Sistemas Eléctricos

If one switch is used to control all navigation lights, the lights are most likely connected. parallel to each other and in series with the switch. in series with each other and parallel to the switch. in series with each other and in series with the switch.

If a wire is installed so that it comes in contact with some moving parts, what protection should be given the wire?. Pass through conduit. Wrap with soft wire solder into a shield. Wrap with friction tape.

How many hours will a 140 ampere-hour battery deliver 15 amperes?. 1.40 hours. 9.33 hours. 14.0 hours.

What speed must an eight-pole AC generator turn to produce 400-Hertz ac?. 6,000 RPM. 400 RPM. 1,200 RPM.

How can the state-of-charge of a nickel-cadmium battery be determined?. By measuring the specific gravity of the electrolyte. By a measured discharge. By the level of the electrolyte.

Electric circuits are protected from overheating by means of. shunts. thermocouples. fuses.

Which of the following should be accomplished in the installation of aircraft wiring?. Provide adequate slack in the wire bundle to compensate for large changes in temperature. Support the bundle to structure and/ or solid fluid lines to prevent chafing damage. Locate the bundle above flammable fluid lines and securely clamp to structure.

If it is necessary to use an electrical connector where it may be exposed to moisture, the mechanic should. coat the connector with grease. use a special moisture-proof type. spray the connector with varnish or zinc-chromate.

What is the advantage of a current limiter?. It can be reset easily. It will take overload for a short period. It breaks circuit quickly.

(Refer to Figure 18.) Which of the batteries are connected together incorrectly?. 2. 1. 3.

If the points in a vibrator-type voltage regulator stick in the closed position while the generator is operating, what will be the probable result?. Generator output voltage will increase. Generator output voltage will not be affected. Generator output voltage will decrease.

In aircraft electrical systems, automatic reset circuit breakers. should not be used as circuit protective devices. must be used in all circuits essential to safe operation of the aircraft. are useful where only temporary overloads are normally encountered.

The circuit breaker in the instrument lighting system protects the. wiring from too much voltage. wiring from too much current. lights from too much current.

Why is a constant-speed drive used to control the speed of some aircraft engine-driven generators?. To eliminate uncontrolled surges of current to the electrical system. So that the frequency of the alternating current output will remain constant. So that the voltage output of the generator will remain within limits.

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. correctly. backwards. low voltage.

When installing electrical wiring parallel to a fuel line, the wiring should be. in metal conduit. above the fuel line. in a non-conductive fire-resistant sleeve.

How are generators rated?. The impedance at rated voltage. Watts at rated voltage. Amperes at rated voltage.

A certain switch is described as a single-pole, double-throw switch (SPDT). The throw of a switch indicates the number of. circuits each pole can complete through the switch. terminals at which current can enter or leave the switch. places at which the operating device (toggle, plunger, etc.) will come to rest and at the same time open or close a circuit.

The purpose of a rectifier in an electrical system is to change. the frequency of alternating current. alternating current to direct current. direct current to alternating current.

The purpose of providing a space underneath the plates in a lead acid battery's cell container is to. prevent sediment buildup from contacting the plates and causing a short circuit. ensure that the electrolyte quantity ratio to the number of plates and plate area is adequate. allow for convection flow of the electrolyte in order to provide for cooling of the plates.

When considering an alteration, the criteria upon which the selection of electric cable size should be based are. current-carrying capacity and applied voltage. applied voltage and allowable voltage drop. current-carrying capacity and allowable voltage drop.

Aircraft fuse capacity is rated in. amperes. ohms. volts.

What is normally used to bond noncontinuous stainless steel aircraft components?. Aluminum jumpers. Stainless steel jumpers. Copper jumpers.

Which of the following copper electrical cable sizes should be selected to replace a No. 6 aluminum electrical cable?. No. 4. No. 8. No. 6.

