Assessment G.v.K Ashish Kumar

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<p>ASHISH KUMAR SHARMA</p> <p>Assessment will be over in/w EPDw ULLTE3N</p> <p>50:00 minutes</p> <p>Important instructions &amp; Guidelines Technical Questions: 50, 1 mark for correct answer, no negative markingA synchronous motor</p> <p>Q 1. A synchronous condenser is the same as Option A B C D</p> <p>An induction motor used to improve power factor DC motor being run as an alternator</p> <p>None of the above Q 2. The eddy current loss in an ac electric motor is 100W at 50Hz. Its loss at 100Hz will be Option A 25 W B 59 W C 100 W D 400 W Q 3. Silicon Steel is preferred for transformer core because Option A It decreases the permeability of the core B It reduces the both eddy current loss and hysteresis loss C It reduces receptibility of the core D It decreases the tensile strength Q 4. The voltage of a particular bus can be controlled by controlling the Option A Phase Angle B Reactive power of the bus C Active power of the bus D Phase angle &amp; reactive power Q The synchronous speed for a 6-pole induction motor is 1200rpm. If the number of poles is now 5. reduced to 4 with the frequency remaining constant, the rotor speed with a slip of 5% will be______. Option A 1690 rpm B 1750 rpm C 1500 rpm D 1710 rpm Q 6. Power factor of a circuit can be defined as Option A True power/apparent power B Resistance/impedence C Cosine of angle between voltage and current</p> <p>D Q 7. The electrolyte in a lead-acid cell contains Option A B C D Q 8. Energy stored in capacitor is Option A B C D</p> <p>All the above H20+H2SO4 H2O+ HCI H2O+HNO3 Distilled water CV2 C2 v2 CV2 C2 v 2</p> <p>Q 9. The transformers are rated in KV instead of kW because Option A Load power factor is often not known B KV is fixed whereas KW depends on load PF C KV is fixed whereas KW depends on load PF D Because it is customary Q 10. Which one of the following material is having highest dielectric constant Option A Air B Mica C Parafin D Dry Paper Q 11. Which one of the following supervision function is not part of the generator monitoring? Option A Temperature monitoring B Buchholz protection C Vibration monitoring D Casing expansion Q 12. Increased rotor resistance in rotor circuit of induction motor is to achieve Option A High starting torque B More Speed variation C Low Starting Torque D None Q 13. On load tap changer is normally used in Option A HV side of the transformer B LV Side of the transformer C Either of the above</p> <p>None of the above Generator capability curve is used to determine A The active power capability of the machine B The reactive power capability of the machine C The MVA capability of the machine D The limiting parameters for operation of the machine Q 15. The capital cost is more with Option A Thermal power plant B Hydro Power plant C diesel power plant D gas based power plant Q 16. In a star connected 3 Phase Load Power is equal to 1.732*V*I*Cos Phi. Then Option A V is line Voltage &amp; I is Line Current B V is line Voltage &amp; I is Phase Current C V is Phase Voltage &amp; I is Phase Current D V is Phase Voltage &amp; I is Line Current Q 17. In UHV circuits which is more important when designing the surge protection Option A Switching B Lightning C Cant say D None Q 18. The positive sequence component of voltage at the point of fault is zero when it is Option A 3 phase fault B L-L fault C L-L-G fault D L- G fault Q 19. The power consumption, in case of centrifugal loads (like pump, fan etc), proportional to Option A Speed B Square of speed C cube of speed D Not applicable Q In a circuit a single resistor is connected across D.C. source, what will be the effect on current in 20. first resistor if we connect one more same rated resistance in parallel with earlier one Option A No Change B Will be Half Q 14. Option</p> <p>D</p> <p>C D</p> <p>Will be doubled</p> <p>None Q 21. The size of a conductor used in power cables depends on the Option A operating voltage B current to be carried C power factor D type of insulation used Q 22. Which statement is true? OptionA A circuit breaker can be switched on and off under load B A disconnecting switch can be switched on and off under loadb) A disconnecting switch can be switched on and off under load C A disconnecting switch only can disconnect under load Q 23. Reactance relay is normally preferred for protection against Option A Earth Fault only B Phase Fault only C Both of the above D None of the above Q 24. In a power Transformer Option A Primary winding is closer to core B Secondary winding is closer to core C LV winding is closer to core D HV winding is closer to core Q 25. Pick the bad conductor of electricity Option A Copper B Aluminium C Tungsten D Porcelain Q 26. 