6.11 Flashcards
What is the definition of a wire?
An isolated single conductor surrounded by insulation
What is the definition of a cable?
A group of two or more conductors
When is aluminium conductor used?
For large loads to save weight
What are the three different categories of wires?
- normal
- high temperature
- fire resistant
What temperature do normal wires cover?
Up to 150°C
What temperature do high temperature wires go up to?
Up to 250°C
What temperature do fire resistant wires go up to?
Up to 400°C
When are shielded wires used?
To protect against any outside erratic signals or magnetic interference
Where is the shielded wire grounded if it is below 50KHz?
At one end
Why is ARINC 429 data bus different?
It is grounded on both ends
When are coaxial cables used?
To transport high frequency signals
What side is grounded on coaxial cables?
Both sides
What is printed on a wire or a cable?
It’s part number
What does class mean in a wiring material specification?
The amount of insulated wire in the cable
How often is the print on a wire replicated?
150-500mm
What does wire identification markings contain?
A combination of numbers and letters to show what circuit it belongs to
Where can wire size and other information on that wire be found?
A wiring diagram
If wire and cable marking cannot be completed without insulation damage, what should be used?
Insulation tubing printing
When is vertical printing used?
The wire is very small or thin insulation
Why is aromatic polyamide insulation used?
It saves 50% weight and 30% space and high temperature resistance
How does dry carbon arc tracking work?
A build up of carbon from damaged insulation which then can have the ability to short circuit
How does wet carbon arc tracking work?
When a breakdown of insulation gets contaminated with fluid causing a short circuit
What is the temperature range of a fire warning wire?
Up to 400°C with a fire resistance of 1,093°C for 5 minutes
What colour are fire warning wires?
Normally red but can be white
How do you decide to install pins or sockets at a connector?
By establishing which side is live
Why is the live side of a connector normally have socket type contacts?
To minimise the risk of electrical shock
What are the two types of connectors?
Split shell and assembled construction
What are split shell connectors made from?
Aluminium
Why are class K split shell connectors special?
They’re fireproof connectors made from steel
What comes separate when ordering an assembled connector?
The backing clamp
What is the job of a back shell in a connector?
To provide support for the wires
Where is the master key-way located if a connectors is installed on the horizontal axis?
At the top
Where is the master key-way located if a connectors is installed on the vertical axis?
Forward in relation to the aircraft
How are the connector contacts denoted?
By letters, numbers, or combination of both
How are connector contacts layer outed?
Starting at the centre and spiralling anti-clockwise outwards
When denoting connector contacts with letters what is the order when you have more than 24?
- upper case letters
- lower case letters
- double upper case letters
When numbers or letters are removed to prevent confusion in connector contacts, what is done?
It is marked by a small slash
If a connector contact is not used what must happen?
It must be filled with nylon or Teflon seal plugs
When are polarisation keys used?
When preventing the wrong computer being inserted into a shelf
When must non self-locking threaded couplings be wire locked?
In areas inaccessible for regular maintenance inspections and high vibration areas
What size locking wire must be used to safety an electrical connector?
0.5mm
