ELECTRIC 9.4 P1
75. Increasing the real load primarily A. increases output voltage and increases frequency. B. decreases output voltage. C. decreases frequency.
NIL
77. The power factor of an AC generator identifies the proportion of A. apparent power from the generator that does work. B. real power from the generator that does work. C. reactive power from the generator that does work.
NIL
90. A vibration contact voltage regulator consists of a shunt winding and a A. current regulation coil in series. B. voltage regulating coil in series. C. voltage regulating coil in parallel
NIL
26. During a normal engine shutdown, generator tripping is initiated by A. under voltage. B. underfrequency. C. overcurrent.
a
27. What would you use to neutralise nicad battery spillage?. A. Boric acid. B. Distilled water. C. Bicarbonate of soda.
a
3. When a current transformer is disconnected, what should be done? A. Terminals shorted. B. Resistor placed across terminals. C. Left open circuit.
a
31. Differential protection as applied to AC generation systems compares A. generator current to busbar current. B. generator voltage to busbar voltage. C. ambient pressure to cabin pressure.
a
32. In an AC generation system, the frequency and phase rotation A. must be synchronised prior to paralleling. B. is of no consequence after paralleling. C. must be out of phase prior to paralleling.
a
35. Whilst operating paralleled AC constant frequency generators, it is important to maintain generator outputs at the same voltage A. to prevent a circulating current of considerable magnitude developing between two or more generators. B. to prevent CSD shock loading. C. to prevent a circulating current developing between two or more TRUs.
a
38. The output frequency of a hydraulically driven standby generator is controlled by A. an hydraulically actuated swash plate. B. a CSD. C. an IDG.
a
85. What is the small pin on the DC ground power connector?. A. Positive to external power relay. B. Positive to battery relay. C. Ground or earth.
a
1. A lead-acid battery is considered to be fully charged when the A. cells begin to gas freely. B. SG and voltage remain constant for specified period. C. SG reaches 1.180.
b
16. A diode connected across a coil will A. suppress arching when relay is opening and closing B. prevent back EMF and allow faster switching C. prevent the coil being fitted the wrong way.
b
2. The preferred method of battery charging a Ni-Cad battery is constant A. voltage B. Current C. Power
b
34. Placing the battery master switch to off during flight will A. isolate the battery from the main busbar. B. shut down the APU. C. disconnect all power to the main busbar.
NIL
62. To confirm the state of charge of a ni-cad battery. A. measure the discharge time. B. subject the battery to load, check voltage and check the SG of each cell. C. subject the battery to load and check the voltage.
NIL
71. If an aircraft has no battery charger, the battery is charged by A. constant current until a predetermined limit when it automatically switches to constant voltage. B. constant current. C. constant voltage.
NIL
10. In a multi-generator system, the generator which takes more than its reactive power share is protected by A. over-voltage and under-voltage protection circuits B. over-current and under-current protection circuits C. over-excitation and under-excitation protection circuits
a
100. Load shedding allows A. less current to the busbar. B. more current to the busbar. C. more voltage to the busbar.
a
11. Sharing of electrical loads by paralleled DC generators is controlled by A. equalising circuits which control the field excitation of the generators. B. automatic load shedding C. equalising circuits which control the speed of the generators
a
13. Before checking the SG of a battery recently removed from an aircraft A. take the temperature of the electrolyte. B. carry out a capacity test. C. allow to stabilise for one hour.
a
18. Differential protection in a generating system A. detects current difference between source and load. B. detects voltage difference between source and load. C. uses the volts coil to trip the GCR.
a
19. Open phase sensing on a current transformer A. is detected on generator neutral circuit. B. is detected using all phases. C. is detected using any phase.
a
24. Distilled water should be added to a ni-cad battery A. only in the battery workshop. B. at any time. C. when fully charged.
a
39. An AC generator used with a CSD A. needs a voltage controller to maintain voltage with increasing load. B. does not need a voltage controller because current is kept constant. C. does not need a voltage controller because voltage is kept constant.
a
40. Power to a GCU is supplied. A. initially by a 'field tickling' supply and then PMG output. B. by the battery bus or rectified generator output. C. by the generator output only.
a
43. Wires in hot temperature areas should be bound with A. Teflon. B. Nomex. C. PVC.
a
45. High voltages on a generator in a parallel system should be prevented because A. it will trip the GCR. B. it will damage the drive shaft. C. it will cause high circulating current in the bus / other generators.
a
46. Over-voltage condition trips the generator. The time taken to trip the GCU depends on. A. amplitude of voltage. B. closing of fuel and hydraulic valves. C. time delay circuit.
a
50. When the temperature increases in a lead acid battery, the SG will A. decrease. B. increase. C. remain the same.
a
54. Electrical load on aircraft is controlled by A. a BPCU. B. an IRS. C. a GCU.
a
55. A 4:1 step-up transformer receives 120VAC in its primary and has 1600 Ohms resistance in its secondary. What is the current drawn from the source? A. 1.2 A. B. 0.3 A. C. 3 A.
