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HAL PAPER - 15 FEB 2009 - BHUBANESWAR


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...



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