Electrical Power Distribution - Garmin G1000 System Maintenance Manual

2.3

Electrical Power Distribution

This airplane uses a multi-bus system, as detailed below and in Figure 2-20. 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 2-21 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 (gyro motor), the
Standby Altimeter (vibrator), standby attitude indicator, standby altimeter, standby airspeed indicator 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 / GFC 700 System Maintenance Manual - 300/B300 Series King Air
190-00716-01
Page 2-13
Revision 1