Lesson 2: Electrical system

• Engels
• MBO
• Studiejaar 2

Electrical system

Lesson goals

• You can explain what the difference between AC and DC power is. ​
• You can explain the function of the Electrical system in a plane. ​
•  You can name the components of the Electrical system.
• You will learn about the present continuous and conjunctions.
• Rehearse present simple

Exercise 1a - Answers

Bonus question:

A pneumatic system is a system….

• That extracts air from the aircraft engines or APU and distributes it to a few other systems in an aircraft.

Exercise 1b - Answers

1. Heat exchanger
2. Ducts
3. Regulator
4. Control valve
5. Chemical separator/desiccant
6. Filter
7. Relief valve
8.  (Air) compressors
9. Restrictor
10. Chemical drier
11. Check valve

Exercise 2: Answers

1. What is bleed air?

Compressed, highly pressurized air that is very hot. It is used to power certain systems that require energy from pressurized air.

 

2. Is the temperature of the bleed air stable?

No, it varies a lot depending on where it’s extracted from. It varies from 250 degrees Celsius.

 

3. Name three systems that bleed air provides with power.

Engine one and two start systems, air-conditioning and cabin pressurization, engine one and two anti-ice systems, wing anti-ice systems, water tank pressurization system, hydraulic system A and B reservoir pressurization system, air temperature probe aspiration system and nitrogen gas generation.

Exercise 2: Answers

 

4. What is the function of the pneumatic manifold system?

It collects all the air from the three systems that provide pneumatic power.

 

5. What is the function of the bleed air isolation valve?

It divides the pneumatic manifold in a left and a right side, this provides system redundancy.

Exercise 2: Answers

6. What is the function of the duct pressure transmitters?

It provides indications to the duct pressure pointers in the forward overhead panel.

 

7. From which part of the engine is bleed air extracted?

The compressor section, the 5th and 9th stage.

 

8. What is the function of the fifth stage check valve?

It prevents bleed air from the 9th stage to get into the 5th stage bleed airport.

Exercise 2: Answers

9. What is the function of the PRSOV?

It regulates pressure to 42 psi; it gives bleed air temperature limitation to 235 degrees Celsius and bleed air shutoff.

 

Exercise 3

1. C
   
2. I
   
3. A
   
4. L
   
5. F
   
6. B
   
7. J
   
8. D
   
9. H
   
10. E
    
11. K
    
12. G
    

Present simple - Usage and signal words

Exposure to input 2: 

Students need to listen to the lecture about the present simple

Use of strategies:

Present simple - Form

Which sentence is in the present simple?

1. I am learning how to make bookings.
2. I often learn things quickly.

Processing form 2: 

Check for understanding with a quick Kahoot style quiz. 

Bloom's taxonomy level 3: Applying

Present Simple
Choose the correct form:
She ... at the Sip Café.

1. work
2. works
3. worked

Present Simple
Choose the correct form:
... Rick walk to school?

1. Do
2. Does
3. Don't

Present Simple
Choose the correct form:
Jenny and Maria ... like fish.

1. don't
2. does
3. do

The shit-rule is meant for?

1. Present Simple
2. Present Continuous

1. Present Simple
2. Present Continuous

When is the present simple used?

1. Facts, general truths, Timetable events, permanent states and habits
2. What happens now, demonstrating something and prediction
3. Things that happened in the past and currently
4. Facts about the future events, timetable events and habits

00:56

What is the purpose of the Alternator?

1. To generate power for the entire aircraft system and the battery
2. To generate power for the battery of the aircraft and some systems.

01:28

Why are circuit breakers used in modern airplanes?

1. Because circuit breakers are easy to use and fuses are difficult to repair.
2. Because a circuit breaker is reusable, but a fuse cannot be used again once it is blown.

Exercise 1

Can you name the main components of the electrical system in an airplane? ​

​

Go to exercise 1 and name the electrical components in the aircraft. ​

​

You have five minutes to do so. 