Which of the following best describes the contributing factors to thermal runaway in a nickel-cadmium battery installed in an aircraft?. High internal resistance intensified by high cell temperatures and a high current discharge/charge rate in a constant potential charging system. Low internal resistance intensified by high cell temperatures and a high current discharge/charge rate in a constant potential charging system. Low internal resistance intensified by high cell temperatures and a high voltage discharge/charge rate in a constant current charging system.

The three kinds of circuit-protection devices used most commonly in aircraft circuits are. circuit breakers, fuses, and current limiters. circuit breakers, resistors, and current limiters. circuit breakers, capacitors, and current limiter plug-ins mechanical reset types.

The electrolyte of a nickel cadmium battery is highest when the battery is. in a fully charged condition. in a discharged condition. under a no-load condition.

One advantage of using ac electrical power in aircraft is. that the effective voltage is 1.41 times the maximum instantaneous voltage; therefore, less power input is required. that ac electrical motors can be reversed while dc motors cannot. greater ease in stepping the voltage up or down.

The end-of-charge voltage of a 19-cell nickel-cadmium battery, measured while still on charge,. must be 1.2 to 1.3 volts per cell. depends upon its temperature and the method used for charging. must be 1.4 volts per cell.

(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?. Short in the up limit switch. Short in the down limit switch. Short in the gear safety switch.

What determines the amount of current which will flow through a battery while it is being charged by a constant voltage source?. The state-of-charge of the battery. The total plate area of the battery. The ampere-hour capacity of the battery.

An aircraft electrical circuit control relay is. an electronically operated switch. a device which converts electrical energy to kinetic energy. any conductor which receives electrical energy and passes it on with little or no resistance.

What may result if water is added to a nickel-cadmium battery when it is not fully charged?. Excessive spewing is likely to occur during the charging cycle. No adverse effects since water may be added anytime. Excessive electrolyte dilution.

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

The part of a dc alternator power system that prevents reverse flow of current from the battery to the alternator is the. voltage regulator. rectifier. reverse current relay.

Bonding connections should be tested for. amperage value. reactance. resistance value.

Which statement regarding the hydrometer reading of a lead-acid storage battery electrolyte is true?. A specific gravity correction should be added to the hydrometer reading if the electrolyte temperature is below 59__degrees__F. The hydrometer reading will give a true indication of the capacity of the battery regardless of the electrolyte temperature. The hydrometer reading does not require a temperature correction if the electrolyte temperature is 80__degrees__F.

As the generator load is increased (within its rated capacity), the voltage will. decrease and the amperage output will increase. remain constant and the amperage output will increase. remain constant and the amperage output will decrease.

Alternators (ac generators) that are driven by a constant-speed drive (CSD) mechanism are used to regulate the alternator to a constant. amperage output. hertz output. voltage output.

How should a voltmeter be connected?. In series with the load. In series with the source. In parallel with the load.

The voltage in an ac transformer secondary that contains twice as many loops as the primary will be. greater and the amperage greater than in the primary. less and the amperage greater than in the primary. greater and the amperage less than in the primary.

Oil canning of the sides of aluminum or steel electrical junction boxes is considered to be. a shorting hazard. acceptable operation. normal operation in vibration prone areas.

If a generator is malfunctioning, its voltage can be reduced to residual by actuating the. rheostat. generator master switch. master solenoid.

(Refer to Figure 20.) What is the minimum circumstance that will cause the landing gear warning horn to indicate an unsafe condition?. Any gear not down and locked, and one throttle retarded. Any gear up and both throttles retarded. All gears up and one throttle retarded.

ON-OFF two position engine electrical switches should be installed. so the ON position is reached by a forward or upward motion. so that the toggle will move in the same direction as the desired motion of the unit controlled. under a guard.

Aircraft that operate more than one generator connected to a common electrical system must be provided with. an automatic device that will isolate nonessential loads from the system if one of the generators fails. automatic generator switches that operate to isolate any generator whose output is less than 80 percent of its share of the load. individual generator switches that can be operated from the cockpit during flight.

