KV PREP - OVERHEAD PANEL BUTTONS

DC SERVICE switch

Connects the DC Service Bus to the APU BATTERY DIRECT BUS

BATTERY MASTER switch

Connects APU & Main Battery Direct Bus to their respective BATTERY BUS

AC AVAIL / IN USE button

AVAIL - External power connected and ready for use

IN USE - External AC Power unit is supplying the electrical system

AC POWER IDG 1 & 2 button

Used to DISCONNECT IDG from Engine

FAULT - indicates a fault within the IDG (HOT LOP)

IDG will automatically disconnect when an Overtemperature or Overtorque Condition of a CSD (converts engine gearbox speeds to a constant RPM for AC) Occurs

DISC - Electrical solenoid is energized that causes the drive gear to retract from the engine accessory gear box

AC POWER ALTN AC ESS XFER button

ALTN / Alternate button - ESS BUS is being powered by AC BUS 2

Transfer automatic when AC BUS 1 FAILURE

GEN 1 & 2 & APU switches

FAIL / OFF button between GEN

Automatic transfer of associated IDGs failed

How is power connected from the Engine to DC

Engine - Generator - Bus 1 or 2 - TRU - the associated Bus

TRU

Transformer Rectifier Unit - Converts 115 V AC power into 28 V DC power (TRUs are rated at 120 amps)

AC V / Hertz

115 Volt / 400 hertz

Primary source of power for AC

2 IDGs / 1 APU generator

Primary source of power for DC

2 24V batteries / 4 TRUs

FIRE DETECTION FIREX MONITOR

Press for 2 seconds at least. Tests engine and APU fire detection systems, the cargo bay detection systems, and the fire extinguishing systems

HYDRAULIC R & L HYD SOV button

Electrically operated

Purpose - interrupts the flow of hydraulic fluid from reservoir to the EDP (Engine Driven Pump)

R & L BOOST PUMP

ON - boost pump is operating

INOP - low pump pressure, pump failure, pump not armed

GRAVITY XFLOW

OPEN - Indicates Gravity XFLOW SOV OPEN

FAIL - Gravity XFLOW SOV not in commanded position

XFLOW AUTO OVERRIDE MAN/L/R

MAN - Used to override automatic powered XFLOW

WING A/I CROSS BLEED FROM LEFT

Right wing anti-ice valve is closed and the wing cross-bleed valve is open

BLEED VALVES

ISOL

BLEED SOURCE

APU PUMP (PWR FUEL) FAIL/SOV FAIL

1. Selected first to turn ON
2. APU in BITE (Built-in test equipment) and APU SOV OPEN (indicates fuel shut off valve is open) message appears on EICAS
3. APU RPM and EGT will appear
4. Once the test is completed, START/STOP switch is pressed

APU START AVAIL

6. Pressing the button will cause the ECU to energize the APU starter
7. At 95% RPM, ECU will de-energize
8. At 99% RPM, the green AVAIL will appear (indicating APU is available for electrical loading)
9.

CONT IGN

Hydraulic 1, 3A, 3B, 2