DC Generator Past Paper PDF

DC Generator ( DC Generator ) 1 In DC generator 'X' What is the name of the part marked as ? (a) Amer Core (B) Brush (c) Commutator Razor (d) Commutator Block 2 What is the name of D.C....

DC Generator ( DC Generator ) 1 In DC generator 'X' What is the name of the part marked as ? (a) Amer Core (B) Brush (c) Commutator Razor (d) Commutator Block 2 What is the name of D.C. ? generator? (a) Differential long shunt compound (b) Differential short shunt compound (c) Cumulative long shunt compound (d) Cumulative short shunt compound 3 Which rule is used to find the direction of induced emf in a DC generator? ? (a) Cockettscrew rule (b) Right palm rule (c) Fleshming's left hand rule (d) Fleshming's right hand rule 4 Which formula is used to calculate the emf generated in a DC generator ? (a) Generated emf = ΦZN/60 X A/P VOLT (b) Generated emf = ΦZN/60 X A/P Volt (c) Generated emf = ΦZN/60 X P/A Volt (d) Generated emf = ΦZN/60xΦ X P/A Volt 5 a. What is the formula to calculate the back emf? DC device (a) Eb = Volt (b) Eb = V x Ia Ra Volt (c) Eb = V – Ia Ra Volt (d) Eb = V + Ia Ra Volt 6 What is the name of the part marked 'X' in a DC generator? (a) Pole tip (b) Pole coil (c) Pole core (d) Pole wire 7 What is the name of DC generator? ? (a) Shunt generator (b) Series generator (c) Combination generator (d) Separately excited generator 8 Which energy is converted into electrical energy by a generator? ? (a) thermal (b) dynamic (c) chemical (d) mechanical 9 What is the name of D.C generator field? (a) Short shunt compound generator (b) Long shunt compound generator (c) Differential compound generator (d) Cumulative compound generator 10 What is the principle of DC ? generator (a) Cockett's screw rule (b) Fleschmeng's left hand rule (c) Fleschmeng's right hand rule (d) Faraday's law of electromagnetic induction 11 What is the formula for dynamically induced emf? (A) BLV volts (B) BL sinθ volts (c) BLV sinθ volts (d) BLV cosθ volts 12 Which rule is used to find the direction of the magnetic field? ? (a) Cockett's Screw Rule (b) Right Palm Rule (c) Fleshming's Left Hand Rule (d) Fleshming's Right Hand Rule 13 What is the name of the part of DC generator? (a) Scatter (b) Pole core (c) Pole shoe (d) Yoke or Frame 14 How many parallel paths are there in duplex lap winding of a 4 pole DC generator ? (a) 4 (b) 6 (c) 8 (d) 12 15. Name the parts of DC generator? (a) Side end plates (b) Pole shoe lamination (c) Commutator section (d) Ampere core lamination 16 How are the interpoles connected in a DC generator? (a) In series with the ampere (b) In parallel with the ampere (c) in series with shunt fieldin LA (d) in parallel with the shunt field 17 What is the residual voltage required in a self excitation DC generator ? (a) Build up voltage (b) Reduce the coolant current (c) Reduce the amperage current (d) Maintain constant output voltage 18 In DC machines, what are the two points that measure the brush contact resistance ?े (a) Resistance between opposite brushes (b) Resistance between brush and commutator riser (c) Resistance between brush and commutator (d) Resistance between brush and ampere conductor 19 Which voltage drop is marked as 'X'? (a) Full load voltage drop (b) Amber voltage drop (c) Amber reaction drop (d) Shunt field voltage drop 20 What is the name of compound generator, if the shunt field is connected ुआहैै? in parallel with the ampere (a) Long shunt compound (b) Cumulative compound (c) Differential compound (d) Short Shunt Compound 21 Why is the ampere core of a DC generator welded to (a) reduce copper loss (b) reduce friction loss (c) reduce hysteresis loss (d) reduce eddy current loss 22 Ampere resistance of DC generatorWhy is it less? is multiplied by (a) Reduce ampere current (b) Reduce ampere voltage drop (c) Run ampere with less weight (d) Reduce ampere temperature 23 Why should a D.C. generator be run in clockwise direction only? (a) To avoid damage to the brushes (b) To protect the residual magnetism (c) To avoid short circuit in the ampere (d) To avoid overloading