(Refer to Figure 19). Which repair should be made if the gear switch was placed in UP position and the gear does not retract?. Replace electrical wire No. 15. Replace the down limit switch. Replace electrical wire No. 12.

In nickel-cadmium batteries, a rise in cell temperature. causes a decrease in internal resistance. causes an increase in internal resistance. increases cell voltage.

What is used to polish commutators or slip rings?. Crocus cloth or fine oilstone. Aluminum oxide or garnet paper. Very fine sandpaper.

What is a basic advantage of using ac for electrical power for a large aircraft?. AC systems operate at lower voltage than dc systems and therefore use less current and can use smaller and lighter weight wiring. AC systems operate at higher voltage than dc systems and therefore use less current and can use smaller and lighter weight wiring. AC systems operate at higher voltage than dc systems and therefore use more current and can use smaller and lighter weight wiring.

As the flux density in the field of a dc generator increases and the current flow to the system increases, the. force required to turn the generator increases. generator voltage decreases. generator amperage decreases.

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. combined resistance and current-carrying capacity. cross-sectional area. current-carrying capacity.

(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?. Short in the gear safety switch. Short in the up limit switch. Short in the down limit switch.

Which of the following factors must be taken into consideration when determining the wire size to use for an aircraft installation? 1. Mechanical strength. 2. Allowable power loss. 3. Ease of installation. 4. Resistance of current return path through the aircraft structure. 5. Permissible voltage drop. 6. Current carrying capability of the conductor. 7. Type of load (continuous or intermittent). 2, 5, 6, 7. 2, 4, 6, 7. 1, 2, 4, 5.

The primary considerations when selecting electric cable size are. the voltage and amperage of the load it must carry. the system voltage and cable length. current-carrying capacity and allowable voltage drop.

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

A high surge of current is required when a dc electric motor is first started. As the speed of the motor increases,. the counter emf builds up and opposes the applied emf, thus reducing the current flow through the armature. the counter emf decreases proportionally. the applied emf increases proportionally.

When adding a rheostat to a light circuit to control the light intensity, it should be connected in. parallel with the light. series with the light. series parallel with the light switch.

The most effective method of regulating aircraft direct current generator output is to vary, according to the load requirements, the. generator speed. strength of the stationary field. number of rotating armature loops in use.

What are two types of ac motors that are used to produce a relatively high torque?. Three-phase induction and capacitor start. Shaded pole and shunt field. Shunt field and single phase.

The electrolyte of a nickel-cadmium battery is the lowest when the battery is. under a heavy load condition. being charged. in a discharged condition.

Aluminum wire must be stripped very carefully because. stripping nicks can cause short circuits. high resistance will develop in stripping nicks. individual strands will break easily after being nicked.

Which statement relating to electric wiring is true?. When attaching a terminal to the end of an electric cable, it should be determined that the strength of the cable-to-terminal joint is at least equal to the tensile strength of the cable itself. All electric cable splices should be covered with soft insulating tubing (spaghetti) for mechanical protection against external abrasion. When attaching a terminal to the end of an electric cable, it should be determined that the strength of the cable-to-terminal joint is at least twice the tensile strength of the cable.

Electric motors are often classified according to the method of connecting the field coils and armature. Aircraft engine starter motors are generally of which type?. Series. Shunt (parallel). Compound.

Which of the following statements is/are generally true regarding the charging of several aircraft batteries together? 1. Batteries of different voltages (but similar capacities) can be connected in series with each other across the charger, and charged using the constant current method. 2. Batteries of different ampere-hour capacity and same voltage can be connected in parallel with each other across the charger, and charged using the constant voltage method. 3. Batteries of the same voltage and same ampere-hour capacity must be connected in series with each other across the charger, and charged using the constant current method. 1 and 2. 3. 2 and 3.

