AGK Electrics Flashcards
1
Q
Pilots side Skimattic diagram
A
BAT 1 BAT 2
DC BAT
\_\_\_\_\_\_\_\_\_\_\_\_|
DC 1 |
| DC ESS
TR 1
| AC ESS
AC 1 \_\_\_\_\_\_\_\_\_|
|
GEN 1
2
Q
F/O side Skimattic diagram
A
DC 2 | TR 2 | AC 2 | GEN 2
3
Q
An aircraft electrical system provides…
A
Electrical energy uses by electrical components
4
Q
Components are known as what 2 things:
A
Current consuming devises (consumers)
Loads
5
Q
Voltage =
A
Electrical potential difference across two points in a circuit
6
Q
Current =
A
Electron flow measured in amps
7
Q
Resistance can only be found in
A
DC circuits
8
Q
Impedance =
A
AC current resistance
9
Q
Capacitance =
A
The ability to store charge
10
Q
Electric current is produced when _____ flow in an orderly way through a _____
A
Electrons
Conductor
11
Q
Current only flows when a circuit is _____ or _____
A
Complete
Closed
12
Q
Consumers/Loads can only be powered when a _____ is _____
A
Current
Flowing
13
Q
Friction produces
A
Static electricity
14
Q
Light aircraft usually have a __ volt __ system
A
14
DC
15
Q
Larger twin turbine aircraft usually have a __ volt __ system
A
28
DC
16
Q
Modern jet airliners usually have a ____ __ system at a frequency of ____
A
115v/200v AC
400Hz
17
Q
A conductor is any _____ which readily allows _____ _____ to flow through it
A
Material
Electrical current
18
Q
An atom consists of:
A
Protons
Electrons
Neutrons
19
Q
Electrons that jump from one atom to another are know as
A
Free electrons
20
Q
When atoms have more electrons than protons they are
A
Negatively charged
21
Q
When an atom’s electrons does not equal the number of protons it is know as an
A
Ion
22
Q
Materials that have tightly bound _____ which resist movement between _____ cannot easily _____ electrical current are called ____
A
Electrons
Atoms
Conduct
Insulators
23
Q
Materials that have _____ that move easily from atom to atom are know as _____
A
Electrons
Conductors
24
Q
Batteries have _____ and _____ terminals
A
Positive
Negative
25
A positive battery terminal is called an
Anode
26
A negative battery terminal is called a
Cathode
27
The diffrence in charge between a positive and a negative terminal is the _____ _____ or the _____ _____
```
Electric potential
Electromotive force (EMF)
```
28
In a closed circuit
Current flows
29
In an open circuit
No current flows
30
It was assumed that electrons travel from positive to negative, this is known as _____ _____. When actually electrons traveling from negative to positive known as _____ _____
Conventional flow
| Electron flow
31
Ohm's Law:
V=IR
32
Electrons have
Magnetic fields
33
Lorentz Law
F=BLI
```
F = force
B = flux density
L = length of cable
I = Current
```
34
Capacitance
The ability of a circuit to store an electric charge or electrical energy
35
Capacitor
An electrical device used to store electrical energy
36
A capacitor have two _____ _____ separated by a thin insulating materiel know as a _____
Conductive plates
| Dielectric
37
Capacitance is determined by 3 things:
The area of the plates
The distance between the plates
The dielectric constant of the dielectric
38
The dielectric constant measures the _____ of the dielectric when compared with that of a _____
Effectiveness
| Vacuum
39
C= _/_
c=q/v
```
c = capacitance
q = charge
v = voltage
```
40
Resistance
the opposition to current flow on a circuit
41
Resistance is determined by 3 factors:
The type of material (amount of free electrons)
Cross section area
length
42
Every _____ in a circuit will have _____
Consumer
| Resistance
43
If a resistor in a _____ circuit fails, the whole circuit will _____
Series
| Fail
44
Adding resistors in a series circuit
Rt = Rt1 + Rt 2 + Rt3
45
Adding resistors in a parallel circuit
1/Rt = 1/Rt1 + 1/Rt2 + 1/Rt3
46
When temperature increases, resistance will _____
Increase
47
Thermistors
Resistors that respond to changes in temperature
48
When resistance increases with increasing temperature the material has a
Positive temperature coefficient
49
When resistance decreases with increasing temperature the material has a
Negative temperature coefficient
50
Automatic control can be achieved by what 2 switches?
