Airframe VI Electricity (Chapter 9)

inversely

Basically, Ohm’s Law states that the current (electron flow) through a conductor is directly proportional to the voltage (electrical pressure) applied to that conductor and ______________proportional to the resistance of the conductor.

motivated (9-2)

These loosely bound electrons are easily _______________to move in a given direction when an external source, such as a battery, is applied to the circuit.

equalized (9-3)

If the valve in the interconnecting line between the tanks is opened, water flows from tank A into tank B until the level of water (potential energy) of both tanks is_____________.

piezoelectric effect (9-4)

Using pressure to generate electrical power is commonly known as the____________________.

current (9-5)

Remember voltage (electrical pressure) must be present to produce a __________(electron flow).

magnetic field (9-6)

Therefore, for explanatory purposes, the action of either conductor, A or B, while rotating in the _________________is similar to the action of the loop.

alternating (9-8)

AC is constantly changing in value and polarity, or as the name implies, _______________.

360° (9-9)

It should be noted that the time period of a cycle can change from one system to another; it is always said that the cycle completes in ________.

two voltages (9-10)

The phase relationship can be measured between ________________of different alternators or the current and voltage produced by the same alternator.

capacitors (9-11)

Since AC constantly changes direction and intensity, inductors and ______________may also create an opposition to current flow in AC circuits.

one direction (9-39)

The operation of a zener diode is similar to a common diode in that the zener only permits current flow in______________.

three (9-40)

For each revolution of the alternator, the unit produces _________ separate voltages.

stationary (9-41)

The pilot exciter armature is mounted on the _____________ part of the assembly.

constant (9-43)

If the aircraft engine changes speed, the alternator speed remains_______________.

output frequency (9-44)

Unlike DC systems, AC systems must ensure that the __________________ of the alternator stays within limits.

GCU (9-45)

When the pilot selects the operation of an AC alternator, the ______ monitors the alternator’s output to ensure voltage and frequency are within limits.

open circuit (9-46)

An _______________ is an electrical fault that occurs when a circuit becomes disconnected.

armature (9-47)

The generator output current is supplied to the aircraft bus through the ___________ circuit (A terminal) of the generator.

External power (9-48)

___________________ is often used for starting the engine or maintenance activities on the aircraft.

aircraft battery (9-49)

During most typical operations, the starter is powered by the___________________.

wired in series (9-50)

A typical avionics power switch is shown _________________ with the avionics power bus.

up-limit switches

The three ____________________ are used to detect when the gear reaches the full retract (UP) position.

squat switch (9-53)

The ____________ is used to determine if the aircraft is on the GROUND or in FLIGHT.

paralleling (9-56)

Today’s aircraft employ solid-state control circuits to ensure proper ____________ of the alternators.

heaviest current loads (9-57)

So the main battery bus must be large enough to carry the ________________ of the aircraft.

positive (9-59)

The diode is placed in the circuit so the main bus must be more _________ than the sub bus for current flow.

contactors (9-60)

After generator power is available, the BPCU activates various ______________ to distribute the electrical power.

together (9-61)

During normal flight conditions, all engine-driven generators connect ____________ and power the AC loads.

generator failure (9-62)

One advantage of parallel systems is that in the event of a___________________, the buses are already connected and the defective generator need only be isolated from the system.

catastrophic (9-63)

The DC power systems are the final backups in the event of a   ____________ electrical failure.

knowledge and techniques (9-64)

The continued proper performance of electrical systems depends on the ____________________________ of the technician who installs, inspects, and maintains the electrical system wires and cables.

severe environmental (9-66)

Wire construction that is suitable for the most _______________________________ condition to be encountered should be selected.

high-temperature equipment (9-79)

Wiring must be routed away from ___________________________ and lines to prevent deterioration of insulation.

protection (9-80)

Wiring which must be routed in wheel wells or other external areas must be given extra _________________ in the form of harness jacketing and connector strain relief.

24 inches

They should be spaced at intervals not exceeding _______________.

