PAPER- III (ELECTRICAL SYSTEM) DGCA AME EXAM-----OCT SESSION-2013
Compiled & edited by: Mohd Ali & Meenu Kumari Email:
[email protected] Mob: +91-8802482422
Date: 15/Mar2014
This Note: This
question paper does not form in anyway the actual part of the DGCA AME Exam Exam and hence requires careful and necessary consultation with the core books. The questions were compiled soon after the particular exam session after collecting from several candidates wh o appeared in the same and are nearly same in order. Though careful consideration & reference has been made with the core books while answering the th e questions, you may still refer the books in case of doubt . 1. Which of the electrical circuit will dissipate more heat : (BLT Page 29 part 1)
a. b. c. d.
Figure a Figure b Figure c Both (b) & (c)
2. Smoke detectors use: a. capacitor discharge tubes b. spot fire detectors c. continuous fire wire elements d. photo diodes
Pallet-page166) (
3. While running, a synchronous motor is compelled to run at synchronous speed because of:(B. L. Thareja Vol II page no 1532, Chapter 38; AC 65-9A, Page-457 ) a. damper winding in its pole faces b. magnetic locking between stator and rotor poles c. Induced emf. in rotor field winding by b y stator flux d. compulsion due to Lenz’s law 4. The speed of a D.C. motor can be controlled by varying: a. Its flux b. Armature circuit resistance c. Applied voltage d. All the above
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B.L Thareja, Page – 321 321
5. In a thermal switch employing steel and invar element actuation of the contacts under increasing temperature condition is caused by: Pallet-223, Chapter 6. a. expansion of the steel element only b. contraction of the invar element only c. expansion of the steel element causing displacement of the in rear element d. none of the above 6. The purpose of dump valve is: a. to release cabin pressure to atmosphere on landing b. to ensure that differential cabin pressure is maintained throughout the flight c. to maintain cabin temperature as per the setting d. none of the above 7. Sulphation in a lead-acid battery occurs due to :a. Trickle charging b. Incomplete charging c. Heavy discharging d. Fast charging 8. The method used to rapidly charge a nickel cadmium battery utilizes :a. constant current and constant voltage b. constant current and varying voltage c. constant voltage and varying current d. none of these 9. The horn in landing gear warning circuit is activated by: a. up lock micro s/w b. down lock micro s/w c. engine throttle operated micro s/w d. all the above 10. The condition for LG system horn to come on is: a. Any one LG is not DOWN & locked b. Any one LG is not UP & locked c. As in (a) and throttle at landing configuration d. As in (b) and throttle at take off configuration 11. Early effect in BJT refers toa. Avalanche break down b. Thermal Breakdown c. Base narrowing d. Zener break down
(Ref. General)
(B.L Thareja, Page-351)
(T.K. Eismin, Page-52)
(Ref. EHJ Pallet, 176 & 177)
(EHJ Pallett,P-177)
BLT-IV page 2218
12. Mark the correct statement, Synchronous motora. Not self stating b. At low speed high efficiency and p. f. > 1 c. Use for centrifugal pump d. All of the above
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BLT-2 Page 1
13. Mark the correct statement regarding wire bu ndle : a. 3 or more wire going together to the same location b. 2 or more wire group going to same location c. 3 or more wire group going to same location
(15A, wire)
14. Mark the correct statement, Anti-collision lightsa. Navigation lights are used to identify an a/c path by observer b. A+ LH & RH lights are of 3 candles & Rear lights are of 5 candles c. A+ LH & RH lights are of 5 candles & Rear lights are of 3 candles d. All of the above 15. Capacity of battery depends ona. Material of electrode b. Size of electrode c. Level of electrolyte D. All of the above
(Pallett Page 21).
16. Where initial current high & circuit contain high capacitive load, safety device used: a. Current Limiter b. Limiting Resister c. High Rupturing Fuse d. Air Fuse
pallett 112
17. In which side equalizer rings are connected when generators are working in parallela. Negative terminal of both generators b. Negative and Positive terminal of the generator c. Positive terminals of both generators
pallett pg 18
18. When full voltage applied on a synchronous motor, Input voltage know as(B.L.Thareja Vol II, Chap 38 Page 1501) a.Breakaway Torque b. Running Torque c.Pull in Torque d.Pull out Torque
19. Two material A and B have resistance Temperature Coefficient of 0.004 and 0.0004 at a temperature, in what proportion A and B join series to produce a circuit having a temperature coefficient of .001? a. 2 b.3 c.4 d. 5 20. Most common cause of false warning in continuous Loop fire detection s ystem a. Improper routing or clamping of loops b. Moisture c. Dents, Kinks or crushed sensor section
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FAA
21. A Mono-stable Multi vibrator circuit – (B.L.Thareja Vol IV, Chap 65 Page 2440) a. b. c. d.
Has no stable state Gives two output pulse for one input trigger pulse Return to its stand by states automatically Has no energy storage element.
