AF Aircraft Electrical Systems

Some electric motors have two sets of field windings wound in opposite directions so that the

One purpose of a growler test is to determine the presence of

Electric wire terminals for most aircraft applications must be what type?

What is the principal advantage of the series-wound DC motor?

If a generator is equipped with a vibrator-type voltage regulator, the actual time the voltage regulator points remain open

What is a cause of generator brush arcing?

What is required when operating two aircraft AC generators in parallel?

The starting current of a series-wound DC motor in passing through both the field and armature windings produces a

Which motor would be most likely to have an armature brake?

The method most often used in overcoming the effect of armature reaction is through the use of

The only practical method of maintaining a constant voltage output from an aircraft generator under varying conditions of speed and load is to vary the

The pole pieces or shoes used in a DC generator are a part of the

How many cycles of AC voltage are produced in a six-pole alternator of the revolving-field type for each revolution of the rotor?

If the reverse current cutout relay contact points fail to open after the generator output has dropped below battery potential, current will flow through the generator armature

How does the magnetic brake used to stop the rotation of an electric motor armature operate?

In a generator, what eliminates any possible sparking to the brush guides caused by the movement of the brushes within the holder?

A series-wound DC electric motor will normally require

The type of electric wire terminals used for most aircraft applications, in addition to providing good current carrying capabilities, are designed primarily

Aluminum wire must be stripped very carefully because

The commutator of a generator

An ammeter in a battery charging system is for the purpose of indicating the

Which of the following is not one of the purposes of interpoles in a generator?

To test generator or motor armature windings for opens.

What is the color and orientation for the position lights for navigation on civil airplanes?

A voltage regulator controls generator output by

Which type of DC generator is not used as an airplane generator?

What is the most accurate type of frequency measuring instrument?

During ground operation, aircraft generator cooling is usually accomplished by

What does a rectifier do?

What type of instrument is used for measuring very high values of resistance?

To what depth is the mica insulation between the commutator bars of a DC generator undercut?

When a diode is checked for an open circuit or a short circuit, it should be

When handling a high voltage capacitor in an electrical circuit, be sure it

Which of the following is most likely to cause thermal runaway in a nickel-cadmium battery?

How can it be determined if a transformer winding has some of its turns shorted together?

Which of the following are the major parts of a DC motor?

(1) There are three basic types of DC motors; series, short, and compound.

(2) In the series motor, the field windings, consisting of relatively few turns of heavy wire, are connected in series with the armature winding.

Regarding the above statements,

What is the appropriate method for installing pre-insulated terminal lugs and splices to electric wires?

Which of the following factors must be taken into consideration when determining the wire size to use for an aircraft installation?

When selecting hardware for attaching bonding connections to an aircraft structure, which of the following should be considered?

How should the splices be arranged if several are to be located in an electrical wire bundle?

What is the minimum bend radius for an electrical wire bundle?

When approved, splices may be used to repair manufactured harnesses or installed wiring. The maximum number of splices permitted between any two connections is

Electrical connectors used in aircraft assemblies should meet which of the following specifications?

The most common method of attaching a pin or socket to an individual wire in an MS electrical connector is by

The pin section of an AN/MS connector is normally installed on

The voltage output of an alternator may be regulated by controlling the

If several long lengths of electrical cable are to be installed in rigid conduit, the possibility of damage to the cable as it is pulled through the conduit will be reduced by

Grounding is electrically connecting a conductive object to the primary structure. One purpose of grounding is to

What is normally used to bond noncontinuous stainless steel aircraft components?

Aircraft fuse capacity is rated in

When adding a rheostat to a light circuit to control the light intensity, it should be connected to

Circuits that must be operated only in an emergency or whose inadvertent activation could endanger a system frequently employ

If one switch is used to control all navigation lights, the lights are most likely connected

Oil canning of the sides of aluminum or steel electrical junction boxes is considered to be

Electric wiring installed in aircraft without special enclosing means (open wiring) offers the advantages of ease of installation, simple maintenance, and reduced weight. When bundling open wiring, the bundles should

During inspection of the terminal strips of an aircraft electrical system, it should be determined that

What protection to wires and cables does conduit provide when used in aircraft installations?

Which of the following should be accomplished in the installation of aircraft wiring?

If the (+) terminal of a voltmeter is connected to the (-) terminal of the source voltage and the (-) terminal of the meter is connected to the (+) terminal of the source voltage, the voltmeter will read

When using the voltage drop method of checking circuit resistance, the

The nominal rating of electrical switches refers to continuous

Aircraft electrical junction boxes located in a fire zone are usually constructed of

To help minimize radio interference a capacitor will largely eliminate and provide a steady direct current if the capacitor is connected to the generator in

The primary considerations when selecting electric cable size are

The navigation lights of some aircraft consist of a single circuit controlled by a single switch which has an ON position and an OFF position, with no additional positions possible. This switch is referred to as a

Electric circuits are protected from overheating by

How should a coaxial cable be routed?

