Electrical System Dgca June 2009

JUNE 2009 ELECTRICAL SYSTEM 1) What type of electrical motor is generally used with a direct cranking engine starter 1) DC shunt wound motor 2) DC series motor 3) Dc compound wound motor 4) fully compound motor 2) In a CRT the three primary colors 1) are generated by 3 electron guns, and pass through a perforated shadow mask so that they strike 3 different kind of phosphorus coating 3) MTCS 1) Anti collision light is designed to give light intensity 30 degree above & below the horizontal 2) as in ‘1’ & the reflector rotation is not less than 40 rpm and giving a frequency of not more than 100 Cps 3) as in ‘2’ & light beacons are 180 degree apart at any instant 4) as in ‘3’ & it permits the position of the a/c to be more readily determined 4) Three equal impedances are first connected in star across a balanced 3- phase supply, if connected in delta across the same supply 1) Power consumed is increased by three fold 2) Power consumed remains same 3) Power consumed is decreased by three times 5) T- connection in transformer is used for 1) 3 phase to 3 phase connection 2) 3 phase to 2 phase connection 3) as in ‘1’ & 3 phase to 2 phase connection & vice-versa 6) Two wattmeter in 2 phase circuit test reads one load is positive & the other load is negative, PF is 1) 0.8 2) 0.5 3) 0.4 4) 0.3 7) Flip flop falls under 1) SSI 2) LSI

3) MSI

4) VLSI

8) R=6 OHMS, XL = 8 OHMS, & 200 VOLT at 50 Hz is applied to the RL circuit what is the voltage drop across 1) 120 volts 2) 200 volts 3) 150 volts 9) Tumbler switch 1) Toggle switch

2) Rocker arm switch

3) Mercury switch

10) A NAND gate is bubbled at its input forms 1) NOR gate 2) AND gate 3) OR gate 11) Emitter Follower is also known as 1) CC 2) CB

3) CE

12) CB configuration can be used in 1) High frequency application

2) as in ‘1’ & for impedance matching

13) For measurement of power at very high frequency and low power which meter is used 1) Thermocouple meter 14) The mica capacitor having color coding of RED, GREEN, BLACK & GREY, the value of capacitance 1) 25 pf 2) 0.25 pf 3) 250 pf 4) 2.5 pf 15) Power transformer is a 1) constant voltage device 3) constant power device

2) constant current device 4) constant flux device

16) While testing the bonding tester 1) 60 feet cable to be connected to the earth point 17) For temperature compensation which capacitor is used 1) Ceramic 2) Mica 3) Chip 4) Electrolyte 18) If electrolyte is added in a new battery, before placing it in cervice it should be allowed to stand for 1) 24 hours 2) 1 hours 3) 6 hours 19) Principal of slugged relay 1) Lenz’s Law 2) Faraday law

3) Coulomb law

20) The relay in magnetic starting switch operates when 1) The starting switch is puts ON 2) Starting switch resistance is bypassed 3) Auxiliary contacts operates 21) Q- factor can be increased by 1) Capacitance 2) Low ohmic resistance

3) large inductance

22)In an auto transformer the output of the secondary is 1) K. input 2) k. output 3) (1-k) input 4) ( 1-k) output 23) The generator rating is 40 KVa with power factor of 0.8 the maximum amount of power that can be dissipated 1) 40 kW 2) 56 kW 3) 4 kW 4) 32 kW 24) For general service wiring the following cables are used 1) NYVIN 2) PREN 3) TERSIL

4) both ‘1’ & ‘2’

25) For position control & speed control mechanism the feedback is by 1) A potentiometer & Tacho generator

26) Maxwell loop current method of solving electrical network 1) Uses branch current 2) utilizes Kirchhoffs Voltage law 3) is confined to single loop circuit 4) is a network reduction method 27) Carbon coating (Aquadag coating) inside a glass tube of CRT is to 1) Absorb secondary emission of electrons 28) In electrical diagrams whill troubleshooting the circuit, the procedure of correct sequence is 1) Schematic, Location, Routing Chart 2) Location, Schematic Routing Chart 3) Routing, Schematic, Location chart 4) Schematic, Routing, Location chart 29) In identification of cables the letter ‘E’ in 2E12 C indicates 1) Engine Control 2) Engine instrument 3) Flight control

4) Flight instrument

30) In a BJT arrowhead indicates 1) hole current 2) electron current 31) In a Lead Acid battery, when a pair of electrons leave the negative side of battery 1) Lead atoms to Lead sulphate 2) Lead peroxide to Lead sulphate 3) Lead sulphate to Lead peroxide 32) Fire wire is identified by 1) Part no only 2) capillary diameter

3) end connection

33) Capacitor is connected across generator terminals for 1) Screening 2) Bonding 3) Earthing

4) none

d) none

34) LRU is used in 1) Landing gear position indicator 35) In an amplifier negative feedback has the advantage of 1) reduced gain, Increase bandwidth 36) In a DC generator ripple can be eliminated by 1) connecting a capacitor filter in parallel 37) In a/c starter generator 1) for starting purposes functions as a fully compound motor & after reaching full speed functions like a shunt DC generator 38) If a transformer designed for a frequency is used on a lower frequency 1) There is a risk of excessive heat generated in the primary winding & subsequent burnout 39)Core material of a magnetic transformer 1) same as transformer 2) saturation is sharp as increased by MMF

40) Smoke in cargo/baggage compartment of a/c 1) Photoelectric cell 2) Sniffer 41) ESD component when taken out from a/c, precaution 1) Connector pin should be shorted 2) Pins should not be touched 3) Both ‘1’ & ‘2’ 42) Bonding can be classified as primary & Secondary 1) the current expected due to electrostatic & precipitation static respectively 43) A parallel AC circuit at resonance 1) Have maximum impedance 44) Under null condition of Wheatstone bridge 1) No current flows in the galvanometer 2) Current flows in the circuit but no current flows in the galvanometer 45) In electrical system of a/c flexible conduit 1) To protect from stones, foreign particles etc. from mechanical damage 2) to avoid interference 3) To eliminate sparking 46) Two magnetic amplifier are connected in push pull configuration to 1) Enhance the sensitivity and zero standing current level 2) provide 180degre phase reversal 3) No phase reversal 47) To find out the fault between the input & output of an IC 1) Logic probe is used 2) voltmeter 3) ‘1’ & ‘2’ 48) the average current of half wave rectifier 1) 0.637 Im 2) 0.707 Im 3) 1.414 Im

4) ‘1’ & continuity tester 4) 0.5 Im

49) MTCS 1) Strobe lighting system is based on the principle of a capacitor discharge flash tube 2) Depending on the size of the a/c strobe lighting may be installed in the wing tips to supplement the conventional red beacon 3) flashing frequency is 70 per minute 4) All & high intensity lighting system 50) In capacitance type fire detection system 1) A short circuit grounding the element does not result in a false fire warning 51) If lead acid battery not retaining charge 1) Electrolyte level below the plate

52) In a/c battery protection is by 1) By using an overheat sensor & cutting rate of charge 53) In anti-skid system reference voltage is taken from 1) Nose wheel 2) Inertial Reference Unit 54) In ESDS 1) isolate the pins

3) Each individual wheel

4) All

2) Shorted the pins

55) Nominal discharge rating of Ni –Cd battery 1) 5 hours discharge by 0.8 volt 3) 7 hours discharge by 0.8 volt

2) 5 hours discharge by 1.0 volt 4) 5 hours discharge by 1.2 volt

56) EPR 1) Turbine inlet & compressor outlet 3) Front of the compressor & rear of the turbine

2) compressor inlet & turbine outlet