Electrical System

Question 1

What sources of electrical power are used for engine cross start operation?

Answer 1

Main battery is used up to 10% NH.

Main battery assisted by opposite DC generator from 10% to 45% NH.

Question 2

How is constant frequency AC power obtained to power the AC busses?

Answer 2

From DC power through 2 inverters.

Question 3

What is the nominal voltage of the DC generators?

Answer 3

30V

Question 4

What is the capacity of each battery?

Answer 4

Main battery - 24V/43Ah

Emergency battery - 24V/17Ah

Question 5

What drives the DC generators?

Answer 5

Driven by the HP spool through the accessory gear box.

Question 6

DC SVCE/UTLY BUS shed amber light on the MAIN ELC PWR panel is illuminated when:

Answer 6

At least one DC ULTY BUS or the DC SVCE BUS is shed.

Question 7

The STBY BUS UNDV amber light is illuminated when:

Answer 7

DC STBY BUS voltage <19.5V

Question 8

After a dual DC GEN loss, the UNDV is triggered when the DC STBY BUS <19.5V.
What happens when the STBY BUS OVRD P/B is depressed?

Answer 8

The DC and AC STBY BUSSES are transferred from the HOT MAIN BAT BUS to the HOT EMER BAT BUS.

Question 9

Inverter 1 normally supplies:

Answer 9

AC BUS 1 and AC STBY BUS

Question 10

At what % NH does the DC generator come on line?

Answer 10

61.5% NH

Question 11

Which bus is shed with a single ACW generator off line?

Answer 11

ACW SVCE BUS

Question 12

What drives the ACW generator?

Answer 12

The reduction gear box.

Question 13

When is an ACW generator available?

Answer 13

NP>66%

ACW is not available in Hotel Mode or when the propeller is feathered.

Question 14

The TRU is used to convert ACW to DC. Which busses does it supply power to?

Answer 14

DC EMER BUS, DC ESS BUS, DC STBY; AC STBY BUSSES.

Question 15

With no external power, no engines running and the battery switch OFF, which items does the GND HDLG BUS power?

Answer 15

The refueling panel
The cargo door control panel
The cabin door
The HYD AUX PUMP P/B