Published by Roma Rahul Gupta for Chhattisgarh Online
HAL PREVIOUS EXAM PAPER for Electrical check here:
This previous paper is totally based on candiadate's experience.
The test consists of 160 qs. Duration is 150 min .
First section 20 qs related to General awareness and English
Second section 20 Qs related to mental ability and Quantitative ability.
Third section 120 Qs purely related to your Technical subjects .
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...
*********2008 year********
When length of a wire increases its resistance
a. doubles b. half c. remains same
Ans: ( a )
2. When a 50 Hz ,6-pole Induction Motor runs at 975rpm,the rotor emf frequency is
a. 12.5Hz b. 1.25Hz c. 4Hz
Ans: ( b )
3. When a 6 pole 50Hz Induction Motor runs at 1450 rpm , it’s working mode is
a. motoring b. braking c. generating
Ans: ( a )
4. Slips for Different modes of operation of Induction Motor are
answer: motoring -01
Damping ratio ( ? ) is 0.75, natural frequency is 12 rad/s are given & asked to find peak time
In electrodynamo-meter type wattmeter
a. pressure coil is made fixed
b. current coil is made fixed
c. both the coils are made fixed
Ans: ( a )
In flux meter control torque is produced by
a. weights attached to it.
b. Springs
c. No control torque is there
Ans: ( c )
One question regarding hot wire instrument
In MI meters deflecting torque is proportional to
a. square of the current
b. square of the voltage
Ans: ( a )
In 3-F system total power is given by
a. v3VLILcos F
b. 3VLILcos F
c. VLILcos F
Ans: ( a )
From supply one 3-F step-down transformer is drawing 10 A, the secondary current will be minimum when the transformer is
a. star-delta
b. delta-star
c. delta-delta
d. star-star
Ans: ( b )
Transformer rating is expressed in
a. KVA
b. KVAR
c. KW
Ans: ( a )
Manganin is a
a. Insulator
b. Semi-conductor
c. Alloy
Ans: ( I think it is alloy )
Dual scope oscilloscope has
a. two separate horizontal and two separate vertical plates
b. one horizontal and two separate vertical plates
c. two separate horizontal and one vertical plates
d. one horizontal and one vertical plates
Standard Cell voltage is measured by
a. MI meter
b. MC meter
c. Potentiometer
The input resistance of the CRO is of the order of
a. tens of ohm
b. mega ohm
c. kilo ohm
d. fraction of an ohm
Ans: ( b )
Errors are introduced in Wheatstone bridge due to
a. lead resistance
b. contact resistance
c. some thing is given
d. all of the above
Ans: ( I think d )
HRC fuse and circuit-breaker combination is used CB operates for
a. low over-load currents
b. high over-load currents
c. combination is never used
Ans: ( I think a )
G(s) = K / s(s+5)(s+1) is given to find the value of K for stable operation
By increasing gain of the system root locus will
a. moves away from poles
b. moves away from zeros
c. crosses imaginary axis
Ans: ( a )
When the load current is high while measuring power using wattmeter
a. current coil is connected near load
b. pressure coil is connected near load
C = 0.01µF and L = 1 mH and current is 10 A and asked to find the voltage drop
Transmission line is terminated by R and no reflection is there , then the value of R is _________
Ans: 400 ohm
One question regarding shunt ohm-meter and seriea ohm-meter
Inverted V curves are drawn between ________
Ans: field current Vs power factor
Copper loss and Iron loss are given and asked to find at what fraction of full load max.efficiency occurs ( easy to solve )
Aroud 3-4 questions from errors by giving resistance values with their standard deviation like 15 ± 5 % asked to find out the series combination error and parallel combination error likewise
Odd man out in aptitude about two questions
In reasoning finding the next diagram in series
One Antonym
Mainly you should perfect in tenses for solving English questions
These are the questions I have remembered from my paper, I think major share in my question paper is from measurements and next AC machines
ALL THE VERY BEST
Raj psn
Time: 12:30-15:00
Venue: Narayanamma Institute of Technology, Hyderabad
Some of the questions from my paper are given below:
When length of a wire increases its resistance
a. doubles b. half c. remains same
Ans: ( a )
2. When a 50 Hz ,6-pole Induction Motor runs at 975rpm,the rotor emf frequency is
a. 12.5Hz b. 1.25Hz c. 4Hz
Ans: ( b )
3. When a 6 pole 50Hz Induction Motor runs at 1450 rpm , it’s working mode is
a. motoring b. braking c. generating
Ans: ( a )
4. Slips for Different modes of operation of Induction Motor are
answer: motoring -01
Damping ratio ( ? ) is 0.75, natural frequency is 12 rad/s are given & asked to find peak time
In electrodynamo-meter type wattmeter
a. pressure coil is made fixed
b. current coil is made fixed
c. both the coils are made fixed
Ans: ( a )
In flux meter control torque is produced by
a. weights attached to it.
