ELECTRICAL SYSTEM

Question 1

GENRATOR OUTPUT?

Answer 1

Generator output is normally 115-120V/400HZ AC, 28V DC

Question 2

To cover the broad spectrum of power requirements, two forms of electricity are usually required:

Answer 2

alternating current (AC) and direct current (DC

Question 3

_______ is a form of electricity that flows in one direction (we originally thought from positive to negative, hence why negative is ground). The components of a DC system are very heavy compared to their relative power outputs.

Answer 3

DC: DC

Question 4

_______ reverses direction. ___ power requires less current because of higher voltage and a ground neutral system. This allows the use of smaller aircraft wiring and therefore, less weight.

Answer 4

AC: AC

AC

Question 5

Auxiliary Power Unit (APU), a small, independent gas turbine engine, provides power through a driveshaft to a gearbox that turns a backup generator. Through this generator, the APU provides electrical power and frees an aircraft from being depend on external power. The APU can also ensure aircraft power when the ____________.

Answer 5

engine-driven generators are not operating or fail

Question 6

Generators are used as the main source for either AC or DC power. A generator transforms _________ energy into _________ energy.

Answer 6

mechanical

electrical

Question 7

Generators frequently use a Constant Speed Drive (CSD) to maintain a constant rotational input speed regardless of engine RPM. This ensures a ______________..

Answer 7

steady voltage output

Question 8

Inverter transforms

Answer 8

DC to AC

Question 9

Transformer Rectifier transforms

Answer 9

AC power to DC (AC/DC Totally Rocks)

Question 10

Battery provides ____ power, but it’s primarily used as a source of emergency power should the generators fail and also for starting the aircraft

Answer 10

DC

Question 11

Essential bus:

Answer 11

routes power to equipment required for flight safety (i.e., primary attitude gyro).

Question 12

Primary bus:

Answer 12

routes power to equipment devoted to the aircraft’s intended mission (i.e., radar).

Question 13

Monitor or secondary bus:

Answer 13

routes power to convenience circuits, e.g., cabin lighting.

Question 14

Starter bus:

Answer 14

routes power to start the aircraft’s engines.

Question 15

Circuit breakers provide a means to manually or automatically_______ power. In an abnormal electrical situation such as an ‘overload’ or a short in the circuit (wires), circuit breakers automatically open (“pop out”), de-energizing the circuit which prevents damage to the component or the electrical system. It can also provide a manual control of electrical power to various components in case of troubleshooting, or replacement of components

Answer 15

interrupt

Question 16

Fuses provide automatic circuit protection should an ________ or an excessive amount of current is flowing through the system or to a component

Answer 16

over-load

Question 17

If you lose the generator and the alternator, how is the AC bus powered?

Answer 17

The Battery, via an inverter (converts DC to AC)

Question 18

In an electrical malfunction, which bus do you lose first?

Answer 18

Utility bus

Question 19

With a total electrical failure, what will AC read? What will DC read?

Answer 19

AC will read 28VAC (or 115VAC), DC will read 0

AC lies, DC dies

Question 20

How many volts is a modern aircraft electrical system?

Answer 20

28 VDC