Which of the following copper electric cable sizes should be selected to replace a No. 6 aluminum electrical cable?

In installations where the ammeter is in the generator or alternator lead, and the regulator system does not limit the maximum current that the generator or alternator can deliver, the ammeter can be redlined at what percent of the generator or alternator rating?

Which statement relating to electric wiring is true?

Bonding connections should be tested for

What kind of switch should you install in a single wire circuit that required the switch to be manually held in the ON position?

A circuit breaker is installed in an aircraft electrical system primarily to protect the

How should a voltmeter be connected?

A circuit protection device called a current limiter is essentially a slow-blow fuse and is designed to be used in

If it is necessary to use an electrical connector where it may be exposed to moisture, the mechanic should

Which of the following are considered circuit-protective devices that are used in aircraft electrical systems?

If a wire is installed so that it comes in contact with some moving parts, what protection should be given the wire?

In the American Wire Gauge (AWG) system of numbers used to designate electrical wire sizes, the number assigned to a size is related to its

What is the voltage drop for a No. 18 copper wire 50 feet long to carry 12.5 amperes, continuous operation?

Use the formula VD = RLA

VD = Voltage drop
R = Resistance per ft. = .00844
L = Length of wire
A = Amperes

What is the purpose of the selection of derated switches for known continuous load current applications?

What is the advantage of a circuit breaker when compared to a fuse?

What is the advantage of a current limiter?

What should be used to protect wires from chafing when they must pass through bulkheads, firewalls, ribs, etc.?

In aircraft electrical systems, automatic reset circuit breakers

A certain switch is described as a single-pole double-throw (SPDT) switch. The throw of a switch indicates the number of

When considering an alteration, the criteria upon which the selection of electric cable size should be based are

What is an important factor in selecting aircraft fuses?

The circuit breaker in the instrument lighting system protects the

One advantage of using AC electrical power in aircraft is

Why are the iron cores of most induction coils laminated?

Certain transport aircraft use AC electrical power for all normal operation and battery furnished DC electrical power for standby emergency use. In aircraft of this type that operate no DC generations, the batteries are kept charged by

The voltage in an AC transformer secondary that contains twice as many loops as the primary will be

If the positive field lead between a generator and a generator control panel breaks and is shorted while the engine is running, a voltmeter connected to generator output would indicate

What is a method used for restoring generator field residual magnetism?

The major advantages of alternating current (AC) over direct (DC) is the fact that its current and voltage can easily be increased or decreased.

Which of the following must be accomplished when installing an anti-collision light?

The inductor-type inverter output voltage is controlled by the

When using an ohmmeter to check the continuity of a generator field coil, the coil should

The strength of the core of an electromagnet depends upon the material from which it is constructed and which of the following?

A voltage regulator controls generator voltage by changing the

The overvoltage control automatically protects the generator system when excessive voltage is present by

When DC generators are operated in parallel to supply power for a single load, their controls include an equalizer circuit to assure that all generators share the load equally. The equalizer circuit operates by

What is the maximum amount of time a circuit can be in operation and still be an intermittent duty circuit?

The most common method of regulating the voltage output of a compound DC generator is to vary the

Refer to Figure 18. Which of the batteries are connected together incorrectly?

Refer to Figure 19. Upon completion of the landing gear extension cycle, the green light illuminated and the red light remained lit. What is the probable cause?

If any one generator in a 24-volt DC system shows low voltage, the most likely cause is

How can the direction of rotation of a DC electric motor be changed?

Static inverters are electronic devices that change DC to AC with the

Aircraft which operate only AC generators (alternators) as a primary source of electrical power normally provide current suitable for battery charging through the use of

During inspection of an anti-collision light installation for condition and proper operation, it should be determined that

Major adjustments on equipment such as regulators, contactors, and inverters are best accomplished outside the airplane on test benches with necessary instruments and equipment. Adjustment procedure should be as outlined by

A battery-generator system provides direct current. On installations requiring alternating current from the battery-generator system, it is necessary to have

An aircraft electrical circuit control relay is

The purpose of a rectifier in an electrical system is to change

What is the ratio of turns between the primary coil winding and the secondary coil winding of a transformer designed to triple its input voltage?

In an AC circuit with no phase lead or lag, which is true?

How are generators rated?

How is a shunt-wound DC generator connected?

The poles of a generator are laminated to

What is the frequency of an alternator dependent upon?

Where is the generator rating and performance data located?

Residual voltage is a result of magnetism in the

In troubleshooting an electrical circuit, if an ohmmeter is properly connected across a circuit component and some value of resistance is read,

CSD generators are usually cooled by

A CSD unit drives a generator through the use of

Integrated drive generators (IDG) employ a type of high output AC generator that utilizes

If the Integrated Drive Generator (IDG) scavenge oil filter is contaminated with metal, you should

When necessary during operation, CSD disconnect is usually accomplished by

A CSD unit that is disconnected in flight, due to a malfunction such as overtemperature, may be reconnected