ELEC 02

1. Armature windings are contained in the stator. An electromagnetic field is produced by a 6-pole rotor. This is a description of: A) A 3-phase AC generator. B) A frequency wild DC generator. C) A 3-phase DC generator. D) A single phase AC busbar.

2. Which of the following is/are true of a 3-phase AC generator:1- A 4-pole rotor produces the current.2- A 2-pole rotor produces the current.3- A 6-pole rotor produces the current.4- The phase separation is 120º.5- The phase separation is 180º.6- The phase separation is 90º.7- The output frequency decreases with increasing RPM of the generator. 8- The output frequency increases with increasing RPM of the generator. A) 3 4 8 B) 1 2 3 C) 2 4 6 D) 1 3 4

3. A CSD is a: A) Constant speed drive. B) Constant source device. C) Constant speed device. D) Control speed drive.

4. Which of the following parameters is/are monitored by the CSD:1- Engine RPM.2- Frequency.3- Phase.4- Voltage. A) 2 3 B) 1 3 C) 1 2 D) 1 4

5. The single unit combining the generator and the constant speed drive is known as: A) An integrated drive generator. B) A DC starter-generator. C) A voltage control unit. D) A ‘frequency wild’ generator.

6. Which of the following accurately describes the function or operation of the CSD disconnect system? A) Once operated, the CSD cannot be reconnected in flight B) Once operated, the associated generator continues to be driven but there is no electrical output to the busbar(s). C) The disconnect unit disconnects the auxiliary gearbox from the engine. D) The disconnect unit monitors the output frequency and disconnects the generator from the busbar if it is outside the acceptable limits.

7. High oil temperature and/or excessively low oil pressure in a CSD could lead to: A) Mechanical failure of the CSD, which interferes with the free running of the gas turbine engine. B) Mechanical failure of the engine caused by a seized CSD. C) Loss of oil pressure to the engine's main bearings. D) AC of the incorrect frequency being supplied to a common busbar.

8. In a three-phase AC generator, the excitation current is delivered to the rotor by routing it either through carbon brushes which are in contact with slip rings, or by electromagnetic __________. A) induction B) force C) impedance D) frequency

9. A ‘frequency wild’ generator produces __________ current whose frequency varies depending on the __________ of the engine. A) AC; RPM B) DC; RPM C) AC; number of stators D) DC; number of stators

10. The CSD is a hydromechanical system serviced by its own supply of __________. A) oil B) electricity

11. The sources of mechanical power for an AC generator include:1- A main engine.2- A constant speed drive.3- An auxiliary power unit (APU).4- A ram air turbine (RAT)5- A ‘frequency wild’ generator.6- An hydraulic pump. A) 1 3 4 6 B) 1 2 3 4 C) 2 3 4 5 D) 4 5 6

12. When ground power is accepted, other sources of power are __________. A) isolated automatically B) isolated manually C) paralleled with the external power supply

13. Which of the following are the possible purposes of a transformer?1- To step- down an AC voltage.2- To ensure constant frequency AC.3- To step-up an AC voltage.4- To step-down or step-up a DC voltage. A) 1 3 B) 2 3 C) 1 4 D) 1 2

14. The unit used to step down AC and convert it to DC is: A) A transformer rectifier unit. B) A static inverter. C) A constant speed drive. D) A voltage control unit.

15. A TRU: A) Steps-down AC and then converts it to DC. B) Converts AC to DC and then steps it down. C) Simultaneously steps-down and converts AC to DC. D) Can convert AC to DC or vice-versa.

