuit
breaker/contactors close, the right battery bus contactor opens, disconnecting the
systems battery from the right forward bus and the bus tie contactor remains closed
to power both aft buses through the operating generator. If external power is being
used, the external power contactor also opens to prevent reverse current flow.
ONE ENGINE RUNNING
With one engine running and the generator delivering electrical power, the second
engine may be started using start battery power in parallel with the operating
generator. The left and right forward circuit breaker/contactors open, disconnecting
the forward buses from the aft buses during engine start as they were during the first
engine start.
If desired, the second engine can be started with external power paralleled with the
start battery. To do this, the pilot turns off the GEN switch for the operating engine to
allow the external power contactor to close.
234
Copyright © — Eclipse Aviation Corporation
Eclipse 5OO Systems Manual
Version 2.0 April 2007