Subtask 10.1.4 Operate Electrical System Flashcards
What is the minimum voltage for Batt 1 and Batt 2 during the safety and power-up checklist?
22.5 v
Understand AC power priority.
The source priority order for powering AC bus 1 and AC bus 2 – the order is as follows;
1.Respective IDG (“Onside”)
2.APU Generator (“Inside”)
3.AC GPU (“Outside”)
4.Opposite IDG (“Cross-side)
What are two main components on the DC HOT BAT BUS 1 and 2 that we care about?
Battery 1 and Battery 2, respectively.
What types of circuit breakers does the E175 have? How do I access them?
There are thermal and electronic circuit breakers – some thermal are located in the cockpit. Other thermal are in the electronics bay and must be checked through the MCDU. All electronic are located in the electronics bay and must be checked on the MCDU.
Briefly explain the purpose of the RAT.
The RAT (Ram air turbine) converts airflow to AC power. Whenever AC power sources are not powering the AC buses in flight, the RAT is automatically deployed and after (8) seconds.
What EICAS message would indicate the RAT has NOT deployed during an electrical emergency?
ELEC EMERGENCY, and/or BATT DISCHARCHING [EICAS] message
What AC busses are energized during an electrical emergency before the RAT deploys?
AC STBY BUS
What AC busses are energized during an electrical emergency after the RAT deploys?
AC ESS BUS
What items are on the AC STBY BYS? AC ESS BUS?
AC STBY BUS – Engine 1 Exciter 1A, Engine 2 Exciter 2A
AC ESS BUS – AC Fuel Pump 2A, ACMP 3A, SF-ACE 1 FLAP CH 1, SF-ACE 2 SLAT CH 2
What causes an Electrical Emergency?
Loss of normal sources of AC power (APU/IDG)
Design philosophy –
CA flies
-NAV/COM1
-IRS 1
-CCD1
FA plays in their box
-FMS2
-MCDU2
-GPS 2
What will cause the RAT to deploy automatically?
Whenever AC power sources are not powering AC buses.
What speed is needed to ensure the RAT continues to provide electrical power?
130 knots to provide electrical power
What purpose does an inverter serve?
Converts 28v DC power from batteries to 115v AC power to supply the AC STBY BUS when an AC power source is not available
What purpose does a transformer rectifier unit (TRU) serve?
TRUs are used as a primary source of the DC electrical system, converting AC power to DC power
What is the difference between OFF and DISC on either IDG selector?
OFF= opens the IDG contactor isolating the IDG from the respective AC BUS
DISC= mechanically disconnects the IDG (must be held in position for 1s)