16. A transformer rectifier unit (TRU) usually __________ __________ and converts it to __________. A) steps down AC; DC B) steps down DC; AC C) steps up AC; DC D) steps up DC; AC

17. A static inverter transforms __________ to __________. A) DC; AC B) AC; DC

18. In a single-engine aircraft, with a DC electrical system, which of the following can supply power to the main busbar?1- An APU.2- The aircraft's battery.3- An inverter.4- A DC alternator or generator.5- An AC alternator.6- An external battery. A) 2 4 6 B) 1 2 3 C) 1 3 5 D) 2 4 5

19. When loads are connected to the main busbar in parallel, they can be individually protected by which of the following: 1- Fuses.2- Split busbars.3- Battery contactors/isolators.4- Voltage control unit.5- Circuit breakers. A) 1 5 B) 1 3 C) 2 4 D) 2 5

20. The single-engine aircraft's distribution system is monitored using which of the following: 1- A voltmeter.2- A battery capacity meter.3- A frequency meter. 4- An ammeter. A) 1 4 B) 2 4 C) 2 3 D) 1 3

21. A single-engine aircraft’s distribution system is usually __________. A) DC B) AC

22. A small twin-engine aircraft primarily has a __________ distribution system. A) DC B) AC

23. A small twin-engine aircraft uses one or more __________ to provide __________ power to those systems which require it. A) inverters; AC B) inverters; DC C) transformers; DC D) transformers; AC

24. In a single-engine aircraft electrical system, the majority of loads are connected to the main busbar in __________. A) parallel B) series

25. In a single-engine aircraft after engine start when the generator/alternator output __________ the voltage of the battery, a generator cut-out closes, to connect the generator/alternator to the main busbar. A) exceeds B) equals

26. In a single-engine aircraft, if the engine fails, or the generator fails in flight, the only source of electrical power will be the __________. A) battery B) inverter

27. In a single-engine aircraft's distribution system, a zero-centre ammeter shows negative amps, and/or a generator warning light illuminates, if the generator voltage __________ the battery voltage. A) falls below B) exceeds C) falls below or exceeds

28. A small twin-engine aircraft usually has __________ generator(s) per engine.

29. In a small twin-engine aircraft, the generators __________. A) are paralleled onto a main busbar B) supply individual generator busbars

30. In a small twin-engine aircraft, an __________ circuit matches the voltage outputs of the generators. A) equalising B) regulating

31. In a small twin-engine aircraft, the output capacity of one generator or alternator __________ be sufficient to maintain all the electrical loads in the event of a single generator failure. A) may or may not B) will never

32. In a small twin-engine aircraft, a short-circuit on the main busbar __________ be overcome by supplying it with electrical power from a different source. A) cannot B) can

33. With reduced power available (e.g. after a generator failure) it is usually advisable or required to switch-off some of the more demanding loads such as the galley ovens and passenger entertainment system. This is a description of: A) Load shedding. B) Load sharing. C) Overloading. D) Frequency sharing.

34. Which of the following are typical AC loads in a commercial jet transport aircraft?1- The FMGC.2- The VHF radios.3- The air conditioning pack control. 4- The flight deck display units (DUs).5- The primary flight controls' trimmer motors. A) 3 4 B) 1 5 C) 3 4 D) 2 4

35. Which of the following are typical DC loads on a commercial jet transport aircraft?1- The FMGC.2- The VHF radios.3- The air conditioning pack control. 4- The flight deck display units.5- The primary flight controls' trimmers. A) 1 2 5 B) 1 3 5 C) 2 3 4 D) 1 2 3

36. The device which monitors and controls generator output and protects the system from abnormal generator outputs by isolating it from its busbar is the: A) Generator control unit. B) Generator isolation switch. C) CSD disconnect system. D) Differential fault protection system.

37. A __________ busbar system has a common busbar fed by all AC generators. A) parallel B) series

38. A parallel busbar system has a bus tie which is normally __________ to link all the generators. A) closed B) open

39. When linked to a common busbar, the generators __________ the load. A) share B) distribute C) assign

40. A paralleled system must use generators which output at the same frequency, phase and phase __________. A) angle B) frequency

41. A __________ busbar system has separate AC busbars for each AC generator. A) split B) separated C) joined

42. A split busbar system has a bus tie which __________ when one side of the system is unpowered. A) closes B) opens

43. A split busbar system can use frequency wild generators but, in practice, the output frequency is normally kept very close to __________ Hz.