of the generator 24 large DC generators are provided with rotating compensation tanks ? (a) Connect better load (b) Reduce commutation effect (c) Neutralise amperage effect (d) Increase efficiency of generator 25 What is the reason for failure of a DC generator to produce voltage? (a) Loose brush contact (b) Amber resistor is good (c) Field resistor is above critical resistor (d) Prime mover is running above rated speed 26 What is the name of the generator if its field is connected inis it so? parallel with the ampere (a) Shunt generator (b) Series generator (c) Compound generator (d) Self excitation generator 27 What is the purpose of pole shoe in DC generator? (a) reduce the air gap (b) increase the field strength (c) reduce magnetic losses (d) spread the flux evenly in the air gap 28 What is the function of split rings in DC generator? (a) maintains constant voltage (b) collects current in one direction (c) reduces voltage drop across the brush (d) increases terminal voltage as compared to rated voltage 29 Which material is used to make brushes in generator? (a) Steel and graphite (b) Carbonate and graphite (c) Cast iron and graphite (d) Aluminium and graphite 30 Why do DC generators lose their residual magnetism? (a) Heavy short circuit under load (b) Continuous running without load (c) Continuous running without brake (d) Direction of rotation changes frequently 31 How is the magnetic circuit in a generator completed through yoke and poles (a) Field coils (b) Ampere core (c) Turned pole core (d) Winding conductors in ampere 32 Why does the terminal voltage decrease when load increases in a DC shunt generator? (a) Due to ampere feedback effect (b) Due to increase in ampere resistors (c) Due to brush voltage decreases the drop (d) Due to increase in shunt field inductance 33 Which type of DC generator is used for long distance distribution lines (a) Shunt generator (b) Series generator (c) Differential compound generator (d) Additive compound generator 34 Which method is used to improve the insulation resistance in a DC generator (a) Changing the brushes frequently (b) Warming the machine from time to time (c) Cleaning the commutator segments regularly (d) Airing the machine during maintenance 35 How does a D.C. generator work in the absence of residual magnetism? (a) Shunt generator (b) Series generator (c) Combination generator (d) Separately excited generator 36. Which type of DC generator is used for arc welding? (a) Shunt generator (b) Series generator (c) Differential compound generator (d) Additive compound generator 37 What is the speciality of wave winding in D.C generator? (a) Low voltage (b) High voltage (b) Low voltage (C) Low to high voltage (D) High to high voltage 38 What is the purpose of resistor used in commutator connection in? DC generator (a) Maintain constant voltage (b) Zero statically induced emf (c) Increasing statically induced emf (d) Smoothly reversal of current direction 39 Why are solid poles used in D.C.? (a) To reduce copper losses (b) To increase residual magnetism (c) To reduce residual magnetism (d) To reduce the reluctance of the magnetic path 40 Which metal is used for making yoke of large capacity DC generator (a) Cast iron (b) Malleable iron (c) Aluminium (d) Rolled steel 41 What is the function of split rings in a D.C. generator? (a) Supply continuous output (b) Produce output in one direction (c) Produce output in opposite direction (d) Collect output from alternating conductor 42 Which type of voltage is dynamically induced in a DC generator? ? (a) Pulsating voltage (b) Fluctuating voltage (c) Alternating voltage (d) Direct current voltage 43 What is the purpose of the slot marked 'X'? (a) To adjust the key method (b) To create air circulation (c) For cleaning purpose (d) For easy removal from the shaft 44 What is the purpose of field coil in D.C. generator? (a) To increase the flux in the air gap (b) To decrease the magnetic flux (c) To magnetise the poles to produce helical flux (d) To increase the reluctance of the magnetic path 45. Which metal is used