Electrical Power Distribution - Garmin G1000 Nxi System Maintenance Manual

Electrical Power Distribution

This airplane uses a multi-bus system, as detailed below and in Figure 2-25. This Figure shows
the system post installation of this STC. Although this STC made several bussing changes to
the distribution system, the core electrical generation and distribution system remains
unchanged from the basic airplane design. Figure 2-26 shows the power sources for all
equipment used by this STC. Each bus used or modified by this installation is described below.
Left and Right Generator Buses: The left and right generator buses receive power from their
respective left and right generators. The left and right generator buses also support Center
Buses and Left Gen and Right Gen Avionics Buses, respectively.
Triple Fed Bus: The Triple Fed bus is powered by left and right generator buses and the battery
bus.
Avionics Buses: The Left Gen Avionics bus is powered from the Left Generator Bus via the
Avionics No. 1 relay. The Right Gen Avionics Bus is powered from the Right Generator Bus via
the Avionics No. 2 relay. The Triple Fed Avionics Bus is powered from the Triple Fed bus via
the Avionics No. 3 relay. All avionics relays are controlled using the Avionics Master Switch.
Left and Right Engine Instrument Buses: On serial numbers FL-120, FL-122 through FL-380,
FL-382, FM-009 through FM-11, the electrical system includes the L ENG INSTR and R ENG
INSTR buses. On all other serial numbers, these two buses are not installed and engine
instruments are powered directly from the Triple Fed Buses.
Emergency Standby Battery: The Standby Emergency Battery (STBY BATT) system in the
King Air 300/B300 is designed to provide uninterrupted DC power to the Standby Attitude
indicator (including gyro motor and internal instrument lighting), the Standby Altimeter (including
vibrator and internal instrument lighting), standby airspeed indicator internal instrument lighting
and internal instrument lighting for the magnetic compass from the L-3 PS-835(C or D Model)
Emergency Standby Battery. This standby battery power is independent from the normal
electrical system and provides redundant power for the standby instruments in the event that all
other electrical power is lost.
G1000 NXi System Maintenance Manual
King Air 300 Series
190-00716-N1
Page 24
Revision 1