Protection Devices and Misc
Why do crimpers used on aircraft wire have a ratcheting mechanism?
So they don't release until the proper crimp pressure has been achieved.
An electrical switch is used to:
Open and close a complete circuit
What does this mean? DPDT
Double Pole, Double Throw
The only type of conductor approved for splicing.
Copper
Why don't we use solder in aircraft wiring?
Because it will become brittle with vibration and not create a good connection.
What does this mean? SWAMP
Severe Wind and Moisture Problem
This kind of wire is especially vulnerable if it's nicked
What is aluminum wire?
Intermittent operation means that a system is not on for more than how long?
Two minutes
This type of wire should never be smaller than 8 gauge.
Aluminum.
Aircraft fuse capacity is rated in:
Amperes
What are the three types of electromagnetic switches?
Solenoid / Relay / Contactor
Define intermittent duty circuit.
A circuit that is in operation 2 minutes or less at a time.
Minimum distance a splice must be from a termination device.
12 inches
Which size wire is a yellow ring terminal used for?
10-12 gauge.
Maximum interval between identification markings:
15 inches
What type of tool should never be used to install a terminal on an aircraft wire?
Pliers.
A coaxial cable should be routed:
As directly as possible.
What are junction boxes in a fire zone usually made of? How should junction boxes never be installed?
Stainless steel. In such a way as to retain anything that's dropped from above.
A circuit breaker primarily protects:
Wiring from too much current
What do we mean by derating a switch?
Choosing a switch with more capacity than the circuit it controls, to ensure longer service life.
Define what nominal rating refers to and what it means.
It refers to switches and means the continuous current rating with contacts closed.
Maximum number of splices permitted between any two connectors.
One
What is a type of electrical installation that must be protected against rotation?
The installation of terminal rings/lugs on a terminal stud.
The discharge of electricity at higher potentials is called:
What is the minimum bend radius for a wire bundle?
Ten times the outside diameter of the largest wire in the bundle.
An AWG number pertains to the size of a wire according to its:
Cross-sectional area / diameter / width
How should a wire bundle be routed relative to a fuel line?
Above and not parallel unless necessary.
It's the minimum number of strands wiring is permitted to have.
What do the terms throw and pole mean regarding switches?
The throw number of a switch indicates the number of current carrying positions it can have. The number of poles indicates the number of circuits that can be activated.
If a light switch is connected in series to more than one light, but the lights are parallel to each other, how will the circuit operate when the switch is closed?
All of the lights will come on. If one light burns out, the others will continue to work.
In a wire bundle, how should several splices be arranged?
Staggered along the length of the bundle
Why is there a hole on the side of a pin or socket connector? What is it called?
To ensure the wire is all the way in the contact. An inspection hole.
Provides mechanical protection to wires. Metallic or not, rigid or flexible.
Conduit
This is the manufactured property of wire that has to do with its insulation.
Dielectric strength.
The purpose of including a diode in a relay or solenoid.
Remove current spikes
(Anti-spiking diode)
Describe a coaxial cable. What does it usually connect?
A single conductor surrounded by an insulator, then surrounded by a braided metal conductor covered with insulation. An antenna to a radio.
If wire is installed where it could come in contact with moving parts, what must be done?
It must be enclosed in a conduit.
How do you test a solenoid?
When are guarded switches used?
When inadvertent operation of the switch could endanger a system, or when the switch is only used in an emergency.
The side of the circuit on which a pin (male) section of an AN/MS connector should be installed.
The ground side
What is the significance of the number four regarding terminal strips?
It's the max number of ring terminals and/or bus bars permitted to be stacked on one terminal stud.
The two fundamental properties of insulation:
Insulation resistance and dielectric strength
A suitable grommet.
Bonding connections should be tested for:
Resistance value
What is something that happens when a current flows through a conductor, that must be protected against?
An electromagnetic force is created which induces a current in other wires.