E175 Electrical System Flashcards
General Components
- 2 IDG’s (Integrated drive generators)
- 1 APU (auxiliary power unit)
- 1 AC GPU (ground power unit)
- 1 RAT (ram air turbine)
- 1 Inverter
IDG general info
- Integrated Drive Generator
- Primary source of AC power
- 2 on the E175, one on each engine
- 115 VAC, 400Hz, 40kVA each
IDG (integrated drive generator) logic
- AUTO: system logic controls the contactor
- OFF: opens the contactor
- DISC: mechanically disconnects the CSD (Constant Speed Drive) from the IDG. Flight crew cannot reconnect the IDG (maintenance function only)
What indications mean that the IDG should be disconnected?
Amber light when accompanied by an EICAS oil message indicates IDG disconnect is required
APU general info
- Secondary source of AC power
- 115 VAC, 400Hz, 40kVA
What is required for APU start?
BATT 1 and 2 or BATT 1 and the DC GPU are required for APU start. BATT 2 is isolated from the network during APU start to exclusively power the APU START BUS.
What sends power to/controls the APU’s FADEC?
BATT 1 is used to control the APU’s FADEC
Voltage required to consider APU start
22.0 VDC minimum must be noted during the Safety & Power On Checklist to consider APU start
Minimum voltage to close the contactor
18.0 VDC minimum required to close the battery contactor
Minimum battery 2 temp for start
-20°C
AC GPU (ground power unit) general info
- Secondary AC power source
- Can be turned ON via three different buttons
- One located on the AC GPU panel (powers AC&DC ground service buses and TRU 1)
- One located opposite the FWD lav (powers AC&DC ground service buses and TRU 1) - One located in the cockpit on the overhead panel (Whole aircraft network)
- CAS message (GPU CONNECTED), Master Caution flasher and aural warning will occur should the parking
brake be released and the AC or DC GPU is still connected to the aircraft - AVAIL – GPU is properly connected and power requirements are satisfied
- IN USE – powering AC system