44. On split and parallel busbar systems, power is usually provided by generators driven by the __________. A) main engines B) APU C) battery

45. On split and parallel busbar systems external __________ can be provided to the main busbars on the ground before engine start. A) AC B) DC

46. External AC __________ the output provided by a main engine AC generator. A) is automatically isolated from B) can be paralleled with

47. AC power __________ provided by the APU in flight when one generator fails. A) can be B) can never be

48. On a twin-engined commercial jet transport aircraft, each main generator __________ usually sufficiently powerful to power the entire electrical system. A) is B) is not

49. On a twin-engined commercial jet transport aircraft, the APU generator__________ normally sufficiently powerful to power the entire electrical system. A) is B) is not

50. When a generator fails it’s__________ possible to power the failed side with the APU generator. A) usually B) never C) rarely

51. The __________ servicing busbar allows engineers to power some electrical loads (e.g. cabin lights and cargo hatch operation) without powering up the entire electrical system. A) ground B) APU

52. The __________ busbar is permanently connected to its associated battery. A) hot B) batt

53. The __________ busbars maintain a source of AC to essential AC loads when other sources of AC have failed. A) essential AC B) DC inverter

54. The __________ busbars supply the essential DC loads when one or more TRUs have failed. A) essential DC B) battery

55. The __________ busbar provides limited capacity DC to power the most essential DC loads (such as fire extinguishers). A) BAT B) Essential TR

56. On a split busbar system, used by a twin-engine commercial jet transport aircraft, the failure of a single main generator can usually be entirely compensated for by __________ the bus tie or by bringing the gas turbine powered APU generator on line. A) closing B) opening

57. On a large commercial jet transport aircraft, DC is supplied via __________ from various AC busbars. A) TRUs B) converter C) inverter

58. When all other sources of AC generation have failed, emergency AC can be provided from the DC system via an __________. A) inverter B) TRUs C) converter

59. The electrical power produced by an operational generator will cease to be supplied to a main busbar if the __________ switch is opened. A) isolator B) IDG

60. A generator __________ switch de-powers its generator by electrically isolating the generator field by opening the exciter contactor. A) control B) IDG C) circuit breaker

61. On a split bus system, when it is set to __________, the bus tie automatically closes upon failure of 1 main generator . A) AUTO B) ON C) OFF

62. On a split bus system, if the bus tie switch is set to __________, failure of 1 generator means the bus tie remains open. A) OFF B) ON C) AUTO

63. Battery temperature must be monitored to ensure than no battery becomes excessively __________. A) hot B) cold

64. Battery temperature monitoring is especially important for __________ batteries. A) NiCd and LiB B) lead-acid

65. The system that automatically isolates a busbar if a short-circuit is sensed in that busbar is known as: A) Differential fault protection. B) Generator isolation. C) Load shedding. D) Load sharing.

66. The purpose of an electric motor is to convert: A) Electrical energy into mechanical energy. B) Mechanical energy into electrical energy. C) Potential energy into mechanical energy. D) Electrical energy into potential energy.

67. The amount of torque produced by an electric motor depends on which of the following:1- The current. 2- The commutator.3- The phase shift.4- The voltage. A) 1 4 B) 1 3 C) 3 4 D) 2 4

68. Because they are similar is design, a generator and electrical motor may be combined into a single __________. A) starter-generator unit B) starter motor unit C) integrated drive generator (IDG)

69. The size of the engine determines the required size of the starter motor because a very large unit requires more __________ to turn it at sufficient RPM during engine start. A) torque B) power C) thrust

70. Small gas turbine engines, such as the APU, can usually be started with an electric motor powered by the _______. A) battery B) AC generator C) APUS

71. Large turbine engines __________ be started from the aircraft's batteries. A) cannot B) can

72. For engine starting, large turbine engines require either external power or internal power from the __________ or another main engine. A) APU B) battery