Thermo switches
| Time switches
51
Thermo switches are _____ sensitive. Made of a _____ strip which is sensitive to _____ _____
Temperature
Bi-metallic
Current flow
52
Toggle switches have a protruding operating _____ and can have _ or _ selectable positions
Lever
| 2 or 3
53
Rotary switches are used for _____ functions by changing _____ in a circuit
Dimmer
| Resistance
54
Push switches may incorporate an _____ _____
Illuminated Caption
55
Pole is the _____ part of a switch
Connecting
56
Throw is the _____ part of a switch
Moving
57
Batteries provides a store of _____ _____ to start the engine or APU and to power _____ services in the event of generator or alternator _____
Electrical power
Emergency
Failure
58
Two types of batteries:
```
Lead Acid
Nickel Cadmium (NiCd)
```
59
Light aircraft have ______ batteries
Lead acid
60
Large aircraft have _____ batteries
NiCd
61
_____ batteries maintain their correct _____ for longer
NiCd
| Voltage
62
Normal (V)
The Benchmark voltage of 12V (minimum voltage)
63
Terminal (V)
Actual V measured at the battery terminals
64
The actual voltage provided by a battery on load will be _____ than it's normal voltage
Lower
65
The battery comprises a number of _____. Each cell is a sealed, vented container having two _____ and an _____
Cells
Electrodes
Electrolyte
66
The individual cell voltage for a lead acid cell is __ volts (____ load)
2.2
| Off
67
The Terminal voltage for a lead acid battery is ___V, made up of __ cells
12.7V
| 6
68
The individual cell voltage for a NiCd cell is __ volts (____ load)
1.3V
| On and Off
69
The Terminal voltage for a NiCd battery is ___V, made up of __ cells
12.7V
| 10
70
In lead acid battery operation, A fully charged state means the plates are
Positive - Lead dioxide
| Negative - Elemental lead
71
During discharge, Ion flow is moving from _____ to _____ causing electrical _____ within the battery
Negative
Positive
Flow
72
During the charged phase, the alternator _____ ion flow whilst 'boiling' off the _____ allowing the molecules to _____ to the water content.
Reverses
Sulphur
reattach
73
Checking: _____ voltage should be _____ whilst it is off load and then _____ with the voltage when it is on load. A large difference means that the battery is not _____ _____
Battery
Measured
Compared
Fully charged
74
If the voltmeter remains low after the Pitot heat has been turned off, that means
There is a dead battery
75
If the voltmeter jumps back up after the Pitot heat has been turned off, that means
The battery is fully charged
76
If the voltmeter steadily recovers after the Pitot heat has been turned off, that means
The battery is 50% charged
77
Re-charge the battery you should
Start the engine and run for 20 minutes
78
NiCd batteries are constructed from
Nickel Hydroxide – Positive (anode)
Cadmium Hydroxide – Negative (Cathode)
Potassium Hydroxide (electrolyte paste)
79
NiCd batteries are prone to
Battery memory and thermal runaway
80
The solution to thermal runaway is to add a _____ which reduces the _____
Battery charge limiter (BCL)
| Current
81
Capacity is the battery's ability to produce _____ for a _____ time, measued in _____
Current
Minimum
amp hours (Ah)
82
A 40Ah battery should supply ___ for ___ hour or ___ for ___ hours
40 amps
1
1 amp
40
83
Colder batteries
Decrease capacity and rate of discharge
84
Batteries in series increase/decrease
Volts
85
Batteries in parallel increase/decrease
Amps
86
An aircraft battery must provide at latest _____ of power
30 minutes
87
Hierarchy of an aircraft's power source
```
Generator (main engines)
External (ground power
APU
RAT
Batteries
```
88
```
Must power
Generator:
External:
APU:
RAT:
Betteries:
```
```
90KVA each
unlimited
90KVA
5KVA
1KVA
```
89
Magnetic fields can be generated by two types of magnet:
Permanent magnets
| Electromagnets
90
Permanent magnets are made of _____ ____. They are ____ to magnetise, but once done, retains it's _____.