a
57. Topping up a Ni-Cad battery in situ A. is not allowed. B. is only allowed in the shop. C. is permitted.
a
59. A short range passenger aircraft has complete electrical failure. What time duration would the battery be expected to power essential equipment?. A. 30 minutes. B. Forever. C. 60 minutes.
a
6. Galley loads are wired in A. parallel so load shedding will lower current consumption. B. either series or parallel depending on the design. C. series.
a
61. The purpose of a synchronising bus bar is A. to allow monitoring and trimming from the flight deck. B. to enable two propeller systems to be synchronised. C. to monitor total current load.
a
67. Paralleling is used for A. AC and DC electrical generators. B. DC electrical generators only. C. AC electrical generators only.
a
69. In a carbon pile regulator, the resistive element is A. in series with the field and changes resistance with surface area contact. B. in parallel with the field and changes resistance with changing length. C. in series with the field and changes resistance with changing length.
a
72. The output of a carbon pile regulator with no variation of loading is. A. stationary. B. pulse width modulating. C. fluctuating.
a
73. In a transistor voltage regulator, the voltage output is controlled by A. zeners and transistors. B. diodes and transformers. C. transformers and transistors.
a
76. Inductive reactive load causes. A. no effect on torque but produces extra heat dissipated B. increase in torque only. C. increase in torque and increase in heat dissipated.
a
81. In an undervolt condition in an AC generator system, the most likely consequence is A. activation of the time delay circuit. B. energise the bus tie relay. C. deactivation of the field regulatory TRs.
a
86. How is RAT driven? A. Airstream. B. Compressor. C. Fan.
a
87. How is an aircraft battery rated? A. Ampere hours. B. Joules. C. Watts.
a
92. Eddy currents are A. circulating currents. B. caused by heating effect of the coil. C. caused by resistance of the coil.
a
94. When an overvolt is present on an AC generator system, the tripping circuit. A. trips after a time delay inversely proportional to overvolt amplitude. B. trips after a time delay. C. trips at a set level.
a
99. AC generator output indications are measured in A. KVA & KW. B. KW & KVAR. C. KW.
a
83. Assuming all systems are operating normally, as aircraft electrical load increases, generator output voltage will A. increases and amperage output increases. B. remain constant and amperage output increases. C. decrease and amperage output increases.
a BUT NOT SURE
20. If the battery is switched off in flight, the A. captain's instruments will be powered from the standby bus. B. battery is disconnected from bus. C. generator voltage falls to zero.
b
22. Voltage is controlled by A. the constant speed drive. B. the voltage regulator. C. the swashplate.
b
25. Overflowing electrolyte in a ni-cad battery indicates A. not enough charging current. B. excessive charging current. C. low electrolyte temperature.
b
28. Before operating generators in parallel, their voltages should be matched to prevent A. large circulating currents developing. B. overloading the generator drive and shearing of splines. C. voltage spikes of sufficient magnitude to trigger GCU overvoltage circuits.
b
29. Consumer loads are connected to a busbar A. in series so when loads are shed voltage is reduced. B. in parallel so when loads are shed current is reduced. C. in series so when loads are shed current is reduced.
b
30. A current transformer connected on the neutral star point of a generator is for. A. overload protection. B. differential current protection. C. negative sequence protection.
b
36. A voltage regulator installed in series with a generator field A. uses a voltage coil in series with generator output. B. uses a voltage coil in parallel with generator output. C. uses a current coil in parallel with generator output.
b
41. Trip signals for a GCR are A. overfrequency and undervoltage. B. differential protection and undervoltage. C. underfrequency and overcurrent.
b
42. Abnormal CSD operation is monitored on the flight deck by observing indications of A. low oil quantity / low oil temperature. B. high oil temperature / low oil pressure. C. High oil temperature / low oil quantity.
b
47. Speed of an HMG is controlled by a A. CSD unit. B. swashplate. C. ID unit.
b
48. A permanent magnet should have A. low retentivity, low coercivity. B. high retentivity, low coercivity. C. low retentivity, high coercivity.
b
49. What will happen if the aircraft battery becomes overheated? A. The power supply to the battery charger will be interrupted. B. The battery charger will switch to trickle charge mode. C. The hot battery bus will be disconnected from the battery.
b
52. Control of hydraulically powered emergency electrical generator frequency is A. by CSU. B. by angle of swash plate. C. by IDG.
b
58. In a lead-acid battery after numerous checks, one cell has low reading A. It needs topping up. B. It must be replaced. C. It is defective.
b
60. An external power plug has two short pins. These are used for A. ground handling bus. B. the interlock circuit. C. a guide for correct alignment of the plug in the socket.
b
63. Circulating currents are associated with A. AC and DC generators in parallel. B. AC generators in parallel. C. DC generators in parallel.
b
65. What is the amperage at point '' to the nearest amp? A. 100 Amps. B. 101 Amps. C. 102 Amps.
b
68. Battery charging procedures can be found in ATA A. Chapter 24 Section 21. B. Chapter 24 Section 31. C. Chapter 31 Section 21.