25 percent larger (9-82)

Conduit size should be selected for a specific wire bundle application to allow for ease in maintenance, and possible future circuit expansion, by specifying the conduit inner diameter (ID) about _______________ than the maximum diameter of the wire bundle.

affected (9-84)

A wire is normally shielded when it is anticipated that the circuit can be ______________ by another circuit in the wire harness.

continued airworthiness (9-85)

Criteria for inspection and maintenance to ensure ___________________ throughout the expected life of the aircraft should be established.

SWAMP (9-86)

Straps may not be used in areas of____________, such as wheel wells, near wing flaps, or wing folds.

12 inches

Use wire group or bundle ties where the supports for the wire are more than __________ apart.

Terminal blocks (9-90)

___________________ should be provided with adequate electrical clearance or insulation strips between mounting hardware and conductive parts.

same material (9-91)

Replacement junction boxes should be fabricated using the ________________ as the original or from a fire-resistant, nonabsorbent material, such as aluminum, or an acceptable plastic material.

pressure seal

Hermetic connectors provide a _____________________ for maintaining pressurized areas.

separate connectors (9-94)

It is also good practice to route a system’s indication wiring in __________________ from its failure warning circuits to the extent practicable.

severely damaged (9-95)

Coaxial cable can be _________________ on the inside without any evidence of damage on the outside.

become open (9-97)

The contacts of the NC switch are connected in the normal position and ______________ when the switch is activated.

two switch positions (9-98)

The coil current can be on or off so relays have__________________.

open the circuit (9-99)

All resettable circuit breakers should _________________ in which they are installed regardless of the position of the operating control when an overload or circuit fault exists.

position lights (9-100)

A set of _________________ consist of one red, one green, and one white light.

rotating mirrors (9-101)

The light may be fixed but mounted under ______________ inside a protruding red glass housing.

landing light (9-102)

Many small aircraft are not equipped with any type of taxi light, but rely on the intermittent use of a ______________ to illuminate taxiing operations.

visual detection (9-103)

These lights permit ______________ of ice formation on wing leading edges while flying at night.

electromagnetic interference (9-67)

Shielding is the process of applying a metallic covering to wiring and equipment to eliminate ____________ (EMI).

equal to (9-68)

The temperature of the wire rises until the heat radiated, or otherwise dissipated, is __________ the heat generated by the passage of current through the line.

current rating (9-70)

When aluminum conductor wire is used, sizes should be selected on the basis of __________ shown.

voltage drop

To determine circuit resistance, check the __________ across the circuit.

type identification (9-76)

All wire used on aircraft must have its __________ imprinted along its length.

identification tape (9-76)

In most cases, __________ can be used in place of sleeving.

sufficient slack (9-78)

Wiring should be installed with _________ so that bundles and individual wires are not under tension.

Wires connect all the components in an electrical system to one another and turn the electrical system on and off. FALSE

True or False: Wires connect all the components in an electrical system to one another and turn the electrical system on and off.

Gauge

Which of the following is defined as the measurement of a wire's thickness?

The battery supplies a charge of energy that helps to start the engine and provides backup to the electrical system. TRUE

True or False: The battery supplies a charge of energy that helps to start the engine and provides backup to the electrical system.

Alternator

Which component of the electrical system recharges the battery and keeps the electrical system running?

Voltage regulator

Which component of the electrical system keeps the flow of electricity constant?

An electrical circuit is a line of electrical components starting from the bus, which includes circuit protection devices, switches, wires, and the load. TRUE

True or False: An electrical circuit is a line of electrical components starting from the bus, which includes circuit protection devices, switches, wires, and the load.

Any part or system that needs electricity to operate

Which of the following defines load?

Unlike a circuit breaker that can be reset after an electrical surge, a fuse is destroyed and will need to be replaced. TRUE

True or False: Unlike a circuit breaker that can be reset after an electrical surge, a fuse is destroyed and will need to be replaced.

Ammeter

Which component of the electrical system measures the amount of electricity flowing in the system and is located in the cockpit?

Electrical short

What event occurs when two circuits become joined, which creates a new path for electricity to follow and often produces an uncontrolled electrical discharge?