b. Springs
c. No control torque is there
Ans: ( c )
One question regarding hot wire instrument
In MI meters deflecting torque is proportional to
a. square of the current
b. square of the voltage
Ans: ( a )
In 3-F system total power is given by
a. v3VLILcos F
b. 3VLILcos F
c. VLILcos F
Ans: ( a )
From supply one 3-F step-down transformer is drawing 10 A, the secondary current will be minimum when the transformer is
a. star-delta
b. delta-star
c. delta-delta
d. star-star
Ans: ( b )
Transformer rating is expressed in
a. KVA
b. KVAR
c. KW
Ans: ( a )
Manganin is a
a. Insulator
b. Semi-conductor
c. Alloy
Ans: ( I think it is alloy )
Dual scope oscilloscope has
a. two separate horizontal and two separate vertical plates
b. one horizontal and two separate vertical plates
c. two separate horizontal and one vertical plates
d. one horizontal and one vertical plates
Standard Cell voltage is measured by
a. MI meter
b. MC meter
c. Potentiometer
The input resistance of the CRO is of the order of
a. tens of ohm
b. mega ohm
c. kilo ohm
d. fraction of an ohm
Ans: ( b )
Errors are introduced in Wheatstone bridge due to
a. lead resistance
b. contact resistance
c. some thing is given
d. all of the above
Ans: ( I think d )
HRC fuse and circuit-breaker combination is used CB operates for
a. low over-load currents
b. high over-load currents
c. combination is never used
Ans: ( I think a )
G(s) = K / s(s+5)(s+1) is given to find the value of K for stable operation
By increasing gain of the system root locus will
a. moves away from poles
b. moves away from zeros
c. crosses imaginary axis
Ans: ( a )
When the load current is high while measuring power using wattmeter
a. current coil is connected near load
b. pressure coil is connected near load
C = 0.01µF and L = 1 mH and current is 10 A and asked to find the voltage drop
Transmission line is terminated by R and no reflection is there , then the value of R is _________
Ans: 400 ohm
One question regarding shunt ohm-meter and seriea ohm-meter
Inverted V curves are drawn between ________
Ans: field current Vs power factor
Copper loss and Iron loss are given and asked to find at what fraction of full load max.efficiency occurs ( easy to solve )
Aroud 3-4 questions from errors by giving resistance values with their standard deviation like 15 ± 5 % asked to find out the series combination error and parallel combination error likewise
Odd man out in aptitude about two questions
In reasoning finding the next diagram in series
One Antonym
Mainly you should perfect in tenses for solving English questions
These are the question I think major share from measurements and next AC machines.
1) the purpose of feedback transformer & diode in complementary commutated inverters is to-
2) in order to obtain static voltage equalization in series connected SCR’s connection r made of- (this question repeated)
(i.e. 2 times same question Haaa)
3) in phase controlled rectification PF=
4) Why sector winding is used in synchronous motor?
5) A calculation of making current where MVA & KV was given.
6) The o?p voltage e1 & e2 of 2 full-bridge inverters added using o/p transformer. In order to eliminate 5th harmonic from o/p voltage,
the phase angle between e1&e2 will be-
7) A single phase fully controlled line commutated ac-dc converter operates as an inverter when-
8) An SCR has half cycle surge current rating of 3000A for 50Hz. One cycle surge current will be. (double of that)
9) When compared to an symmetrical thyristor, the turn off time & reverse blocking voltage of an asymmetrical thyristor will be-
10) A step-up chopper is feed from an 220v dc source to deliver a load voltage of 66o v. If the non conducting time is 100micro-sec
then reqd pulse width will be. (get duty cycle only)
11) There were some 5-6 numerical problems which I could not remember totally but they consist of firing angle & power transfer
of inverter, SCR. Go llok for that.
12) Relay current setting & Ct ratio was given you have to find out Relay Pick up Current.
13) One question from Dc shunt motor- like a resistance is added of 4.5 ohm in series with arm where rest of arm is 0.5 ohm.
Machine is supplied 220v. find out the null current.
14) In aptitude part see through series completion there was a 5-6 no of that.
15) No aptitude questing like avg, %, proff-loss, prob, etc.
16) Sentence correction 2-3.
17) Why rotor of SCIM is skewed?
18) Magnetostriction increases-
19) Good transformer oil contains how much amount of water in ppm?
20) Lightning over voltage create how much volt?
21) K/s(s+1)(s+5) then find out the value of K so that system become stable.
22) There was a question from definition of Nyquist criteria.
