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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...