Electrostatic discharge

What event creates interference in airplane systems that use radio frequencies?

Sparking

Which of the following is not a way to control electrostatic discharge?

Grounding

Which of the following controls for electrostatic discharge allows the electricity to flow back to its point of origin or source to complete the circuit.

Static wick

Which of the following is a device made of wire wrapped in a flexible or rigid plastic tube attached to the trailing edges of the airplane?

Lightning strike protection is a conductive material that works with the static wicks to create one path designed to dissipate energy. TRUE

True or False: Lightning strike protection is a conductive material that works with the static wicks to create one path designed to dissipate energy.

Bonding Strap

Which of the following is a conductive material that provides a ground path between the equipment and the shock mount?

Bonding the equipment ensures the unwanted electricity will discharge to the equipment, rather than discharging to the airplane. FALSE

True or False: Bonding the equipment ensures the unwanted electricity will discharge to the equipment, rather than discharging to the airplane.

Electrical system

A(n) ________ is a series of wires and other components that provide electricity throughout an airplane.

The master switch is located in the cockpit of the airplane. TRUE

True or False: The master switch is located in the cockpit of the airplane.

Wires

________ are used to connect all the components in an electrical system to one another and distribute electricity to the entire system.

American wire gauge

The size of the wire is measured using the ________ (AWG) systems.

Battery

A(n) ________ contains reactive cells that store energy. When activated, a(n) ________ converts this stored energy into electricity.

An alternator can also be called a generator. TRUE

True or False: An alternator can also be called a generator.

Circuit breaker; Fuse

When the electrical system receives a surge of electricity, a ________ or ________ protects the system by stopping electricity from entering the circuit.

Navigation systems

Three types of airplane equipment are prone to interference from any electrostatic discharge: antennas, radios, and ________.

Grounding

Three common practices for controlling electrostatic discharge are ________, bonding, and static wicks.

Airframe

In an airplane, circuits are grounded to the ________. Any electrical energy spikes that occur can be directed to discharge points on the airplane. This energy is then discharged into the atmosphere.

Interference

Some components, such as the antennas, are intentionally not bonded to the airframe because this would cause ________ with the radio systems.

Shock mount

A ________ is a mounted device that connects equipment to a rack or stand to absorb vibrations.

Bonding

________ is the practice of intentionally connecting electrically all of the metallic, noncurrent-carrying items in an airplane.

A busbar conducts electricity and distributes large amounts of electricity to the electrical circuits. TRUE

True or False: A busbar conducts electricity and distributes large amounts of electricity to the electrical circuits.

Modern commercial airplanes use wire for everything from controlling the airplanes movements to entertaining the passengers. TRUE

True or False: Modern commercial airplanes use wire for everything from controlling the airplanes movements to entertaining the passengers.

A metal conductor and non-metallic insulation

What are electrical wires composed of?

The metal conductor provides a one-way path for the electrical current to move from an electrical power source to a power user. TRUE

True or False: The metal conductor provides a one-way path for the electrical current to move from an electrical power source to a power user.

Prevent the transmission of electricity

Insulation is made from materials that ________.

Electromagnetic field

What is the name of the area of forces that electrical currents create around the conductor?

Electromagnetic interference

When two conductor fields are brought close together, the field around one conductor may interfere with the current flowing through the other. What is this called?

Class 1 wire

There are two classes of wire used on an airplane. The ________ is resistant to hydraulic fluid and is used in areas such as the landing gear or wings.

Class 2

There are two classes of wire used on an airplane. Which class of wire is not resistant to hydraulic fluid and is used in areas where it would not be in contact with hydraulic fluid?

Grade A

There are four temperature grades into which wires are divided. Which grade has a 212 F maximum temperature?

When the wire grade is specified on a drawing or in a specification, only that grade of wire, or a grade with a lower maximum temperature, may be used. FALSE

True or False: When the wire grade is specified on a drawing or in a specification, only that grade of wire, or a grade with a lower maximum temperature, may be used.