23) Standing done up to the frequency range of? (audio)
24) If a square waveform if given to the supply side of a 2wdg transformer its o/p waveform will be-
25) SC test done on transformer because-
26) If a transformer is operating in .8 PF lag & at efficiency of .9, if now P is .8 lead the efficiency will become.
27) Interpoles are connected for?
28) Dielectric strength of air-
29) A alternator is connected to a grid. Now its prime mover is go slow by ½. Change in its exiting current to held in synchronism.
30) Is the strength of capacitor in LPF is increased the op voltage will-
31) The voltage of a generator and an infinite bus are given 0.92, 10 deg & 1.0, 0 deg resp. the generator acts as a –
32) A wave will not experience any reflection when impedance of line is equal to- surge imp
33) Power transmitted is related to system voltage as-
34) Delay creator ckt name (multivibrator name actually)
35) In tachogenerator adjustment is done by-
36) Surge wave is attended by- (C,L,R)
37) there was 10 question related to measurement-
38) Read all electrostatic instrument related question from any competitive exam book.
39) Lowest reading in moving iron meter is-
40) In galvanometer damping is provided by-
41) In electrodynamic meter a battery & a resistance is provide for-
42) Megger is used for-
43) A question like an ac is applied against a moving coil meter it will reads-
44) Rectifier type instrument measureswhat value - (Rms)
45) Advantage of electrostatic instrument is-
46) Creeping occurs because-
47) Why 2 holes are drilled oppositely in disc of energy meter.
48) Energy meter is a _____ type equipment (recording)
49) There was a question related to selection of a voltmeter based on accuracy-
50) Advantage of hay bridge over anderson bridge-
51) Inductance is measured by – (all the 3 bridge name) .
52) Potentiometer is which type of instrument-
53) Which type of motor is used in refrigerator?
54) Reflection coefficient based problem 1
55) Corona’s advantage-
Technical papers covers 70% frm
Measurement & Instrumentation, Electrical Machine( 90% will be problems) rest frm Power system, power electronics n Control system question type was like this...
1.Find the effective speed of two generator when they operating in parallel with freq. of 50 Hz n 40 Hz? (3600rpm, 500 rpm,3000rpm)
2.question based on deflection torque.
3.Measurent of power by two watt metermethod?
4.Identify type by pu value 0.3,0.3,0.6? (Syn gen., tranmission line, motor)
5.Find the actual reading of voltmeter if error % is given?
6. Pattern in CRO?
7.what to do 4 converting sine wave 2 triangular wave? ( integrating, differntiating, etc)
8.question based on deletion torque of tangent galvenometer?
9.Detection of microwave? (LED, heat, etc)
10.problem based on Sensitivity of bridges, ammeter, voltmeter etc/
11.problem based on rotor resistance n rotor frequency?
12.If a ammeter shows 4A ,suddenlt its downward coil cuts then it will show? ( zero defletion, full sclae, 2A,8A)
13.question based on damping?
14.question on PMMC?
15.loss which wont occur if permamnat magnet is used? options(Hysteriess, eddy curreny, stray,etc)
16.wave shape of aramture mmf? (sine wave, square wave, triangular wave, etc)
17.emf in a conductor is directly proptional to ?( pole-no. of condutor-flux, speed-pole-turns,flux- pole-etc)
18.problem on finding firing angle?
19.whats is the order of jacobian matrix for given no. of bus bar?
20.question based on cyclo converter?
21.queston on measurement of rms?
22.question on electrostatic, electromagnetic, MC, MI instruments?
23.how many watt meter required to measure 3phase 4 wire system? (4,3,2,1)
24.what shud be the range of voltmeter to measure 100v? (100v-1mA,100v-2mA, etc)
25.series n paralell connection of volmeter n ammeter?
26.question on critiacl damping
27.what will be p.f in two watt meter method? (0.5,1,0.8,etc)
28.question on parameter for ABCD line constant
29.triangular spacing of conductors
30.question on hot wire instruments
31.finding full scale deflection
32.question on earthing transformer
33.problem on thermisters
34.problem on syn. gen
35.stability in control system
1) What is the distance between the EHV lines?
a)8m b)11m c)4m d)14m
2) At present how many HVDC lines are there in india?
a)none b)one c)two d)more than two
3) Where is the nuclear located in following places?
ans: i dont remember the answers, but one of them is thalcher(orissa)
4) What is the approximate peak overshoot for a unity feedback system with damping factor 0.6?
a)10% b)5% c)15% d)20%
5) What is the distance between the EHV lines and earth?
a)8m b)11m c)18m d)15m
6) On no load in EHV lines what is the relation between receinving and sending end voltage?
ans: receiving end voltage > sending end voltage
7) What is the surge impedance loading of 400kv line?
