M6.11 Electrics Flashcards
What is a cable/wire
an isolated single solid conductor, or stranded conductor, surrounded by insulation
What are cables normally made of
Copper or aluminium
What are the advatantages of aluminium wires
Lightweight
Cheaper
What are the advantages of copper wires
Copper can hold a higher current
Aluminium wires cannot go below 8 AWG else they become brittle and crystallise
What are the two essential things that a wire has to be
Reliable
Carry a specific load
What is wet arc tracking
assessing the resistance to failure of cables when contaminated
Hence why cables lay above pipes that contain fluid
How does fluid contamination effect wires
Corrodes the insulation working it’s way to the conductor, slowly working its way up the whole cable
What does AWG mean and how does it work
American wire gauge (diameter of the cable)
The bigger the number the smaller the cable
Largest = 0AWG
What do we assume that a wires resistance is
0
What happens to the resistance if you increase the wire diameter
Resistance decreases
What happens to resistance if you increase the length of a wire
Resistance increases
What do the last two digits mean on a cable rating identification
The size (AWG)
Copper - AN-10
AL-22
Can a single wire or a loom carry for current and why
A single wire
A look has to carry less because of the heat that would be produced, but not able to disparate away
Is the voltage drop allowed bigger for a continuous or immediate drop
Voltage allows for an immediate drop is larger.
What is the voltage rating on an aircraft
600V
What are the three types of cable used on aircraft
Aurcfram
Interconnect
Equipment
What is a shielded cable
Has one or more insulated strands that are overlayed with metallic (dielectric) braided shield that
cancels out interference
What are high tension cables used for
high voltages for Engine and egnition systems
What should you not do after high tension cables have been used
Touch them, wait 10-15 mins for energy to dissipate
What are thermocouples made out of
Cromel or alumel
How does a thermocouple work
Comprised of two different metals, an electric current will flow through the thermocouple when the two junctions are at different temperatures.
What are co axial cables used for
For Radio Frequency (RF) energy which is guided from one point to another
How many conductors do co axial cables contain
2 conductors which means they are not as bendy and prevents interference
What is the timing for a fire proof cable
15 mins
