11.6

Question 1

What is the main advantage of parallel operation of main AC buses over isolated operation?

Answer 1

All engine driven generators are loaded equally and there is no power loss when one generator fails.

Example sentence: When operating in parallel, the main advantage is that all engine driven generators share the load evenly.

Question 2

Which statement is true for a CSD oil circuit?

Answer 2

It is needed for cooling, lubrication, and to provide hydraulic fluid for the motor pump unit.

Additional information: The CSD oil circuit serves multiple purposes within the aircraft system.

Question 3

How are the engine driven generators of a multi engine aircraft usually operated?

Answer 3

In parallel operation.

Question 4

What is the voltage and frequency required to energise the aircraft electrical system?

Answer 4

115v AC / 400hz

Question 5

What frequency is required for modern commercial AC system?

Answer 5

400Hz

Question 6

What is the voltage of AC generation an distribution in modern aircraft?

Answer 6

115 v AC

Question 7

How is the aircraft normally electrically powered in flight?

Answer 7

Engine driven generators.

Question 8

What is the main source of electrical power when the aircraft is on the ground?

Answer 8

External power.

Question 9

Which statement is correct regarding the hot battery bus bar?

Answer 9

It is always directly connected to the battery.

Question 10

What occurrence would cause the emergency generator to be activated?

Answer 10

When all AC main power sources are lost during flight.

Question 11

Why is an integeral gray collar fitted to certain circuit breakers?

Answer 11

To indicate that they must be pulled by maintenance personnel during maintenance work.

Question 12

Why is an integeral orange collar fitted to certain circuit breakers?

Answer 12

To indicate that they must be pulled by flight crew during abnormal circumstances.

Question 13

On a three phase generator what is the angle between the phases?

Answer 13

120.

Question 14

What does overdrive mean in reaction to CSD operation?

Answer 14

The output speed of the CSD is faster than the input speed.

Example sentence: The overdrive condition can cause excessive wear on the components.

Question 15

What does an underdrive mean in relation to CSD operation?

Answer 15

The input speed of the CSD is faster than the output speed.

Example sentence: Underdrive can lead to inefficient operation of the CSD.

Question 16

What is the purpose of the aircrafts transformer rectifier units?

Answer 16

To convert three phase 115v AC/400 hz to 28 volts DC.

Example sentence: The transformer rectifier units are essential for providing the necessary DC power to aircraft systems.

Question 17

For what purpose are the aircrafts batteries generally used?

Answer 17

To supply emergency power, and the APU starter motor.

Example sentence: The aircraft batteries play a crucial role in ensuring continuous power supply during emergencies.

Question 18

The electrolyte used in NICAD battery is?

Answer 18

A strong alkaline solution

Example sentence: The NICAD batteries require regular maintenance to monitor the electrolyte levels.

Question 19

Why must you never attempt to carry out too many APU starts immediately one after the other?

Answer 19

It will overheat the battery and can damage it.

Example sentence: Excessive APU starts can lead to irreversible damage to the battery.

Question 20

What voltage should you never let a nicad battery discharge below?

Answer 20

22v

Example sentence: It is crucial to monitor the battery voltage to prevent it from discharging below the recommended level.

Question 21

What should you do if the electrolyte used in nicad batteries comes into contact with human skin?

Answer 21

Rinse it off immediately using water or an acid solution.

Example sentence: Safety precautions should be taken to prevent any adverse effects of electrolyte exposure.

Question 22

Why are there two short pins in the external power receptacle?

Answer 22

They ensure that external power can only be applied if the plug is located correctly in the power receptacle.

Example sentence: The design of the external power receptacle prevents incorrect connections for safety reasons.