ans: 4002/400ohms =400watts
8) similar question with surge impedance given as 160 ohms
ans: 1000watts
9) If both the juctions of transistor are forward biased, in wat region transistor works
ans: saturation region
10) Where is the hydel power plant located in following places?
ans: I dont remember the places
11) self GMD is used in the calculation of_______
a) inductance only
b) inductance and capacitance
c) capacitance only
d) none
12) What is the GMD if the distance between the lines are 6m,6m,12m?
ans: 7.058m( approx)
13) Zero sequence currents doesn't exist in the following fault
a) L-G
b) L-L
c) L-L-G
d) L-L-L-G
Ans: d
14) To avoid arcing connect sutable value of ________ in earthing.
a) capacitance
b) indunctance
c) resistance
d) susceptance
15)There are two to three questions based on Laplace and Inverse Laplace transforms
16)In the following type of conductors the corona is minimum
a) circular
b) stranded
c) helical
d) rectamgular
ans: c
17)When do two wattmeters show same value of opposite readings in two wattmeter method
a) 300 lag
b) 600 lag
c) between 600 and 900 lag
d) zpf lag
ans: d
18) Schering bridge is used to measure
a) frequency
b) inductance
c) capacitance
d) mutual inductance
and: c
19) What is the value of resistance when both length and diameter of the wire are doubled?
ans: halved
20) There is one questions asked on euler's formula..
21) What is the Laplace transform of unit ramp signal?
ans:1/s2
22) What happens to the value of inductance when self GMD is doubled?
23) At what frequency corona loss is more?
a) 50Hz
b) 60Hz
c)
d)
24) What is the largest rating of alternator manufactured in india?
a) 1000MW
b) 500MW
c) 1200MW
d) 250MW
ans:b
25) The response of an RLC circuit for impuse input?
a) exponentially raising
b) sinusoidal
c) exponential falling
d) parabolic
ans: c
26) What is the easier method for finding no. of poles in the right half of s-plane?
a) Niquist plot
b) R-H criterion
c) Root-Locus method
d) Polor plot
ans: b
27) How many no of poles located in the right half of s-plane for the characteristic equation...
28) Burden of current transformers is measured in..
a) Watts
b) Volt Amperes
c) Ampere Hours
d) Joules
29)What is the gate used to get high output when all the inputs are low?
a) NOR
b) NAND
c) Ex-OR
d) Ex-NOR
ans: b
30) Large no of thyristors are used in HVDC transmission to improve______
a) current rating
b) voltage rating
c) Thyristers are available at high ratings
d)
31) What is the line current of a circuit when the current transformer of 1000:5 rating measures 4Amperes?
ans: 800A
32) If the time delay of relay with TMS setting 0.1 is 10 sec, then what is the time delaty when the TMS setting is changed to 0.5
33) How many no of flip-flops are required to get 16 bit counter?
34) _________is connected to reduce frequency errors in ammeter.
a) shunt capacitor
b) series inductance
c) shunt inductance
d)
35)What is the value of ripple factor in Half Wave Rectifier?
a) 1.11
b) 0.8
c) 1.21
d)
36)The principle used in megger?
a) electrostatic effect
b) magnetic effect
c) Induction effect
d)
37)In electrodynamometer type wattmeter the error is due to..
a) pressure coil inductance
b) pressure coil resistance
c)
d)
38) In the following locations where is hydal power plant is not located?
ans: i dont remember the places
39) In distribution lines_____
a) X/R<0.1 b) X/R>10
c) X/R>1
d) X/R<0.01
40) In EHV lines _____
a) X/R=10
b) X/R=100
c)
d)
41) What is the speed of 2 pole alternator at 50Hz frequency?
ans: 3000rpm
42) What is the equivalent decimal no of (624)8
43) What is the binary equivalent of 6.25
44) What is the value of A+AB+B¯ ( B bar)
ans: 1
45) What are the avg and rms values of full wave rectifier
ans: 2Vm/pie, Vm/21/2
46) There is one question based on rank of matrix
47) What is the equivalent of cos(wt+18.750)
a) sin(wt+71.250)
b) sin(wt-71.250)
c) sin(wt+18.250)
d) sin(wt-18.250)
48) The three harmonics will be in phace with each other?_____
a) 3,5,15
b) 2,4,6
c)
d)
ans: a
49) The line current will be equal to phase current in______
ans: delta connection
50) In windmills the frequent problems occur in______
a) mechanical system
b) blades
c) electrodynamic system
d) electric system
51) The machine used in windmills is______
a) alternator
b) induction generator
c)
d)
ans: b
52) Insulators in EHV lines are designed based on_____
a) switching voltages
b) peak voltages
c) corona
d) lightning voltages
ans: a
53) The value of restriking voltage depends on______
a) inductance of line
b) capacitance of line
c) both
d) none
HAL PREVIOUS EXAM PAPER for Electrical check here:
This previous paper is totally based on candiadate's experience.