b
70. Maximum battery temperature on charging before protection circuit starts is A. 144 degrees C. B. 144 degrees F. C. 71 degrees F.
b
78. Differential protection in an AC system protects against A. line-line, line-line-line, line-earth faults. B. short circuits. C. a reverse current flowing from the battery.
b
8. When a load is shed from a busbar, the A. busbar voltage decreases B. current consumption from the bar decreases C. busbar voltage increases.
b
80. One of the main purposes of a CSD is to A. prevent engine overload. B. enable generators to be paralleled. C. maintain constant load on the generator.
b
82. If voltage and frequency of the generator drop to zero in flight, it would be an indication that the A. bus tie interlock is inoperative. B. CSD driveshaft had sheared. C. phase sequence detection circuit has operated.
b
84. When installing multiple batteries on aircraft, they are connected in A. series. B. either parallel or series and switched between as an option. C. parallel.
b
88. A reduction in field strength of a DC shunt motor driving a constant load will result in A. reduced torque and increased speed. B. increased torque and speed. C. increased torque and reduced speed.
b
89. What are the 2 short prongs on an AC plug for? A. Using AC current to pull on interlock circuit. B. To prevent arcing during plug connection / disconnection. C. To help plug location/fit.
b
9. In unparalleled AC generation systems, the phase rotation of one generator in relation to the others A. must be synchronised prior to paralleling B. is unimportant C. must be BCA.
b
95. In an AC distribution system, the purpose of the synchronising bus-bar is to A. provide a means of monitoring the load. B. provide interconnection between the generator load busbars. C. supply essential services.
b
98. Zener diodes are for A. voltage stabilisation. B. voltage regulation. C. rectification.
b
12. Excessive commutator sparking can be caused by A. rotating field diode failure. B. brushes positioned on MNA. C. weak spring tension.
c
14. On an AC external power plug, the interlock circuit is controlled by pins A. AB. B. CD. C. EF.
c
15. Over-voltage protection circuits are activated A. before the over voltage limit is exceeded. B. after a fixed time delay. C. dependent on the magnitude of the overvoltage.
c
17. Which fault does not always trip the GCR? A. Under-frequency and under-volts. B. Over-frequency and over-volts. C. Over-frequency and under-frequency
c
21. To flash a generator field the A. generator is on line and producing a voltage less than the flashing voltage. B. generator rotates but is not on line. C. generator must be stationary.
c
23. The ground interlock pins are numbered A. A and B. B. C and N C. E and F.
c
33. Diodes are placed across a contactor to A. ensure smooth contactor operation. B. prevent contact bounce. C. speed up operation by reducing back EMF.
c
37. CSD warning lights on the flight deck normally indicate A. high oil pressure, low oil temperature, low oil pressure, high oil temperature. B. low oil pressure, low oil temperature. C. low oil pressure, high oil temperature.
c
4. What does the differential sensing coil sense? A. Power. B. Volts. C. Current.
c
44. A heat gun should be operated at A. 100°C above the specified. B. 100°C below the specified. C. the specified temperature.
c
5. Where does the GCU gets its power? A. RAT. B. Battery. C. PMG.
c
51. On testing a generator it is found to require adjusting, where would you adjust it? A. In the cockpit on the flight engineers panel. B. On the GCU. C. By means of a remote trimmer.
c
53. When a ni-cad battery is fully charged A. the electrolyte level is higher level than normal. B. the electrolyte level is lower than normal. C. the electrolyte level stays the same.
c
56. After engine start using a Ni-Cad battery, the pilot observes on the battery charger indicator, an initial high current draw followed by a rapid decrease in current A. there is a problem with the charging circuit and he must shut-down the engines. B. the battery is faulty. C. no cause for concern.
c
64. Generator brush bedding A. should only be done if 50% of the width and 80% of the length is already being done. B. should not be done on the aircraft. C. can be done on the aircraft.
c
66. Pitot tubes are heated by A. DC. B. AC. C. AC or DC.
c
7. A fuse-type current limiter A. can be used as a radio suppressor. B. limits current flow to a load. C. opens a circuit after a time/current condition has been exceeded.
c
74. A paralleled relay for a DC system is energised and connected by A. voltage coil. B. current coil. C. voltage and current coil.
c
79. When resetting the CSD on the ground, the engine should be. A. rotating at Nsync. B. rotating at idle. C. stationary.
c
91. What is the purpose of diode in a power GCR? A. To allow flow in the event of failure of the relay. B. To speed up the operation. C. To prevent back-flow of current in the EMF coil.
c
93. The small pins in the power connector plug are A. negative. B. neutral. C. positive.
c
96. Vibrating contact voltage regulator sensing coil is A. across the generator output. B. in series with the field windings. C. in parallel with the field windings.
c
97. A current transformer connected across the neutral of a 3 phase generator is for A. load monitoring. B. phase sequence monitoring. C. differential protection.
c
