ENGINE ELECTRICAL PART 1

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

Aircraft wire size is determined by using a(n). ohmmeter. wire gauge. dial caliper.

Which Federal Aviation Regulation requirement prevents the use of automatic reset circuit breakers?. 14 CFR Part 21. 14 CFR Part 23. 14 CFR Part 91.

When a 28-volt, 75-ampere generator is installed on an aircraft, an electrical load analysis ground check is performed and it is determined that the battery is furnishing 57 amperes to the system, with all electrical equipment operating. This indicates. the load exceeds the maximum system percentage capacity. that the generator load will exceed the generator limit. the load will be within the generator load limit.

When selecting an electrical switch for installation in an aircraft circuit utilizing a direct current motor,. a switch designed for DC should be chosen. a derating factor should be applied. only switches with screw-type terminal connections should be used.

How are the rotor windings of an aircraft alternator usually excited?. By a constant ac voltage from the battery. By a constant ac voltage. By a variable direct current.

When the starter switch to the aircraft gas turbine engine starter-generator is energized and the engine fails to rotate, one of the probable causes would be the. power lever switch is defective. undercurrent solenoid contacts are defective. starter solenoid is defective.

What is a basic advantage of using AC for electrical power for a large aircraft?. 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 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 more current and can use smaller and lighter weight wiring.

What is used to polish commutators or slip rings?. Double-0 sandpaper. Stiff bristle brushes. Emery cloths.

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

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

A certain direct current series motor mounted within an aircraft draws more amperes during start than when it is running under its rated load. The most logical conclusion that may be drawn is. the starting winding is shorted. the brushes are floating at operating RPM because of weak brush springs. the condition is normal for this type of motor.

One way that the automatic ignition relight systems are activated on gas turbine engines is by a. drop in compressor discharge pressure. sensing switch located in the tailpipe. drop in fuel flow.

Bonding jumpers should be designed and installed in such a manner that they. are not subjected to flexing by relative motion of airframe or engine components. provide a low electrical resistance in the ground circuit. prevent buildup of a static electrical charge between the airframe and the surrounding atmosphere.

The time/current capacities of a circuit breaker or fuse must be. above those of the associated conductor. equal to those of the associated conductor. below those of the associated conductor.

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

The generating system of an aircraft charges the battery by using. constant current and varying voltage. constant voltage and varying current. constant voltage and constant current.

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

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

When does current flow through the coil of a solenoid-operated electrical switch?. Continually, as long as the aircraft's electrical system master switch is on. Continually, as long as the control circuit is complete. Only until the movable points contact the stationary points.

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 decrease. Generator output voltage will not be affected. Generator output voltage will increase.

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

A typical barrier type aircraft terminal strip is made of. paper-base phenolic compound. polyester resin and graphite compound. layered aluminum impregnated with compound.

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

A term commonly used when two or more electrical terminals are installed on a single lug of a terminal strip is. strapping. piggy backing.. stacking.

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

What is the smallest terminal stud allowed for aircraft electrical power systems?. No. 6. No. 8. No. 10.

Which Federal Aviation Regulation specifies that each resettable circuit protective device requires a manual operation to restore service after the device has interrupted the circuit?. 14 CFR Part 23. 14 CFR Part 43. 14 CFR Part 91.

What precaution is usually taken to prevent electrolyte from freezing in a lead-acid battery?. Place the aircraft in a hangar. Remove the battery and keep it under constant charge. Keep the battery fully charged.

Starter brushes should be replaced when they are worn down to. one-half of the original length. three-quarters of the original length. one-quarter of the original length.

In order to reduce the possibility of ground shorting the circuits when the connectors are separated for maintenance, the AN and MS electrical connectors should be installed with the. socket section on the ground side of the electrical circuit. pin section on the ground side of the electrical circuit. pin section on the positive side of the electrical circuit.

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

(Refer to Figure 4.) The following data concerning the installation of an electrical unit is known: current requirements for continuous operation -- 11 amperes; measured cable length -- 45 feet; system voltage -- 28 volts (do not exceed 1 volt drop); cable in conduit and bundles. What is the minimum size copper electrical cable that may be selected?. No. 10. No. 12. No. 14.

The constant current method of charging a nickel-cadmium battery. will bring it up to fully charged in the shortest amount of time. will lead to cell imbalance over a period of time. is the method most effective in maintaining cell balance.

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