The test consists of 160 qs. Duration is 150 min .
First section 20 qs related to General awareness and English
Second section 20 Qs related to mental ability and Quantitative ability.
Third section 120 Qs purely related to your Technical subjects .
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...
*********2008 year********
When length of a wire increases its resistance
a. doubles b. half c. remains same
Ans: ( a )
2. When a 50 Hz ,6-pole Induction Motor runs at 975rpm,the rotor emf frequency is
a. 12.5Hz b. 1.25Hz c. 4Hz
Ans: ( b )
3. When a 6 pole 50Hz Induction Motor runs at 1450 rpm , it’s working mode is
a. motoring b. braking c. generating
Ans: ( a )
4. Slips for Different modes of operation of Induction Motor are
answer: motoring -0
Damping ratio ( ? ) is 0.75, natural frequency is 12 rad/s are given & asked to find peak time
In electrodynamo-meter type wattmeter
a. pressure coil is made fixed
b. current coil is made fixed
c. both the coils are made fixed
Ans: ( a )
In flux meter control torque is produced by
a. weights attached to it.
b. Springs
c. No control torque is there
Ans: ( c )
One question regarding hot wire instrument
In MI meters deflecting torque is proportional to
a. square of the current
b. square of the voltage
Ans: ( a )
In 3-F system total power is given by
a. v3VLILcos F
b. 3VLILcos F
c. VLILcos F
Ans: ( a )
From supply one 3-F step-down transformer is drawing 10 A, the secondary current will be minimum when the transformer is
a. star-delta
b. delta-star
c. delta-delta
d. star-star
Ans: ( b )
Transformer rating is expressed in
a. KVA
b. KVAR
c. KW
Ans: ( a )
Manganin is a
a. Insulator
b. Semi-conductor
c. Alloy
Ans: ( I think it is alloy )
Dual scope oscilloscope has
a. two separate horizontal and two separate vertical plates
b. one horizontal and two separate vertical plates
c. two separate horizontal and one vertical plates
d. one horizontal and one vertical plates
Standard Cell voltage is measured by
a. MI meter
b. MC meter
c. Potentiometer
The input resistance of the CRO is of the order of
a. tens of ohm
b. mega ohm
c. kilo ohm
d. fraction of an ohm
Ans: ( b )
Errors are introduced in Wheatstone bridge due to
a. lead resistance
b. contact resistance
c. some thing is given
d. all of the above
Ans: ( I think d )
HRC fuse and circuit-breaker combination is used CB operates for
a. low over-load currents
b. high over-load currents
c. combination is never used
Ans: ( I think a )
G(s) = K / s(s+5)(s+1) is given to find the value of K for stable operation
By increasing gain of the system root locus will
a. moves away from poles
b. moves away from zeros
c. crosses imaginary axis
Ans: ( a )
When the load current is high while measuring power using wattmeter
a. current coil is connected near load
b. pressure coil is connected near load
C = 0.01µF and L = 1 mH and current is 10 A and asked to find the voltage drop
Transmission line is terminated by R and no reflection is there , then the value of R is _________
Ans: 400 ohm
One question regarding shunt ohm-meter and seriea ohm-meter
Inverted V curves are drawn between ________
Ans: field current Vs power factor
Copper loss and Iron loss are given and asked to find at what fraction of full load max.efficiency occurs ( easy to solve )
Aroud 3-4 questions from errors by giving resistance values with their standard deviation like 15 ± 5 % asked to find out the series combination error and parallel combination error likewise
Odd man out in aptitude about two questions
In reasoning finding the next diagram in series
One Antonym
Mainly you should perfect in tenses for solving English questions
These are the questions I have remembered from my paper, I think major share in my question paper is from measurements and next AC machines
ALL THE VERY BEST
Raj psn
Time: 12:30-15:00
Venue: Narayanamma Institute of Technology, Hyderabad
Some of the questions from my paper are given below:
When length of a wire increases its resistance
a. doubles b. half c. remains same
Ans: ( a )
2. When a 50 Hz ,6-pole Induction Motor runs at 975rpm,the rotor emf frequency is
a. 12.5Hz b. 1.25Hz c. 4Hz
Ans: ( b )
3. When a 6 pole 50Hz Induction Motor runs at 1450 rpm , it’s working mode is
a. motoring b. braking c. generating
Ans: ( a )
4. Slips for Different modes of operation of Induction Motor are
answer: motoring -0
Damping ratio ( ? ) is 0.75, natural frequency is 12 rad/s are given & asked to find peak time
In electrodynamo-meter type wattmeter
a. pressure coil is made fixed
b. current coil is made fixed
c. both the coils are made fixed
Ans: ( a )
In flux meter control torque is produced by
a. weights attached to it.