Where electric cables must pass through holes in bulkheads, formers, ribs, firewalls, etc., the wires should be protected from chafing by. wrapping with electrical tape. using a suitable grommet. wrapping with plastic.

Nickel-cadmium batteries which are stored for a long period of time will show a low liquid level because. electrolyte becomes absorbed into the plates. electrolyte evaporates through the vents. of current leakage from individual cells.

What is the advantage of a circuit breaker when compared to a fuse?. Resettable and reusable. Always eliminates the need of a switch. Never needs replacing.

The presence of any small amount of potassium carbonate deposits on the top of nickel-cadmium battery cells in service is an indication of. plate sulfation. excessive gassing. normal operation.

Which of the following is regulated in a generator to control its voltage output?. The strength of the field. Speed of the armature. Number of windings in the armature.

A lead-acid battery with 12 cells connected in series (no-load voltage = 2.1 volts per cell) furnishes 10 amperes to a load of 2-ohms resistance. The internal resistance of the battery in this instance is. 0.52 ohm. 5.0 ohms. 2.52 ohms.

What is the purpose of a reverse-current cut out relay?. It opens the main generator circuit whenever the generator voltage drops below the battery voltage. It prevents fluctuations of generator voltage. It eliminates the possibility of reversed polarity of the generator output current.

A circuit breaker is installed in an aircraft electrical system primarily to protect the. circuit and should be located as close to the unit as possible. electrical unit in the circuit and should be located as close to the source as possible. circuit and should be located as close to the source as possible.

Circuits that must be operated only in an emergency or whose inadvertent activation could endanger a system frequently employ. spring-loaded to off toggle or rocker switches. guarded switches. push-pull-type circuit breakers only (no switches).

(Refer to Figure 19.) What is the indication of the red landing gear position light under the following conditions? Aircraft on jacks. Landing gear in transit. Warning horn sounding. flashing. extinguished. illuminated.

The maximum number of terminals that may be connected to any one terminal stud in an aircraft electrical system is. three. two. four.

How does the routing of coaxial cables differ from the routing of electrical wiring?. Coaxial cables are routed at right angles to stringers or ribs. Coaxial cables are routed parallel with stringers or ribs. Coaxial cables are routed as directly as possible.

What is the likely result of servicing and charging nickel-cadmium and lead acid batteries together in the same service area?. Lowered amp-hour capacities, for both types of batteries. Contamination of both types of batteries. Reduced battery service life for both types of batteries.

Electrical switches are rated according to the. resistance rating of the switch and the wiring. resistance and the temperature rating. voltage and the current they can control.

What is the minimum bend radius for an electrical wire bundle?. Ten times the outside diameter of the bundle. Fifteen times the outside diameter of the bundle. Five times the outside diameter of the bundle.

How should the splices be arranged if several are to be located in an electrical wire bundle?. Grouped together to facilitate inspection. Enclosed in a conduit. Staggered along the length of the bundle.

If electrolyte from a lead-acid battery is spilled in the battery compartment, which procedure should be followed?. Apply boric acid solution to the affected area followed by a water rinse. Apply sodium bicarbonate solution to the affected area followed by a water rinse. Rinse the affected area thoroughly with clean water.

A fully charged lead-acid battery will not freeze until extremely low temperatures are reached because. most of the acid is in the solution. the acid is in the plates, thereby increasing the specific gravity of the solution. increased internal resistance generates sufficient heat to prevent freezing.

During inspection of the terminal strips of an aircraft electrical system, it should be determined that. the terminal studs are anchored against rotation. only plain nuts and lockwashers have been used for terminal attachment to the studs. only locknuts have been used for terminal attachment to the studs.

Which condition is an indication of improperly torqued cell link connections of a nickel-cadmium battery?. Toxic and corrosive deposits of potassium carbonate crystals. Light spewing at the cell caps. Heat or burn marks on the hardware.

