Electrical System Flashcards
What are two main components on the DC HOT BAT BUS 1 and 2 that we, as pilots, care about?
Engine fire protection system and refueling panel
What type(s) of circuit breakers do(es) the E170 have? How do I access them?
Thermal and Electrical. Electrical CBs are found on the MCDU/FMS
What is the primary purpose of a TRU?
Convert AC to DC
In an electrical emergency, the batteries will provide at least ___ minutes of electrical power.
10 minutes, 2 APU Starts
Briefly explain the purpose of the RAT
Provides emergency AC power in case of IDG/APU failure.
A DC GPU can replace battery ___ in the event it is inoperative for APU starts.
Battery 2, only powers BUS 2 OR APU Start Bus. The DC GPU hookup only powers the APU Start BUS
Can the AC STBY BUS start the engine?
Yes. It is powered from a DC Bus and Inverter which allows for engine start with no AC power.
When Battery 1 is switched on what happens? What about Battery 2 to AUTO?
Battery 1 ON supplies power to the DC BUS 1 and the Hot Battery Bus.
Battery 2 automatically powers EITHER DC BUS 2 OR APU Start Bus
Sources of AC power include…
2 IDGs, APU, GPU, RAT, Inverter
What considerations are there when disconnecting an IDG?
Mechanically disconnects IDG from gear box and switch must be held in 1-3 seconds. A reset by Mx is required when disconnecting IDG
What considerations are there when disconnecting an IDG?
Mechanically disconnects IDG from gear box and switch must be held in 1-3 seconds. A reset by Mx is required when disconnecting IDG
What does the amber light on the IDG panel indicate?
System senses low oil pressure or high oil temperature. EICAS message will display
What does the amber light on the IDG panel indicate?
System senses low oil pressure or high oil temperature. EICAS message will display
What do the AC Bus Ties do? What happens when the switch is turned to 1 OPEN or 2 OPEN?
If one of the AC power sources fails, the AC Buses automatically connected by bus tie contactors (BTCs). One AC power source is sufficient to supply the whole system without significant degradation or additional workload.
1 OPEN: opens the Bus Tie Contactor (BTC) 1, segregating AC BUS 1 from AC BUS 2.
2 OPEN: opens the Bus Tie Contactor (BTC) 2, segregating AC BUS 2 from AC BUS 1.
What happens to protect against an overload on the system if one AC power source fails?
The system will load shed the galleys and right windshield heat.
What is “Electrical Power Priority?”
AC Bus 1 and 2 independently will seek out Onside, Inside, Outside, Cross-Side
After starting the left engine with the APU on, what generator will power AC BUS 2? What powers AC BUS 1?
APU, IDG 1
When the GPU AVAIL light comes on what does that mean?
“AVAIL” is displayed when the AC power meets the specific quality requirements (voltage, amperage, and frequency).
How long does it take the RAT to deploy and begin producing AC Power?k
8 seconds, will automatically deploy and can be manually extended. During the powerup the batteries supply essential loads for 10 minutes
What AC BUS does the RAT connect to?
AC ESS BUS
What items are on the AC ESS BUS?
AC Fuel Pump 2A, ACMP 3A, SF-ACE 1 Flap, and SF-ACE 2 Slat
What EICAS message should go away when the RAT deploys?
Batt Discharge
What speeds are required to get the RAT spinning and to keep it spinning?
150 to get the RAT spinning, 130 to keep the RAT spinning
What kind of batteries do we have in the ERJ 175?
2 Sealed Lead Acid Batteries (SLABs) at 24V in a 28V system