b. Springs
c. No control torque is there
Ans: ( c )
One question regarding hot wire instrument
In MI meters deflecting torque is proportional to
a. square of the current
b. square of the voltage
Ans: ( a )
In 3-F system total power is given by
a. v3VLILcos F
b. 3VLILcos F
c. VLILcos F
Ans: ( a )
From supply one 3-F step-down transformer is drawing 10 A, the secondary current will be minimum when the transformer is
a. star-delta
b. delta-star
c. delta-delta
d. star-star
Ans: ( b )
Transformer rating is expressed in
a. KVA
b. KVAR
c. KW
Ans: ( a )
Manganin is a
a. Insulator
b. Semi-conductor
c. Alloy
Ans: ( I think it is alloy )
Dual scope oscilloscope has
a. two separate horizontal and two separate vertical plates
b. one horizontal and two separate vertical plates
c. two separate horizontal and one vertical plates
d. one horizontal and one vertical plates
Standard Cell voltage is measured by
a. MI meter
b. MC meter
c. Potentiometer
The input resistance of the CRO is of the order of
a. tens of ohm
b. mega ohm
c. kilo ohm
d. fraction of an ohm
Ans: ( b )
Errors are introduced in Wheatstone bridge due to
a. lead resistance
b. contact resistance
c. some thing is given
d. all of the above
Ans: ( I think d )
HRC fuse and circuit-breaker combination is used CB operates for
a. low over-load currents
b. high over-load currents
c. combination is never used
Ans: ( I think a )
G(s) = K / s(s+5)(s+1) is given to find the value of K for stable operation
By increasing gain of the system root locus will
a. moves away from poles
b. moves away from zeros
c. crosses imaginary axis
Ans: ( a )
When the load current is high while measuring power using wattmeter
a. current coil is connected near load
b. pressure coil is connected near load
C = 0.01µF and L = 1 mH and current is 10 A and asked to find the voltage drop
Transmission line is terminated by R and no reflection is there , then the value of R is _________
Ans: 400 ohm
One question regarding shunt ohm-meter and seriea ohm-meter
Inverted V curves are drawn between ________
Ans: field current Vs power factor
Copper loss and Iron loss are given and asked to find at what fraction of full load max.efficiency occurs ( easy to solve )
Aroud 3-4 questions from errors by giving resistance values with their standard deviation like 15 ± 5 % asked to find out the series combination error and parallel combination error likewise
Odd man out in aptitude about two questions
In reasoning finding the next diagram in series
One Antonym
Mainly you should perfect in tenses for solving English questions
These are the question I think major share from measurements and next AC machines.
1) the purpose of feedback transformer & diode in complementary commutated inverters is to-
2) in order to obtain static voltage equalization in series connected SCR’s connection r made of- (this question repeated)
(i.e. 2 times same question Haaa)
3) in phase controlled rectification PF=
4) Why sector winding is used in synchronous motor?
5) A calculation of making current where MVA & KV was given.
6) The o?p voltage e1 & e2 of 2 full-bridge inverters added using o/p transformer. In order to eliminate 5th harmonic from o/p voltage,
the phase angle between e1&e2 will be-
7) A single phase fully controlled line commutated ac-dc converter operates as an inverter when-
8) An SCR has half cycle surge current rating of 3000A for 50Hz. One cycle surge current will be. (double of that)
9) When compared to an symmetrical thyristor, the turn off time & reverse blocking voltage of an asymmetrical thyristor will be-
10) A step-up chopper is feed from an 220v dc source to deliver a load voltage of 66o v. If the non conducting time is 100micro-sec
then reqd pulse width will be. (get duty cycle only)
11) There were some 5-6 numerical problems which I could not remember totally but they consist of firing angle & power transfer
of inverter, SCR. Go llok for that.
12) Relay current setting & Ct ratio was given you have to find out Relay Pick up Current.
13) One question from Dc shunt motor- like a resistance is added of 4.5 ohm in series with arm where rest of arm is 0.5 ohm.
Machine is supplied 220v. find out the null current.
14) In aptitude part see through series completion there was a 5-6 no of that.
15) No aptitude questing like avg, %, proff-loss, prob, etc.
16) Sentence correction 2-3.
17) Why rotor of SCIM is skewed?
18) Magnetostriction increases-
19) Good transformer oil contains how much amount of water in ppm?
20) Lightning over voltage create how much volt?
21) K/s(s+1)(s+5) then find out the value of K so that system become stable.
22) There was a question from definition of Nyquist criteria.