Hard iron
Hard
Magnetism
91
Electromagnets only generate magnetic fields when they are placed within an _____ _____
Electric field
92
Electromagnets have a _____ _____, ferromagnetic core. They are ____ to magnetise but lose their magnetism as soon as the _____ _____ is removed.
Soft Iron
Easy
Electric field
93
When a material is fully magnetised, it is _____
Saturated
94
Red on a magnet is it's _____, and blue is it's _____
North
| South
95
The lines displaying a magnetic field are called the _____ __ _____
Lines of Flux
96
In electromagnets, using a DC charge the pole will _____ ___ _____, and using AC they will _____ at the rate of the _____
Remain the same
Switch
Frequency
97
A relay switches _____ voltage/current using _____ voltage/current
High
| Low
98
Relay circuits use _____ to close the _____. When the _____ closes, that _____ the circuit
Electromagnets
Switch
Switch
Closes
99
Benefits of a relay circuit :
Safer
Cheaper
Will not transfer faults from the AC circuits to the DC circuits
100
Induction
The process of generating an electromotive force or voltage using a magnetic field
101
Inductance
the ability of a coil to induce a voltage, increases with an increase of the number of turns of wire and if the wire is turned around a ferromagnetic core
102
Magnitude of the induced voltage depends on 3 factors:
Speed of movement of the coil
Number of turns of wire in the coil
Strength of the magnetic field
103
An AC Generator features:
```
Rotating magnet
Fixed armature (wire)
```
104
A DC Generator features:
Fixed magnet
Rotating armature (wire)
Commutator
105
A DC alternator is an extension to the __ _____, but features a _____ _____ to _____ the __ current
AC generator
Diode Rectifier
Convert
AC
106
Benefits of a DC alternator
Small
| Efficient
107
A DC Generator is a modern version of _____ _____
Faraday's Experiment
108
All generators convert _____ energy into _____ energy.
Mechanical
| Electrical
109
Stater generator
Combination of DC generator producing a DC output and a starter motor using DC to start the engine.
110
As soon as the conductor stops moving through the magnetic field...
The current flow stops
111
The sine wave plots the _____ of the _____ and the resulting _____
Movement
Conductor
Current
112
In a generator, a Brush is made of _____ and is a _____ object.
Carbon
| Fixed
113
A Slip-ring is made of _____ and is a _____ object.
Copper
| Rotating
114
The brush and the slip-ring connect a _____ component to a _____ component.
Rotating
| Non-rotating
115
Most generators are
3 phase AC
116
Modern piston engine aircraft have a __ _____
DC alternator
117
Rotor incorporates an _____ _____ and the stator forms the _____ into which the voltage is induced
Electromagnetic Field
| Coil
118
There are _ diodes in a DC alternator for every _____ in the AC Generator
2
| Phase
119
There are _ _____ for a 3 phase generator
6 Diodes
120
In a Brushless generator, a _____ _____ _____ is used for start up only. This is know as the _____ _____
Permanent magnet generator (PMG)
| Inital Excitation
121
A voltage regulator controls the _____ to the _____ _____
Current
| Electromagnetic Field
122
In a voltage regulator, the _____ remain the same and the _____ varies
Voltage
| Load
123
As engine _____ increases, field strength _____ and vice-versa. This maintains a constant _____.
Output (RPM)
Decreases
Voltage
124
There are 2 types of voltage regulator:
```
Carbon pile (linear)
Solid state switch mode
```
125
Carbon pile regulators tend to be found in very _____ _____
Old aircraft
126
In a carbon pile regulator, _____ through the Carbon stack is _____ to compression. The more the _____, the lower the _____
Resistance
Proportional
Compression
Resistance
127
In a DC generator, AC is converted into DC by a _____ _____ _____ and _____ _____
Split ring commutator
| Carbon brushes
128
DC generators have poor _____ at low ___ because of the commutator and _____ at the carbon brushes
Output
RPM
Sparking
129
DC alternator overcomes those two disadvantages and
| provides a better...
Power to weight ratio
130
A cutout relay prevents....
The generator from becoming a motor
131
The generator cut-out automatically disconnects the generator when generator voltage _____ below _____ _____
Falls
| Battery voltage