(Refer to Figure 20.) What will illuminate the amber indicator light?. Retarding one throttle and closing the left wheel gear locked down switch. Closing the nose, left and right wheel gear full retract switches. Closing the nosewheel gear full retract switch.

Arcing at the brushes and burning of the commutator of a motor may be caused by. low mica. weak brush springs. excessive brush spring tension.

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. applying a light coat of dielectric grease. dusting the cable with powdered graphite. dusting the cable with powdered soapstone.

According to the electron theory of the flow of electricity, when a properly functioning dc alternator and voltage regulating system is charging an aircraft's battery, the direction of current flow through the battery. is into the negative terminal and out the positive terminal. cycles back and forth with the number of cycles per second being controlled by the rotational speed of the alternator. is into the positive terminal and out the negative terminal.

AN/MS electrical connectors are specifically designed to meet. military specifications. International Civil Aviation Organization (ICAO) standards. Technical Standard Order (TSO) specifications.

(1) Alternators are rated in volt-amps, which is a measure of the apparent power being produced by the generator. (2) Alternating current has the advantage over direct current in that its voltage and current can easily be stepped up or down. Regarding the above statements,. only No. 1 is true. both No. 1 and No. 2 are true. only No. 2 is true.

The pin section of an AN/MS connector is normally installed on. the ground side of a circuit. either side of a circuit (makes no difference). the power supply side of a circuit.

Grounding is electrically connecting a conductive object to the primary structure. One purpose of grounding is to. prevent current return paths. allow static charge accumulation. prevent development of radio frequency potentials.

What is the frequency of most aircraft alternating current?. 115 Hertz. 400 Hertz. 60 Hertz.

When a charging current is applied to a nickel cadmium battery, the cells emit gas. throughout the charging cycle. toward the end of the charging cycle. especially if the electrolyte level is high.

What protection to wires and cables does conduit provide when used in aircraft installations?. Electromagnetic. Structural. Mechanical.

As a general rule, starter brushes are replaced when they are approximately. two-thirds their original length. one-third their original length. one-half their original length.

When selecting hardware for attaching bonding connections to an aircraft structure, which of the following should be considered? 1. Mechanical strength. 2. Allowable power loss. 3. Ease of installation 4. Permissible voltage drop. 5. Amount of current to be carried. 6. Type of load (continuous or intermittent). 1, 3, 5. 4, 5, 6. 1, 2, 3.

What type of electric motor is generally used with a direct-cranking engine starter?. Direct current, series-wound motor. Direct current, shunt-wound motor. Synchronous motor.

The voltage output of an alternator may be regulated by controlling the. speed of the alternator. resistance in the rotor windings. voltage output of the dc exciter.

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. single-pole, double-throw (SPDT), two-position switch. double-pole, single-throw (DPST), two-position switch. single-pole, single-throw (SPST), two-position switch.

The method used to rapidly charge a nickel-cadmium battery utilizes. constant current and constant voltage. constant current and varying voltage. constant voltage and varying current.

Electric wire terminals for most aircraft applications must be what type?. Slotted. Hook. Ring.

Upon what does the output frequency of an ac generator (alternator) depend?. The speed of rotation, the strength of the field, and the number of field poles. The speed of rotation and the strength of the field. The speed of rotation and the number of field poles.

A circuit protection device called a current limiter is essentially a slow-blow fuse and is designed to be used in. 400 cycle AC circuits. starter-generator circuits. heavy power circuits.

What kind of switch should you install in a single wire circuit that required the switch to be manually held in the ON position?. Single-pole, single-throw (SPST), two-position normally open (NO). Single-pole, single-throw (SPST), single-position. Single-pole, double-throw (SPDT), single-position normally open (NO).

What is an important factor in selecting aircraft fuses?. The current exceeds a predetermined value. The voltage rating should be lower than the maximum circuit voltage. Capacity matches the needs of the circuit.