23) Standing done up to the frequency range of? (audio)
24) If a square waveform if given to the supply side of a 2wdg transformer its o/p waveform will be-
25) SC test done on transformer because-
26) If a transformer is operating in .8 PF lag & at efficiency of .9, if now P is .8 lead the efficiency will become.
27) Interpoles are connected for?
28) Dielectric strength of air-
29) A alternator is connected to a grid. Now its prime mover is go slow by ½. Change in its exiting current to held in synchronism.
30) Is the strength of capacitor in LPF is increased the op voltage will-
31) The voltage of a generator and an infinite bus are given 0.92, 10 deg & 1.0, 0 deg resp. the generator acts as a –
32) A wave will not experience any reflection when impedance of line is equal to- surge imp
33) Power transmitted is related to system voltage as-
34) Delay creator ckt name (multivibrator name actually)
35) In tachogenerator adjustment is done by-
36) Surge wave is attended by- (C,L,R)
37) there was 10 question related to measurement-
38) Read all electrostatic instrument related question from any competitive exam book.
39) Lowest reading in moving iron meter is-
40) In galvanometer damping is provided by-
41) In electrodynamic meter a battery & a resistance is provide for-
42) Megger is used for-
43) A question like an ac is applied against a moving coil meter it will reads-
44) Rectifier type instrument measureswhat value - (Rms)
45) Advantage of electrostatic instrument is-
46) Creeping occurs because-
47) Why 2 holes are drilled oppositely in disc of energy meter.
48) Energy meter is a _____ type equipment (recording)
49) There was a question related to selection of a voltmeter based on accuracy-
50) Advantage of hay bridge over anderson bridge-
51) Inductance is measured by – (all the 3 bridge name) .
52) Potentiometer is which type of instrument-
53) Which type of motor is used in refrigerator?
54) Reflection coefficient based problem 1
55) Corona’s advantage-
Technical papers covers 70% frm
Measurement & Instrumentation, Electrical Machine( 90% will be problems) rest frm Power system, power electronics n Control system question type was like this...
1.Find the effective speed of two generator when they operating in parallel with freq. of 50 Hz n 40 Hz? (3600rpm, 500 rpm,3000rpm)
2.question based on deflection torque.
3.Measurent of power by two watt metermethod?
4.Identify type by pu value 0.3,0.3,0.6? (Syn gen., tranmission line, motor)
5.Find the actual reading of voltmeter if error % is given?
6. Pattern in CRO?
7.what to do 4 converting sine wave 2 triangular wave? ( integrating, differntiating, etc)
8.question based on deletion torque of tangent galvenometer?
9.Detection of microwave? (LED, heat, etc)
10.problem based on Sensitivity of bridges, ammeter, voltmeter etc/
11.problem based on rotor resistance n rotor frequency?
12.If a ammeter shows 4A ,suddenlt its downward coil cuts then it will show? ( zero defletion, full sclae, 2A,8A)
13.question based on damping?
14.question on PMMC?
15.loss which wont occur if permamnat magnet is used? options(Hysteriess, eddy curreny, stray,etc)
16.wave shape of aramture mmf? (sine wave, square wave, triangular wave, etc)
17.emf in a conductor is directly proptional to ?( pole-no. of condutor-flux, speed-pole-turns,flux- pole-etc)
18.problem on finding firing angle?
19.whats is the order of jacobian matrix for given no. of bus bar?
20.question based on cyclo converter?
21.queston on measurement of rms?
22.question on electrostatic, electromagnetic, MC, MI instruments?
23.how many watt meter required to measure 3phase 4 wire system? (4,3,2,1)
24.what shud be the range of voltmeter to measure 100v? (100v-1mA,100v-2mA, etc)
25.series n paralell connection of volmeter n ammeter?
26.question on critiacl damping
27.what will be p.f in two watt meter method? (0.5,1,0.8,etc)
28.question on parameter for ABCD line constant
29.triangular spacing of conductors
30.question on hot wire instruments
31.finding full scale deflection
32.question on earthing transformer
33.problem on thermisters
34.problem on syn. gen
35.stability in control system
1) What is the distance between the EHV lines?
a)8m b)11m c)4m d)14m
2) At present how many HVDC lines are there in india?
a)none b)one c)two d)more than two
3) Where is the nuclear located in following places?
ans: i dont remember the answers, but one of them is thalcher(orissa)
4) What is the approximate peak overshoot for a unity feedback system with damping factor 0.6?
a)10% b)5% c)15% d)20%
5) What is the distance between the EHV lines and earth?
a)8m b)11m c)18m d)15m
6) On no load in EHV lines what is the relation between receinving and sending end voltage?
ans: receiving end voltage > sending end voltage
7) What is the surge impedance loading of 400kv line?
