1) Which among these systems is an auxiliary plant in a power system?
a. Fuel oil system
b. Raw water system
c. Transformer oil plant
d. All of these
e. None of these
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2) Which among these require a low voltage DC source?
a. Telemetering and communication
b. Uninterrupted power supply
c. The protective relays and the trip circuit
d. All of these
e. None of these
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3) Which circuit among the following requires a supply of 48 V DC source?
a. Trip coils and closing coils
b. Micro wave protection and communication
c. Dc measuring instruments
d. All of these
e. None of these
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4) How is an electrochemical cell rated if ‘n’ cells are connected in series?
a. Ah (ampere hour)
b. n Ah
c. Ah / n
d. nV / Ah
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5) A primary cell is chemically _____________________.
a. Irreversible
b. `Reversible
c. Reversible only once
d. Reversible upto five times
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6) Which element is used as an anode in a dry cell?
a. Carbon
b. Zinc
c. Lead
d. Zinc sulphate
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7) Which gel ensures the dryness of the incoming air in the breather?
a. Potassium gel
b. Silica gel
c. Carbon gel
d. All of these
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8) Which cooling system is employed for large transformers?
a. Oil natural oil forced
b. Oil natural air forced
c. Oil forced air forced
d. Both (b) and (c)
e. All of these
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9) Which among the following safety devices are provided on the power transformers?
a. Marshalling kiosk
b. Vacuum gauge
c. Pressure relief gauge
d. All of these
e. None of these
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10) What is the use of current transformers?
a. Stepping up AC current
b. Measuring and protection
c. Stepping down AC current
d. Both (b) and (c)
e. All of these
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11) What is rated burden in current transformers?
a. The specified limits of ratio error and phase angle error.
b. The ratio of rated short time current to rated primary current.
c. A specification by the manufacturer at which CT performs with the specified accuracy.
d. The phase angle between primary current vector and reversed secondary current vector.
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Answer
Explanation
Related Ques
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ANSWER: A specification by the manufacturer at which CT performs with the specified accuracy.
Explanation:
No explanation is available for this question!
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12) What is over current factor?
a. The specified limits of ratio error and phase angle error.
b. The ratio of rated short time current to rated primary current.
c. A specification by the manufacturer at which CT performs with the specified accuracy.
d. The phase angle between primary current vector and reversed secondary current vector.
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Answer
Explanation
Related Ques
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ANSWER: The ratio of rated short time current to rated primary current.
Explanation:
No explanation is available for this question!
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13) What is the pressure of SF6 gas in a single pressure puffer type SF6 circuit breaker?
a. 2 – 4 kg / cm2
b. 4 – 6 kg / cm2
c. 6 – 8 kg / cm2
d. 8 – 10 kg / cm2
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14) What is the minimum deionisation time necessary for auto reclosing in a circuit breaker if the voltage of transmission line is 132 kV?
a. 5 cycles
b. 14 cycles
c. 9 cycles
d. 13 cycles
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15) Which among the following device is connected to provide protection against phase to earth insulation failure?
a. Earth fault relay connected in neutral to earth circuit.
b. Earth fault relay connected in three phase residual secondary circuit of C T secondaries
c. Differential protection
d. All of these
e. None of these
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16) What is the function of control cables?
a. For protective circuits between C Ts, V Ts, and relays
b. To sense the fault and close trip circuit for circuit breaker
c. Opening and fault clearing
d. All of these
e. None of these
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Answer
Explanation
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ANSWER: For protective circuits between C Ts, V Ts, and relays
Explanation:
No explanation is available for this question!
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17) Which among these tests are performed periodically?
a. Repair tests
b. Maintenance testing
c. Manufacturers tests
d. All of these
e. None of these
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18) Which among these gases is not used as a coolant?
a. Hydrogen
b. Nitrogen
c. Carbon dioxide
d. Helium
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19) Which enclosures are preferred for preventing entry of falling water or dirt?
a. Totally enclosed
b. Drip splash or hose proof
c. Open end bracket
d. All of these
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20) What does IC 01 describe?
a. Self cooled open machine fan mounted on the shaft
b. Totally enclosed machine frame cooled no extra fan
c. Totally enclosed machines frame and tubes externally and internal fault.
d. Inlet pipe self ventilated machines fan mounted on the shaft.
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Answer
Explanation
Related Ques
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ANSWER: Self cooled open machine fan mounted on the shaft
Explanation:
No explanation is available for this question!
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21) What is the maximum permissible voltage drop that can be sustained while starting an electrical rotating machine?
a. 15 – 20 % of the rated voltage
b. 20 – 25 % of the rated voltage
c. 5 – 10 % of the rated voltage
d. 0 – 5 % of the rated voltage
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22) On what factors is the rated voltage selected for an induction motor?
a. Motor rating
b. Starting current
c. Fault levels of supply
d. All of these
e. None of these
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23) Which relation governs the fault level of the supply in LV motors?
If K – factor for number of motors started simultaneously started on the same bus
Sa – 3 phase fault level
M – Rated MW of any one motor
a. Sa = K * 50 * M
b. Sa = K * 20 * M
c. Sa = K * 60 * M
d. Sa = K * 80 * M
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24) On what factors does the size of the induction motor depend?
a. Power output
b. Frequency
c. Speed of rotation
d. Both (A) and (C)
e. All of these
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25) On what type of bearing does the heavy power electrical machine rotate?
a. Ball bearing
b. Sleeve bearing
c. Roller bearing
d. Any of these
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26) What is the temperature limit for the storage of machines at site before installation?
a. Temperature above + 25 °C
b. Temperature above + 5 °C
c. Temperature less than 10 °C
d. Temperature above 15 °C
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27) What is the main cause of harmful vibrations in the machine?
a. Mechanically unbalanced rotor
b. Bent or cracked shaft
c. An excessively pulsating load
d. All of these
e. None of these
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28) Which types of bearings are used for fractional HP motors?
i. Sleeve bearing
ii. Ball bearing
iii. Roller bearing
iv. Needle bearing
a. i & ii only
b. ii & iii only
c. iii & iv only
d. i, ii, iii & iv
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29) What is / are the functions of sealing device used along with bearings?
a. To prevent leakage of oil from the bearing housing
b. To prevent dust, water, dirt etc from entering the bearing housing
c. Both (a) and (b)
d. None of these
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30) What is the maximum rated output for an engine driven synchronous generator?
a. 10 MW
b. 20 MW
c. 50 MW
d. 100 MW
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31) Which type of cooling system is preferred for turbo alternators?
a. Forced air
b. Hydrogen
c. Water cooled
d. Only (b) & (c)
e. All of these
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32) Which type of rotor is used by Hydro Generators?
a. Salient pole
b. Cylindrical rotor
c. Both (A) and (B)
d. None of these
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33) Which type of rotor is designed for synchronous motor rating upto 5 kW?
a. Squirrel cage rotor
b. Slip ring rotor
c. Salient pole rotor
d. Cylindrical rotor
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34) What is / are the different type(s) of excitation system of a synchronous motor?
a. Slip ring type
b. Brushless type
c. Both (A) and (B)
d. None of these
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35) At which power angle is the pull out torque developed in the synchronous motor?
a. δ = 45 °
b. δ = 30 °
c. δ = 70 °
d. δ = 90 °
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