73. A rotor _____ will result in excessive current and risk of damage or electrical fire. A) seizure B) runaway

74. A rotor __________ may result in physical damage to the motor. A) runaway B) seizure

75. The rotating part of the electric motor is called the __________. A) rotor B) armature C) slip ring

76. The stationary part of the electric motor is called the __________. A) stator B) brushes C) commutator

77. Electrical motors __________ be AC or DC powered. A) can B) can not

78. Which of the following effects can be caused by high temperature in a semiconductor:1- Increased lifespan.2- Reduced lifespan.3- Complete failure. 4- Switching errors. 5- Logic errors. A) 2 3 4 5 B) 1 2 3 C) 3 4 5 D) 2 3 4

79. All inputs to be high (logic1) to get a high output (logic1). This is a description of which function: A) AND B) NAND C) NOT D) NOR

80. Gives a high output when either or both inputs are high. This is a description of which function: A) OR B) AND C) NOT D) NAND

81. Has only one input and one output. The output is always the opposite of the input. This is a description of which function: A) NOT B) NAND C) AND D) NOR

82. Is a combination of OR and NOT. The output is that of an inverted OR gate. This is a description of which function: A) NOR B) NOT C) OR D) NAND

83. Is an AND gate with inverted output which means that a 1 is given when the AND gate would NOT give a 1. This is a description of which function: A) NAND B) NOR C) NOT D) AND

84. Which type of gate does this schematic symbol represent: A) OR B) AND C) NOT D) NAND

85. Which type of gate does this schematic symbol represent: A) NOR B) NOT C) OR D) NAND

86. Which type of gate does this schematic symbol represent: A) NAND B) NOR C) NOT D) AND

87. Which type of gate does this schematic symbol represent: A) AND B) NAND C) NOT D) NOR

88. Which type of gate does this schematic symbol represent: A) NOT B) NAND C) AND D) NOR

89. A component consuming 80 watts at 8 amps would require a supply of:

90. Which of the following statements is correct? 1. By increasing the load on an electric motor (i.e. increasing the resistance against rotation), the power output will increase as a result of an increased current flow. 2. The torque of an electrical motor can be calculated by dividing the power by the motor RPM.

91. Assuming the initiating cause is removed, which of these statements about resetting a protection device are correct or incorrect? 1. A fuse cannot be reset 2. A circuit breaker can be reset

92. Electrical bonding of an aircraft is used to: 1. Protect the aircraft against lightning effects. 2. Ensure an electrostatic potential of the aircraft of approximating 0 volt. 3. Reduce radio interference on radio communication systems. 4. Ensure the different aircraft parts are at the same electrical potential. The combination that regroups all of the correct statements is:

93. Regarding the capacity of a battery and its measurement, which statement(s) ls/are correct/incorrect? 1. The battery capacity is determined by multiplying a current flow in Amperes by the time in hours that the battery is being discharged. 2. The total battery capacity is dependent on the voltage rating of its battery cells.

94. The resistors R1 and R2 are connected in parallel. The value of the total resistance is given by the following formula:

95. When connecting two 12 volt 40 ampere-hour batteries in parallel, what will be their total voltage and capacity?

96. Static dischargers: 1. are used to set all the parts of the airframe to the same electrical potential. 2. are placed on wing and tall tips to facilitate electrical discharge. 3. are used to reset the electrostatic potential of the aircraft to a value approximating 0 volts. 4. are located on wing and tail tips to reduce interference with the on-board radio communication systems to a minimum. 5. limit the risks of transfer of electrical charges between the aircraft and the electrified clouds. The combination that regroups ail of the correct statements is:

97. The voltage of a fully charged lead-acid battery cell is approximately:

98. If a battery's ammeter shows +24 , what is happening?

99. The advantages of alternating current on board an aircraft are: 1. Simple connection. 2. High starting torque. 3. Flexibility in use. 4. Lighter weight of equipment. 5. Easy to convert into direct current. 6. Easy maintenance of machines. The combination of correct answers is:

100. The advantages of Nickel-Cadmium compared with Lead-acid batteries are: 1. Lower risk of thermal runaway. 2. Higher internal resistance, hence higher power. 3. Reduced charging time. 4. Constant output voltage. The combination of the correct statements is:

