Z-59 (Electrical Engineering) WRITTEN EXAM TEST
QUESTION AND ANSWERS RATED A.
(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, - ✔✔ANSW✔✔..both No. 1 and
No. 2 are true.
(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? - ✔✔ANSW✔✔..No. 12.
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 -
✔✔ANSW✔✔..the condition is normal for this type of motor.
A high surge of current is required when a dc electric motor is first
started. As the speed of the motor increases, - ✔✔ANSW✔✔..the
counter emf builds up and opposes the applied emf, thus reducing
the current flow through the armature.
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 - ✔✔ANSW✔✔..is into the negative terminal and out
the positive terminal.
, Aircraft that operate more than one generator connected to a
common electrical system must be provided with -
✔✔ANSW✔✔..individual generator switches that can be operated
from the cockpit during flight.
Alternators (ac generators) that are driven by a constant-speed
drive (CSD) mechanism are used to regulate the alternator to a
constant - ✔✔ANSW✔✔..hertz output.
As the flux density in the field of a dc generator increases and the
current flow to the system increases, the - ✔✔ANSW✔✔..force
required to turn the generator increases.
As the generator load is increased (within its rated capacity), the
voltage will - ✔✔ANSW✔✔..remain constant and the amperage
output will increase.
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? - ✔✔ANSW✔✔..Series.
Generator voltage will not build up when the field is flashed and
solder is found on the brush cover plate. These are most likely
indications of - ✔✔ANSW✔✔..an open armature.
How are the rotor windings of an aircraft alternator usually
excited? - ✔✔ANSW✔✔..By a variable direct current.
How many hours will a 140 ampere-hour battery deliver 15
amperes? - ✔✔ANSW✔✔..9.33 hours.
QUESTION AND ANSWERS RATED A.
(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, - ✔✔ANSW✔✔..both No. 1 and
No. 2 are true.
(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? - ✔✔ANSW✔✔..No. 12.
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 -
✔✔ANSW✔✔..the condition is normal for this type of motor.
A high surge of current is required when a dc electric motor is first
started. As the speed of the motor increases, - ✔✔ANSW✔✔..the
counter emf builds up and opposes the applied emf, thus reducing
the current flow through the armature.
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 - ✔✔ANSW✔✔..is into the negative terminal and out
the positive terminal.
, Aircraft that operate more than one generator connected to a
common electrical system must be provided with -
✔✔ANSW✔✔..individual generator switches that can be operated
from the cockpit during flight.
Alternators (ac generators) that are driven by a constant-speed
drive (CSD) mechanism are used to regulate the alternator to a
constant - ✔✔ANSW✔✔..hertz output.
As the flux density in the field of a dc generator increases and the
current flow to the system increases, the - ✔✔ANSW✔✔..force
required to turn the generator increases.
As the generator load is increased (within its rated capacity), the
voltage will - ✔✔ANSW✔✔..remain constant and the amperage
output will increase.
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? - ✔✔ANSW✔✔..Series.
Generator voltage will not build up when the field is flashed and
solder is found on the brush cover plate. These are most likely
indications of - ✔✔ANSW✔✔..an open armature.
How are the rotor windings of an aircraft alternator usually
excited? - ✔✔ANSW✔✔..By a variable direct current.
How many hours will a 140 ampere-hour battery deliver 15
amperes? - ✔✔ANSW✔✔..9.33 hours.