Exercise 1a- Answers

1. Alternator

2. Battery

3. Switches

4. Circuit breakers/ fuses

5. Relays

6. Voltage regulators

7. Ammeter/ Loadmeter

8. Electrical wiring

Exercise 1b- Answers

Remote = afgelegen of geringe, op afstand

Distribution = verdeling​, distributie

External = extern of aan de buitenkant ​

Receptacles = opvangbakken, opvangers of reservoirs​

Forward = naar voren of voorste​

Cargo bay = inham of (berg) ruim 

Aft = achteren of achter(kant)

Equipment = gereedschap of uitrusting 

Exercise 2 (a)

We are going to listen to an explanation of how the pneumatic system works: ​

• Watch the following video and complete exercise 2
• Pay attention: Answer the questions AND fill in the diagram 
• Watch the video called ‘Electrical system’

Exercise 2- Questions

1. What is the purpose of the battery contactor or relay?  
2. What is the purpose of the ground service receptacle plug?
3. On which component can you read how much electrical current is flowing to the rest of the components of the aircraft?
4. What does ‘bus’ mean?
5. How do you keep your motor running?
6. What is the function of the alternator?
7. What is the difference between amps and volt?  

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Exercise 2

Before you start a listening exercise, always remember to:​

• Read the questions first​
  
•  Think about what you already know about the subject​
  
• Remember the keywords that are relevant to the topic ​
  

​

​

Go to exercise 2 and answer the questions while watching the video. 

Exercise 2- Questions

1. What is the purpose of the battery contactor or relay?  
2. What is the purpose of the ground service receptacle plug?
3. On which component can you read how much electrical current is flowing to the rest of the components of the aircraft?
4. What does ‘bus’ mean?
5. How do you keep your motor running?
6. What is the function of the alternator?
7. What is the difference between amps and volt?  

Exercise 2- Answers

1. So you can control a large flow of electricity with a small switch. 
2. You can plug a charger into it, and it helps to recharge the battery. 
3. The Ammeter 
4. It’s a place where a lot of wires meet in the middle and where they split off into a lot of tiny wires. 
5. You need magnetos to supply sparks to your engine. 
6. It can recharge the battery, and it also provides electrical current to the electrical system when its engine is running.
7. Amps are flow and volts are the pressure

Exercise 2 (b)

Exercise 2- Answers

Exercise 2- Answers

1. Alternator control unit
   
2. Low-voltage warning light
   
3. Alternator
   
4. Clock
   
5. Alternator field circuit breaker
   
6. Ammeter
   
7. Oil pressure switch
   
8. Flight hour recorder
   
9. Starter contactor
   
10. To wing flap circuit breaker
    
11. Battery contactor
    
12. Magnetos
    
13. Ground service plug receptacle

Grammar - Present continuous

Present continuous vs present simple

Grammar - Present continuous

1. Present Simple
2. Present Continuous

Lees onderstaande zin. Staat deze in de present continuous of in de past continuous?

She is having a great time tonight.

1. Present continuous
2. Present simple

Lees onderstaande zin. Staat deze in de present continuous of in de past continuous?

My parents are leaving for Spain right now.

1. Present continuous
2. Present simple

Choose the Present Continuous:
Our teacher ___ the grammar.

1. explains
2. is explain
3. explaining
4. is explaining

Which signal word tells you that you need to use present continuous?
(You can choose more than one answer)

1. At the moment
2. Every Saturday
3. Now!
4. Often

Grammar - Conjunctions

Reading 

There are three reading strategies :

• Predictability
  
•  Structure visibility
  
•  Redundancy
  

Why do you first scan the text?

How do you find the main idea of the text?

Why are conjunctions important?

Go to Exercise 3 and complete the reading exercise

Exercise 3- Answers

1. What is the difference between AC and DC power?

• AC power = Alternating current, which changes direction periodically. The voltage in AC circuits also periodically reverses because the current changes direction.
  
• DC power = direct current, the electric charge (current) only flows in one direction
  

2. Name three power sources in the plane:

1. DC battery power
   
2. Engine driven generating power
   
3. Ground power
   

Exercise 3- Answers

3. What are the functions of the main aircraft battery?

To supply the power for DC loads while the aircraft is on the ground

In the air, it supplies standby system power. This includes power to all components required to deploy the ram air turbine (RAT).

