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Transcript
Hi friends,, Here are the some of the technical questions appeared in the HAL exam for the post of Executive Engineer on 15-02-2009 for electrical branch.This paper is compiled with the help of M.Eswar Reddy. 1)Finding the power angel in power system 2)The motor used in fruit juicer 3)LVDT is used in finding th displacement 4)Cross magnetization will come with wat pf 5)The type of converter used in HVDC 6)The relationship b/w the airgap and current in light 7)Corrona loss is less in which type of shaped conductor?( the question is asked 2 times) Ans: circular 8)The motor used in low speed applications? 9)If the accuracy of an instrument is 5% for 100A current ,accuracy for 50A current? 10)A question on time constant of a coil(R-L) circuit! 11)Effect of line commutated inductance in inverter a) increase current ripple b) reduces current ripple c) increases output voltage d) reduces output voltage 12)The type of bridge is used for Low Q applications ans: maxwells bridge 13)A question on PSM and TSM in power system 14)The advantage of PI controller over P controller 15)The power gain is highest in wat amplifier Ans : common emitter 16)Power of a converter with ac input supply and dc output current a)1 b)0.98 c)0.95 d)0.92 17)The element which has unchanged properties when current direction is reversed a)linear b)bilateral Ans: b 18)The output voltage is high in wat rectifier a) HWR b) FWR .... 19)Problem on power factor..a load is given and synch motor is given..sych motor is taking 10kw input, load is 00MVA and 0.8lag,synch motor is running on no load..to bring power factor to '1' the synch motor should supply how much eactive VAR? 20)A question on current source and voltage source inverter power transformer is earthed becoz.. a) to reduce neutral current b)to avoid harmonics c)... 21)Why generator neutral is earthed with transformer neutral? Ans: generator stator winding protection 22)Positive sequence terminal voltage is zero in a)L-L b)L-L-G c)L-G d)L-L-L Ans: d 23)A bit on finding the voltage drop in the line when the supply voltage and line reactance and VARs supplied to the load in p.u. 24)Pulse transformer is used in thyristor because? 25)The advantage of linear power supply over switched mode power supply? a)low cost b)low noise c)low weight 26) The stability when there are slow changes in load Ans: steady state stability 27)A question on finding the step angle of a stepper motor 28)A question on construction of hybrid motor 29)Which answer is not true in case of squirrel cage IM a)resistance is low b)the cross section of copper conductors is low c)... d)none of the above Ans: a 30) To increase starting torque of SRIM Ans: add resistance 31) Which torque is maximum in stepper motor a) starting torque b) pullout torque c) hybrid torque 32) The similarity b/w in 8086 and 8088 Ans: data bus(16bit) 33) The location transferred by the processor when INTR is enabled Ans: it wont go to any location since it is non vectored inturrept 34) The starting torque relation b/w DOL starting and star-delta starting Ans: star delta starting torque is 1/3 times lower 35) THD in full wave rectifier? 36)A question on third harmonic power in full wave converter 37) Element of high negative temp coeff a)chromium... 38) In parallel with each of the main breaks is a low ohmic resistor which is used for Ans: reducing the rate of rise of the recovery voltage during an interrupting operation 39)Recovery voltage of a circuit breaker is defined as Ans: instantaneous value of the supply voltage when the current is interrupted 40)A question on different types of FACTS 41)Kelvin double bridge is used for measurement of? ans: low resistance 42)Speed control of IM using slip change method a) using freq b) using changing the no. of poles c) cascade control 43) Two cycles are there in in oscilloscope..then the freq ration x and y axix( lissajous figure ) 44)What is the universal gate a) and b) not c) Exor d) nor Ans: d 45)Fleming's left hand rule is used for? Ans : dc motor 46)A question on circuit breaker operating time( time between relay command and opening of the contacts of CB) 47)Given reactance of a line 4%, asked the short circuit capacity Ans: 25 times rated current 48)By keeping applied voltage constant if freq is decreased Ans: iron losses increases 49)When 3 phase induction generator is stable a) rotor rotating at less than synch speed b) rotor rotating at higher than sych speed ... 50)Why rotor bars are skewed in IM Ans: to reduce locking tendency 51) Large size alternators are excited with? 52) The time taken by the gas turbine to come into normal speed after it is stopped a)1hr b)30min ... 53)Most economical load in underground cable a) less than surge impedance b) equal to surge impdance c) more than surge impedence 54) Given load factor and plant factor and given maximum demand, they have asked to find out the reserve capacity 55) A question on power measurement when the current coil and voltage coil are connected in weird manner :) 56) The SI unit of power 57) Conductor size is based on ? a) depeding upon the transmission line distance b)... Ans: might be 'a' 58) Which of the following transformers can be connecte in parallel a) delta-delta, delta-star b) delta-star , star-star c) delta-delta , star-star d) delta-star, star-delta 59) Compensating coil is connected in wat way in lpf wattmeter Ans: around CC and in series with the PC 60)The input impedance is in the range of ____ in Digital Volt Meter Ans: in Mega Ohm 61) The input and output impedance of an ideal opamp 62)Two resistances are connected in series and parallel manner..and the values of overall series and parallel connections is given and then asked to find out the two resistances. 63) Question on finding the power angle when the input to the generator is increased 64) Ferranti effect is obtained when? Ans: when the sending voltage is less than receiving voltage 65) Which type of logic family used in Ans: Emitter coupled Logic 66) A ckt is given and asked to find whether ckt is astable multivibrator or bistable...