22. Varistor is a solid state device it is primarily consist of- : a. Zink oxide b. Carbons c. Metal oxide d. Silicon carbide
(BLT Part 1Page 29)
23. If temperature increases the resistance of …….. Decreases a. Pure metal b. Electrolyte c. Alloy d. All of the above 24. Which is not the part of Secondary Bonding in aircraft: a. Junction Boxes b. Door plates c. Flight Control Surface d. Metal conduit 25.Out of adjustment in voltage regulator due to a. Fault in field excitation b. Internal grounding of coils c. Open circuit in voltage regulator d. All of the above
(Pallett Page 94 Ch-5)
Pallett page 10-11.
26. Mark the correct statement regarding rain replant system Pallett page 179. a. Approximately 5 c.c. fluid flows through the nozzle for approximately 0.25 seconds. b. Approximately 5 c.c. fluid flows through the noz zle for approximately 0.025 seconds. c. None of the above
27. Smoke detectors use: a. capacitor discharge tubes b. spot fire detectors c. continuous fire wire elements d. photo diodes
Pallet-166
28. In a CSD unit, the control cylinder is mechanically coupled to the: a. variable displacement unit b. fixed displacement unit c. governor d. none of the above
Pallet-221
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29. Circuit breakers and fuses are located: a. generally far from the power source b. close to the power source c. at any location compatible to the particular unit d. so as not to be exposed to heat of any kind
Pallet, P-115
30.. Temperature compensation capacitor is made of: a. mica b. chip c. paper d. ceramic
(Ref. Grob., 420)
31. In ATA 100 code wire specification, No. 3 & No. 5 indicates respectively : Pallett- Page-185 a. Circuit function & Cable segment i.e the portion of the cable between two terminals or connections. b. Circuit segment & Cable function i.e the portion of the cable between two terminals or connections. c. Circuit unit number and cable radius measured in AWG. d. Cable numbering which is used to differentiate between cables not having a common terminal in the same ckt and the cable size corresponding to AWG sizes. 32. The Anti-collision beacon that employs a V- shaped reflector is: a. Rotated at about 45 rev/min b. Rotated at 70-75 cycles/min c. Rotated at 80-90 cycles/min d. Rotated at 90-cycles/min 33. If a Lead acid battery is not retaining charge, probable cause may be: a. Set for high charging rate b. Low electrolyte c. Defective cell d. Electrolyte level is below the plate
(Pallett Page 146)
BLT- 1 Page 362 chapter 9
34. While utilizing co-axial cable, it should be secured firmly along its entire length and supporting clamp are placed: (FAA Airmen Question Bank) a. at 1 feet interval b. at 2 feet interval c. at 4 feet interval d. wherever cable defines 35. In aircraft ESDS devices after removing from aircraft & taking for line maintenance: a. ESDS should be shorted by wire b. ESDS should be shorted by shorting-clips c. Both a and b
(Esmin page 274)
36. In a battery, temperature sensing device. (Pallett – Page 27) a. prevents the battery from overcharging b. in the event of a temperature increase it will automatically disconnect the battery from charging c. as in (a) & prevents from thermal runaway d. All of the above
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37. The mechanical power developed by the armature of a D.C motor is equal to: a. armature current multiplied by back e.m.f b. power input minus losses c. power output multiplied by efficiency d. power output plus iron losses
BLT – II page 1028
38. When external AC power is connected to TRU, its output: a. energies d.c. control relay circuits b. is connected to d.c. bus bar to operate d.c. consumers c. both a & b are correct d. is used sparingly on ground
(Ref. EHJ Pallet, 63)
39. Power transformer has : a. voltage constant b. current constant c. power constant d. Main flux constant 40. If an alternator or generator get overloaded a. it will be disconnected from over load circuit b. thermal switch will automatically disconnect it from over load c. overload condition can be reduced by resistance d. Drive shaft will be disconnected automatically
Check!!!!