13. Does a DC motor work as Generator Option A Yes B No C Cant Say Q 27. In mechanical analogy which one is equal to Inertia Option A Resistance B Inductance C Capacitance</p> <p>B&amp;C Q 28. Capacitors with automatic power factor controller when installed in plant Option A Reduces active power drawn from grid B Reduces the reactive power drawn from the grid C Reduces the voltage of the plant D Increases the load current of the plant Q 29. What are the conditions required to synchronise a generator to an infinite grid Option A Equality of voltage B Equality of frequency C Synchronism of phases D All the above Q 30. A motor which can be conveniently be operated at lagging as well as leading power factors is the Option A Squirrel cage induction motor B Wound rotor induction motor C Synchronous motor D DC shunt motor Q 31. In a network to neglect a voltage source, the terminals across the source are Option A Open-circuited B Short-circuited C Replaced by some resistance D replaced by inductor Q 32. The capacity of the battery system can be specified in Option A Ampere hours B Watt Hours C Joules D Volt amps Q 33. Carrier current protection scheme is normally used for Option A HV cables only B HV transmission lines only C Both of the above D None of the above Q The primary winding of a 220/6V, 50Hz transformer is energized from 110V, 60Hz supply. The 34. secondary output voltage will be Option A 2.5 V B 3.0 V</p> <p>D</p> <p>C D Q 35. Option A B C D The sheath is used in cable to Provide strength to the cable Provide proper insulation</p> <p>3.6 V 6.0 V</p> <p>Prevent the moisture from entering the cable</p> <p>Avoid chances of rust on strands Q 36. The motor used for traction application Option A Series motor B Shunt motor C Slip ring motors D Any of the above Q 37. Ideal voltage source have Option A Zero internal resistance B Infinite internal resistance C Low value of current D Large value of emf Q 38. Electrical transformer works on the principle of Option A Mutual Induction B Self induction C Both D Flemings Law Q A transformer operates most efficiently at 3/4th full load. Its iron (PI) and copper loss (PCu) at full 39. load are related as: Option A PI/PCu = 16/9 B PI/PCu = 4/3 C PI/PCu = 3/4 D PI/PCu = 9/16 Q 40. Differential protection of generator works on the principle of Option A Current imbalance B Voltage Imbalance C Power imbalance D None Q 41. What is braking the turbine under load conditions? Option A The load angle</p> <p>B C</p> <p>The power factor</p> <p>The active power of the generator Q The inexpensive way to improving energy efficiency of a motor which operates consistently at 42. below 40% of rated capacity is by Option A Operating in Star mode B Replacing with correct sized motor C Operating in delta mode D None Q 43. Reduction in supply voltage by 10% will change the torque of the motor by Option A 38% B 19% C 9.5% D No change Q 44. The excitation system controls ______________ before synchronizing? Option A The speed of the turbine B The frequency C The generator voltage Q An alternator is delivering rated current at rated voltage and 0.8 power factor lagging. If it is 45. required to deliver rated current at rated voltage and 0.8 power factor leading, the required excitation will be Option A Less B More C More or less D The same Q 46. Which one of the following is applied for a motor Option A Flemings Left Hand Rule B Flemings Right Hand Rule C A&amp;B D None Q 47. Which is the unit of magnetic flux density Option A Gauss B Maxwell C Permeability D Ampere Turn Q 48. The current from the stator of alternator is taken out to the external load circuit through Option A slip rings</p> <p>B C D</p> <p>commutator segments solid connections</p> <p>carbon brushes Q Tendency of alternating current (AC) to flow mostly near the outer surface of a solid electrical 49. conductor is called Option A Skin effect B Hall effect C Ferranti Effect D A&amp;C Q A 1:5 step-up transformer has 120V across the primary and 600 ? resistance across the secondary. 50. Assuming 100% efficiency, the primary current equals Option A 0.2 A B 5A C 10 A D 20 A Total Questions :50 Answered :50 Unanswered :0 Are you sure you want to submit??</p> <p>Submitted.</p> <p>Logout</p> <p>Question NumberAbout Us | Contact Us</p> <p>CoCubes Id: Questions: Attempted:</p> <p>Your Answer</p> <p>Copyrights 2010-11 VIA Human Resource Solution Pvt. Ltd.</p>