ans: 4002/400ohms =400watts
8) similar question with surge impedance given as 160 ohms
ans: 1000watts
9) If both the juctions of transistor are forward biased, in wat region transistor works
ans: saturation region
10) Where is the hydel power plant located in following places?
ans: I dont remember the places
11) self GMD is used in the calculation of_______
a) inductance only
b) inductance and capacitance
c) capacitance only
d) none
12) What is the GMD if the distance between the lines are 6m,6m,12m?
ans: 7.058m( approx)
13) Zero sequence currents doesn't exist in the following fault
a) L-G
b) L-L
c) L-L-G
d) L-L-L-G
Ans: d
14) To avoid arcing connect sutable value of ________ in earthing.
a) capacitance
b) indunctance
c) resistance
d) susceptance
15)There are two to three questions based on Laplace and Inverse Laplace transforms
16)In the following type of conductors the corona is minimum
a) circular
b) stranded
c) helical
d) rectamgular
ans: c
17)When do two wattmeters show same value of opposite readings in two wattmeter method
a) 300 lag
b) 600 lag
c) between 600 and 900 lag
d) zpf lag
ans: d
18) Schering bridge is used to measure
a) frequency
b) inductance
c) capacitance
d) mutual inductance
and: c
19) What is the value of resistance when both length and diameter of the wire are doubled?
ans: halved
20) There is one questions asked on euler's formula..
21) What is the Laplace transform of unit ramp signal?
ans:1/s2
22) What happens to the value of inductance when self GMD is doubled?
23) At what frequency corona loss is more?
a) 50Hz
b) 60Hz
c)
d)
24) What is the largest rating of alternator manufactured in india?
a) 1000MW
b) 500MW
c) 1200MW
d) 250MW
ans:b
25) The response of an RLC circuit for impuse input?
a) exponentially raising
b) sinusoidal
c) exponential falling
d) parabolic
ans: c
26) What is the easier method for finding no. of poles in the right half of s-plane?
a) Niquist plot
b) R-H criterion
c) Root-Locus method
d) Polor plot
ans: b
27) How many no of poles located in the right half of s-plane for the characteristic equation...
28) Burden of current transformers is measured in..
a) Watts
b) Volt Amperes
c) Ampere Hours
d) Joules
29)What is the gate used to get high output when all the inputs are low?
a) NOR
b) NAND
c) Ex-OR
d) Ex-NOR
ans: b
30) Large no of thyristors are used in HVDC transmission to improve______
a) current rating
b) voltage rating
c) Thyristers are available at high ratings
d)
31) What is the line current of a circuit when the current transformer of 1000:5 rating measures 4Amperes?
ans: 800A
32) If the time delay of relay with TMS setting 0.1 is 10 sec, then what is the time delaty when the TMS setting is changed to 0.5
33) How many no of flip-flops are required to get 16 bit counter?
34) _________is connected to reduce frequency errors in ammeter.
a) shunt capacitor
b) series inductance
c) shunt inductance
d)
35)What is the value of ripple factor in Half Wave Rectifier?
a) 1.11
b) 0.8
c) 1.21
d)
36)The principle used in megger?
a) electrostatic effect
b) magnetic effect
c) Induction effect
d)
37)In electrodynamometer type wattmeter the error is due to..
a) pressure coil inductance
b) pressure coil resistance
c)
d)
38) In the following locations where is hydal power plant is not located?
ans: i dont remember the places
39) In distribution lines_____
a) X/R<0.1 b) X/R>10
c) X/R>1
d) X/R<0.01
40) In EHV lines _____
a) X/R=10
b) X/R=100
c)
d)
41) What is the speed of 2 pole alternator at 50Hz frequency?
ans: 3000rpm
42) What is the equivalent decimal no of (624)8
43) What is the binary equivalent of 6.25
44) What is the value of A+AB+B¯ ( B bar)
ans: 1
45) What are the avg and rms values of full wave rectifier
ans: 2Vm/pie, Vm/21/2
46) There is one question based on rank of matrix
47) What is the equivalent of cos(wt+18.750)
a) sin(wt+71.250)
b) sin(wt-71.250)
c) sin(wt+18.250)
d) sin(wt-18.250)
48) The three harmonics will be in phace with each other?_____
a) 3,5,15
b) 2,4,6
c)
d)
ans: a
49) The line current will be equal to phase current in______
ans: delta connection
50) In windmills the frequent problems occur in______
a) mechanical system
b) blades
c) electrodynamic system
d) electric system
51) The machine used in windmills is______
a) alternator
b) induction generator
c)
d)
ans: b
52) Insulators in EHV lines are designed based on_____
a) switching voltages
b) peak voltages
c) corona
d) lightning voltages
ans: a
53) The value of restriking voltage depends on______
a) inductance of line
b) capacitance of line
c) both
d) none
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