41. The effect of increasing the length of air-gap in an induction motor will be to increase the : BLT II Page 1309. a. power factor b. speed c. Magnetizing current d. air gap flux 42. In a very simple system, busbars are made up of : a. strips of interlinked terminals b. thick metal strip c. thick metal rod d. Both (b) and (c)
(Pallett- page 76 Chapter 5)
43. In servomechanism, which type of servomotor is usually preferred? a. one phase b. Two phase c. Three phase d. both (a) and (b)
Pallett (motors)
44. Igniter plug has more advantage over spark plug: a. It sustain high voltage than spark plug b. it sustain high current than spark plug c. It has high energy for prolonger time
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45. Which one can be operated both manually and electrically: a. Proximity switch b. Rotating switch
(Palette- Page 99 Chapter 6)
c. Micro-switch d. Thermal switch
46. what indicates the number of circuits each pole can complete through the switch : (Palette- Page 100 Chapter 6). a. Pole b. Throw c. Both (a) and (b) d. Bi-pole 47. Method employed in CRT to generate free electrons: a. Heat energy (Thermionic emission) b. Speed c. Kinetic energy d. Light energy 48. Mark the correct statement related to NPN Transistor: a. Collector is highly doped for supply of carrier b. Base is least doped and has thin layer. C. Emitter has relatively low voltage
49. White crystals on Ni-Cd battery is formed due to: a. Over charging b. Under Charging c. Charge can be checked by voltage test
(BLT Chapter 73- Page 2695)
V.K Mehta Page 755
( Pallett Chap-01 – page 23 )
50. State of charge of Nickel Cadmium battery can be determined by: (Pallett- Chap- 01 Page 23) a. Electrolytic level b. By relative density of the electrolyte c. Battery Voltage check d. Battery voltage on-charge condition and the electrolyte should be at maximum level.
51. A non-return valve fitted in the air inlet prevents: (Pallett Chapter 01 Page 24) a. air from cabin to enters the battery ventilation chamber and continues through to the outside of the aircraft. b. Fumes and gases from escaping into the aircraft when no pressure differentials exist on the ground. c. Leakage of battery fumes by pressure differential.
52. In a faulty circuit with bad insulation:
CHECK!!!
a. Low intensity blub will glow dimly b. No effect on voltage drop c. current will go back to source d. both (a) and (b)
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53. Copper bonding is used on: a. Stainless steel b. Aluminium c. All metals parts d. both (a) and (b)
Esmin page 77
54. In order to achieve the best possible commutation, commutator are employed with: Pallett page 7 a. A support ring, or end frame, that can be rotated to alter the position of the brushes relative to the magnetic neutral axis. b. brushes with short leads or "pigtails" c. Flexible copper braid moulded into the brush during manufacture. 55. If Ni-Cd battery is completely discharged and charged to 140% of charging : a. Deep cycling b. Fresh charge c. Battery cycling 56. Mark the correct statement regarding landing horn: a. Horn reset when thrust lever idle & flap position is up b. horn reset when final phase of landing & flap down position 57. Real load in Alternator can be determined by: a. Varying the speed of drive unit b. varying the value of voltage regulator c. varying the current in the field winding d. None of the above
Pallett
58. Which one is the most accurate type of frequency measuring instrument? a. integrated circuit chip having a clock circuit b. Electro dynamo meter using electromagnetic fields c. Electomagnets using one permanent magnet 59. Mark the correct statement about TRU and static inverter a. TRU is connected to respective DC/AC busbar b. Static inverter directly connected to battery c. TRU connected to the battery d. Static inverter connected to non-essential bus bars, 60. When both the inputs are high and Output are low: a. Positive NOR & Negative NAND b. Positive OR & Negative AND c. Positive NOR & Negative NAND d. Positive NAND & Negative NOR
61. MTCS regarding CB, CE & CC: a. Power Gain: Moderate Highest b. Power Gain: Highest Moderate c. Power Gain: Moderate Lowest
Pallett Page 176
FAA-Jeppessen
(pallet) Check!!!
BLT
BLT Lowest Lowest Highest
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62. a. b. c. d.