101. In order to produce an alternating voltage of 400 Hz, the number of pairs of poles required in an AC generator running at 6000 rpm is:

102. The most widely used AC frequency in aircraft is:

103. f a current is passed through a conductor which is positioned perpendicular to a magnetic field:

104. When a conductor cuts the field lines of a magnetic field:

105. A relay is:

106. When carrying out a battery condition check using the aircraft's voltmeter:

107. Electric motors on aircraft can be:

108. A current limiter fuse in a DC system is used to:

109. The capacity of a battery is the:

110. Batteries are rated in:

111. The rating of electrical fuses is expressed in:

112. The unit that converts DC into AC is:

113. The type of gate that requires all 'TRUE' inputs for a 'TRUE' output is:

114. One of the main functions of the battery in large transport aircraft is to:

115. To ensure correct load sharing between AC generators operating in parallel:

116. Given: Q = charge (Coulombs). U = potential difference between the plates (Volt). The capacitance C (Farads) is defined by the following formula:

117. A constant speed drive (CSD) that has been disconnected in flight:

118. A test to assess the state of charge of a Lead-acid battery would involve:

119. The very rapid magnetic field changes (flux changes) in the primary coil of a magneto are accomplished by the:

120. The input and output of a static inverter are respectively:

121. f the frequency of the supply in a series capacitive circuit is decreased, the current flowing in the circuit will:

122. An inverter is a:

123. The purpose of static wick dischargers is to:

124. The purpose of static wick dischargers is to:

125. When the AC generators are connected in parallel, the reactive loads are balanced by means of the:

126. The unit used to measure the capacitance of a capacitor is the:

127. The purpose of a voltage regulator is to control the output voltage of the:

128. The function of the generator breaker is to close when the voltage of the:

129. When the AC voltage across a capacitor is kept constant and the frequency is increased, the current through the capacitor will:

130. The essential difference between aircraft AC alternators and DC generators (dynamos) is that the:

131. A capacitor in parallel with breaker points:

132. The function of a NOT logic gate within a circuit is to:

133. When the battery ammeter shows "+24" the battery:

134. The phase relationship between two unparalleled AC generators:

135. If one of the 12 cells of a Lead-acid battery has a broken connection rendering it inoperable, the battery:

136. What is the unit of measurement for electrical work?

137. The power output of a normally aspirated piston engine increases with increasing altitude at constant Manifold Absolute Pressure (MAP) and RPM because of the:

138. An advantage of nickel-cadmium compared with lead-acid batteries is that they:

139. Frequency wild' in relation to an AC generation system means the generator:

140. When using a fuse with a higher rating than prescribed:

141. DC generators in multi engine aircraft are connected in:

142. ln flight, if the temperature of the constant speed drive (CSD) ls in the red arc the:

143. The electrolyte in a Nickel-Cadmium battery is:

144. A thermal circuit breaker:

145. An AC generator driven by a constant speed drive (CSD):

146. The moving part in an AC generator is usually referred to as the:

147. The purpose of static discharge wicks is to:

148. One indication of inadequate bonding of aircraft components may be:

149. Which of the following formulas describes how the torque of an electrical motor is determined by the supplied voltage and current and the resulting RPM. T = Torque, U = Voltage, H = RPM, I = Current.

150. A capacitor can be used as a:

151. A lithium polymer battery is most likely to be a hazard to the aircraft when:

152. Regarding ohm's law:

153. In the event of an AC generator fault, on a twin engine aircraft, the protection device will open:

154. It is NOT recommended to reset a tripped circuit breaker during flight because:

155. When a battery is almost fully discharged there is a tendency for:

156. In a DC (Direct Current) circuit, what will happen if the current gets too high and ls not detected?

157. In aeronautics, the most commonly used batteries are NiCd because:

158. Circuit breakers protecting circuits may be:

159. The commonly used symbol for voltage is:

160. AC generators operated in parallel must have the same:

161. If we connect two batteries in series what happens to the voltage and capacity?

162. Electrical potential is measured in:

163. ln reference to an inverter unit, which of these relationships between AC and DC is correct?