1) Which among these is the application of synchronous motor?
i. Ball mills
ii. Metal rolling mills
iii. Crushers
a. i only
b. ii and iii only
c. i and ii only
d. i, ii & iii
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2) Which system present in the synchronous motor makes it costlier than Induction motor of the same size?
a. Damper windings
b. Additional excitation system
c. Additional field windings
d. None of these
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3) What is the usual rating of a synchronous induction motor?
a. Below 25 kW
b. Below 5 kW
c. Above 30 kW
d. Above 100 kW
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4) What is the usual voltage range in the slip rings for the induction motor?
a. 50 V to 115 V
b. 100 V to 1 kV
c. Is proportional to the stator voltages
d. None of these
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5) What is the application of ‘inverse torque power output type’ squirrel cage motor?
a. Conveyors
b. Fans
c. Centrifugal pumps
d. Machine tools
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6) What results if the rotor bar of a squirrel cage rotor is broken?
a. Noise
b. Low starting torque
c. Rated speed is not reached even with rated voltage and frequency
d. All of these
e. None of these
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7) What test is conducted on the synchronous motor before completely assembling the whole machine?
a. Speed torque curves
b. Bearing insulation
c. Dielectric tests on the armature windings
d. Measurement of DC resistance of armature winding
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8) Which method is used to measure the speed of a synchronous machine?
a. Stroboscopic method
b. By tachometer
c. By measuring the frequency by means of frequency meter
d. Only a and b
e. All of these
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9) What is / are the main causes for the noise in the machine?
a. Magnetostriction
b. Aerodynamics
c. Bearing noise of rotating shaft
d. Only b and c
e. All of these
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10) Which among these are the types of single phase AC motors?
i. Induction
ii. Shaded pole
iii. Synchronous
iv. Universal
a. i & ii only
b. ii, iii & iv only
c. i, ii, iii & iv
d. ii & iii only
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11) Which type of rotor is used for single phase induction motor?
a. Wound rotor
b. Squirrel cage rotor
c. Both (A) & (B)
d. None of these
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12) Which method is used for obtaining starting torque in a single phase induction motor?
a. Resistance split phase starting
b. Capacitor start capacitor run
c. Permanent split capacitor motor
d. Only a and c
e. All of these
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13) Which among these DC motor(s) is / are having lower full load torque?
a. Series motor
b. Shunt motor
c. Cumulative motor
d. Differential motor
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14) Which material is used for the manufacture of brushes in DC motors?
a. Graphite
b. Lead
c. Copper
d. All of these
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15) Which among these is the cause of sparking at brushes in DC motor?
a. Defective brushes
b. Defect in Commutator
c. Excessive load
d. Only a and b
e. All of these
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16) Which properties should a material posse so as to be used for electrical equipments?
i. High resistance
ii. High luminosity
iii. Fire retarding insulation
iv. High permittivity
a. i and ii only
b. i and iv only
c. i, iii and iv
d. All of these
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17) For which among these applications is porcelain used?
i. Enclosure for CTs and circuit breakers
ii. Enclosure for large indoor transformers
iii. Enclosure for bushing
iv. Support for bus bars
a. i and ii only
b. ii, iii and iv only
c. i, iii and iv only
d. i, ii, iii and iv
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18) Which material is used as a conducting material in electrical machines?
i. Copper
ii. Aluminium
iii. Nickel
iv. Iron
a. i, iii and iv
b. ii and iv only
c. i and ii only
d. i and iv only
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19) Which among these tests is a DC test?
a. Polarisation index
b. Lightning impulse
c. Induced voltage tests
d. Switching voltage impulse
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20) What is dielectric absorption ratio?
a. (InR 30 s) / (InR 60 s)
b. (InR 60 s) / (InR 30 s)
c. (InR 10 s) / (InR 60 s)
d. (InR 60 s) / (InR 10 s)
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21) What does ‘increasing InR with time indicate’?
a. Healthy insulation
b. Poor insulation
c. Moderate insulation
d. None of these
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22) For what voltage is Twin conductor bundle used in India?
a. 220 kV
b. 500 kV
c. 750 kV
d. 330 kV
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23) Which method of voltage control is applied for long line AC transmissions?
a. Switching by shunt capacitors
b. Tap changing transformers
c. Switching by shunt reactors
d. Static Var sources
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24) At what condition does the corona start, if Es is the electrical stress and Ecr is the critical voltage?
a. Es > Ecr
b. Es = Ecr
c. Es < Ecr
d. Es << Ecr
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25) What will be the span of a transmission line carrying a voltage of 11 kV?
a. 200 m
b. 100 m
c. 260 m
d. 80 m
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26) What should be the permissible sag in meters between two towers if the voltage to be carried is 66 kV?
a. 2 – 4 m
b. 5 – 7 m
c. 4 – 5 m
d. 1.5 m
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27) Which part of the tower is buried in the ground?
a. Anchor
b. Guy wire
c. Braces
d. Strut inclined support
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28) What is / are the types of substations suitable for voltage 66 kV and above?
a. Conventional outdoor
b. SF^ gas insulated metal enclosed substation
c. Hybrid substation
d. Only b and c
e. All of these
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29) What is the range of MHV substations?
a. All voltages above 1000 V AC
b. Voltages between 1kV and 33 kV
c. Between 33 kV and 110 kV
d. 220 kV and 400 kV
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30) At what pressure is the SF6 gas filled in the whole installation of GIS substations?
a. 3 kg / cm2
b. 5 kg / cm2
c. 3 kg / m2
d. 5 kg / m2
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31) Which among these is a type test?
a. Bending test
b. Drainage test
c. Dielectric security test
d. All of these
e. None of these
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32) Which method is used for locating cable fault?
a. Bridge method
b. Tracer method
c. Both bridge and tracer method
d. None of these
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33) What is the expression for the amplitude of the reflected wave?
a. Ir = [ (R + Z) / (R - Z) ] It
b. Ir = [ (R - Z) / Z ] It
c. Ir = [ (R - Z) / (R + Z) ] It
d. Ir = [ (R + Z) / Z ] It
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34) What should be the voltage applied for polymeric cables during partial discharge test?
a. A 15 minute DC test at a voltage 2Vo
b. A 15 minute DC test at a voltage 8Vo
c. A 15 minute DC test at a voltage 4Vo
d. A 15 minute DC test at a voltage Vo
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35) What is the slip equation using stroboscopic method?
a. Slip = (apparent rpm / 120 ) * pair of poles
b. Slip = (apparent rpm / 60 ) * pair of poles
c. Slip = (apparent rpm / 150 ) * pair of poles
d. Slip = (apparent rpm / 30 ) * pair of poles
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