Which memory is a read-only memory? Dynamic Static ROM EPROM
Esmin
63. 8-Bit register that store the memory output when a memory read operation is performed, is known as: a. Program counter b.Memory data register c. Memory address register d.Instruction register 64. When a transformer designed for low frequency is used with higher frequency. Palltte 63 a. in this case the primary current will be reduced and the transformer will function normally b. in this case the primary current will be high and there is a risk of excessive heat generation in the primary winding and subsequent burnout. 65. In an intrinsic semiconductor, Fermi level : BLT 4 ch-1 pg 2035 a. Lies in the middle of the energy gap i.e. midway b/w the conduction and valence band. b. Lies in the middle of insulator and semiconductors. 66. Anti-skid system control affected by a. A switch in the cockpit 67. Regarding LED MTCS: a. For an LED to conduct, the applied voltage must be connected in the forward-biased condition b. For an LED to conduct, the applied voltage must be connected in the reversed-biased condition c. None of the above
68. a. b. c. d.
MTCS: When open circuit occur in a circuit, current return into the system When short circuit occur current return to system As in b) & voltage low level condition light brightness is low As in b) and c)
69. The iron loss of a transformer at 400 Hz is low. Assuming that eddy current & hysteresis loss vary as the square of flux density. The iron loss of the Transformer at rated voltage but at 50 Hz would be-------- watt: BLT-1209 a. 80 b. 640 c. 1.25 d. 100 70. In case of magneto system : a. When switch is in ‘OFF’ position, circuit completes to ground. b. When the switch is ‘ON’ condition circuit connects to ground. c. None of the above.
pallett page 158
71. Mercury switch is used for: pallett page 104 a. When the angular position of a component must be controlled within a narrow band of operation. b. The angular position of a component has no effect on the switch.
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72. In the case of CRT:
Esmin
a. The video data received from a radio antenna is conveniently in what is termed – rho theta form. b. Received data is still in rho-theta form but displayed x-y format c. As in a) and b).
73. In the case of split bus bar method: page 81 pallett Check!!! a. Used between non-parallel generator b. In the case both the generator fails the main DC busbar will become isolated from the essential DC busbar
74. a) b) c)
MTCS (bus II amber) when: page 80 pallett If both respective GCB and BTB are open If both respective GCB and BTB are open Either respective GCB and BTB are open
75. In case of servomechanism for correct phase used: a. Phase correction transducer b. Differentiator 76. a. b. c. d.
Autoflight control (servo mechanism)
In case of real load unbalance is determined by means of : Speed governor Error detector Current transformer Magnetic amplifier
Pallet page 48
77. In a generator what eliminates possible sparking to the brush guide caused by the movement of the brush within the holder: FAA a. Brush spring tensions. b. The brush pigtails c. Undercutting of the mica on the commutator 78. The voltage in an ac transformer that contains twice as many as loops as the primary will be: a. Greater & the amperage less than in the primary b. Less & the amperage greater than the primary.
79. In the case of synchronous motor : a. F=PN/60 (P:no. of pairs of poles, N:synchronous speed, F: power-supply frequency ) b. b. F=60/PN c. c. F=P60/N 80. Intrinsic semiconductor at absolute temperature behaves as: a. Conductor b. Insulator c. None of the above
81. a. b. c.
FAA
Pallett page 143
BLT
When constant frequency generators are operating in parallel the shearing of a real load is controlled by : pallet 221 Varying the excitation current in each generator Varying the output speed of the CSD unit By shedding certain load.
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82.The primary reason for providing compensating winding in a DC generator is to: a. Compensate for decrease in main flux b. Neutralize armature mmf c. Neutralize cross magnetizing flux d. Maintain uniform flux distribution
BLT-965
83.The main function if interlope is to minimize ________between the brushes and the commutator when the DC machine is rotated: BLT-965 a. Friction b. Sparking c. Current d. Wear and tear 84.The moving system of an indicating type of electrical instrument is subjected to: a. A deflecting torque b. A controlling torque c. A damping torque d. All of the above
FAA
85.The meter suitable for only direct current measurement is: a. Moving-iron type b. Permanent magnet type c. Electromagnet type d. Hot wire type
FAA
86.The ratio of the true power to the apparent power in an a.c circuit is known as: a. Reactive power b. Power factor c. Real power
Pallett
87.The phase voltage of a three phase star connected a.c generator is: a. Equal to line voltage b. Greater than line voltage c. Less than line voltage
Pallett
More questions with figures: 1. 2. 3. 4. 5.
Identification of coaxial cable Continuous loop detector Hartley and colpitt oscillator Wattmeter Switches (Pole-throw)
Best
of Luck
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