 

4. How many connectors do typical transport aircraft batteries have?

Two

 

5. How are status monitoring and control signals powered?

By the AC throughout the small electrical connector.

Exercise 3- Answers

6. How are most battery chargers protected from overheating?

With a series of relays and a battery thermal switch

Exercise 3- Answers

1. Redundancy = overbodigheid, overmaat, meervoudigheid
   
2. Ability = vaardigheid / vermogen
   
3. Failure = falen
   
4. Require = nodig hebben
   
5. To supply = voeden / voorzien van
   
6. Fittings = fittingen, hulpstukken
   
7. To remove = verwijderen
   
8. Configurations = configuraties
   
9. Bus system = bussysteem
   

Exercise 4 

1. What is the main function of the DC generator?

2. How many main AC generators are usually onboard a plane? What other kind of AC generators are also available?

3. What kind of systems does the AC generator supply with power (name at least three)?

4. How many AC generators do you need to supply enough electrical power to sustain all necessary electrical systems?

5. Which two systems control the electrical power in the airplane, and what is their function?

6. What is a solenoid?

7. What kind of sensors does the BPCU use to monitor the system?

8. Explain in your own words how the BPCU uses sensors to monitor the system.

Exercise 4 - Answers

1. What is the main function of the DC generator?

It may be used to supply emergency power in case of multiple failures. 

2. How many main AC generators are usually onboard a plane? What other kind of AC generators are also available?

Two main generators, but the APU also drives an extra AC generator, which is available during the flight if one of the main generators fails. There is also a fourth generator, driven by an emergency ram air turbine, in case the two main generators and one auxiliary generator fail. 

3. What kind of systems does the AC generator supply with power (name at least three)?

Lighting, audiovisual systems, galley power for food warmers and beverage coolers, flight control systems, electronic engine controls, communication, and navigation system. 

Exercise 4 - Answers

4. How many AC generators do you need to supply enough electrical power to sustain all necessary electrical systems?

One (but a second one is used to share the electrical loads and provide redundancy). 

5. Which two systems control the electrical power in the airplane, and what is their function?

Generator Control Unit (GCU) is used for control of AC generator functions, such as voltage regulation and frequency control. ​

Bus Power Control Unit (BPCU) is used to control the distribution of electrical power between the various distribution of electrical power between the various distribution busses on the aircraft. 

Exercise 4 - Answers

6. What is a solenoid?

An electrical contactor connects the electrical power to the main generator bus. 

7. What kind of sensors does the BPCU use to monitor the system?

Remote current sensors known as current transformers (CT) 

8. Explain in your own words how the BPCU uses sensors to monitor the system.

As AC power flows through the main cables, the CT receives an induced voltage. The amount of CT voltage is directly related to the current flowing through the cable. The CT connects to the BPCU, which allows accurate current monitoring of the system. 

Exercise 5- Speaking

There are six different types of batteries, namely:

• Primary cell batteries
  
• Secondary cell batteries
  
• Dry charged (flooded) lead acid batteries
  
• Valve-regulated (sealed) lead-acid batteries (VRLA)
  
• Nickel Cadmium (NICD) batteries
  
• Lithium ion batteries
  

Exercise 5- Speaking

You are going to finish a chart with information about six different types of batteries. 

• Divide in groups of three (group A, B and C) 
  
• You should divide the six types of batteries over the three different people in your group.

So each person should look up the information about two different types of batteries

•  After 10 minutes you are going to hold a pitch, in which you tell your group mates how the battery works, what kind of systems it supports and what the advantages and/or disadvantages are of the battery. 
  
•  While listening to you, your group members are going to fill in their chart below. 
  
•  At the end of all the pitches, you should all have a complete chart.
  

What is the difference between AC and DC power?

What kind of generators are there in a plane, and what is their function?

What kind of systems are used to check that the generators are working well?