to make pole cores of large DC generator machines?? (a) Malleable iron (b) Cast iron (c) Cast steel (d) Stainless steel 46 Why pole cores are used in stripping DC generators to ? (a) Reduce rotation loss (b) Reduce winding loss (c) Reduce diaphragm loss (d) Reduce eddy current loss 47 Which type of DC generator is used for electroplating process? (a) Shunt generator (b) Series generator (c) Differential compound generator (d) Additive compound generator 48 What is the purpose of compensating winding in a DC generator? (a) Reduces harsh commutation (b) Maintains constant output voltage (c) Reduces magnetic effect (d) Reduces excitation force of field coils 49 If the shunt field is above the resonant value then what is the effect? ​D.C Generator? (The ) output voltage is pulsating (BOutput ) voltage is above normal (The ) rectifier fails to produce voltage (The ) degenerator normally produces voltage What is the effect of ampere reaction in generator? 50 D.C. (The ) output voltage increases (bOutput ) voltage decreases (Coutput ) voltage is fluctuating (The ) output voltage will drop to zero 51 A 4 pole DC generator with complex wave wound amperes has 1020 conductors and a speed of 1500 rpm If the speed of the magnet is 0.007, the flux/pole is 0.007 weber; calculate the emf produced? (A) 178 V (B ) 243 V (C ) 357 V (D ) 428 V 52 How can the effect of ampere feedback be neutralised in a large DC generator? (Using ) Compensated Winding (B.)Providing additional interpoles (Increasing ) Seabrush Contact Resistance (Connecting ) reverse wires with dividing 53 D.C What effect does the generator , have if it is kept closed for a long time? (A.) The field coil pressure increases (B )increases the amperage (C. Increase ) the response of the amendment (D )is a requirement for reliability 54. 4 Calculate the induced emf of the pole dynamo, 1000 rpm lap wound and total number of conductors 600 hayfluxpol , / 0.064 wb ?is ()A160 V (B ) 320 V (C ) 480 V (D ) 640 V 55 If the main field flow is radiated into a DC generator, what will be the effect on the induced emf? (A)induced emf increases (B decreases ) the induced emf (C )No change in induced emf ं (The ) induced emf becomes zero 56 What is the reason for heavy packing in the brush of DC generator? (Short ) circuit in A field winding (Shortcuts ) in B Amey Rewinding (CMNA&GNAHsituation ) changed (Very good spring tension as D brush ) Answers: 1-C|2-A|3-D|4-C|5-C|6-D|7-D|8- D | 10 - D | 11 - C | 12 - D | 13 - D | 14 - C | 15 - D | 16 - A | 17 - A | 18 - C | 19 - C | 20 - D | 21 - D | 22 - B | 23 - B | 24 - C | 25 - C | 26 - A | 27 - D | 28 - B | 29 - B | 30 - D | 31 - B | 32 - A | 33 - D | 34 - D | 35 - D | 36 - C | 37 - C | 38 - D | 39 - D | 40 - D | 41 - B | 42 - C | 43 - A | 44 - C | 45 - C | 46 - D | 47 - A | 48 - C | 49 - C | 50 - B | 51 - C | 52 - A | 53 - D | 54 - D | 55 - B | 56 - C | Q57. A generator is used as a booster in the Railway Distributor System a shunt generator b c CompounderGenerator None of the above d Q58. GNA The full name of is a Geomede rcal neur l ehxs gracfclneurl ehxs b c GeneratorNeuralAxes None of the above d Q59. cry material D.C. Generators are used in generating stations a Paper b wood c Fiber Mica d Q60. D O C O What are the applications of shunt generator a Welding Generator Set Booster b c electroplating electrical d equipment Q61. The O decomposition O of the generator can be reduced to a To get the company to conduct the tangwinding operation in the main pollface fro b GNA m ME to transfer the status of the case c What is the use of a common brush to provide the interpole to the main pole? d Q62. D O C O This is the main reason why the voltage in the generator is not rated a Generator , is rated speed b The regional circuit , is better than the regional tax collectors c The residual impurities in the area are in the proper contact d with the brush Q 63. Terminalे voltage in a single-circuit 400 Voltage is , Field Shunt 80 it is | Restart onam compound Calculation generator of shunt field current a 3.2 amp b 4.0 amp c 5.0 amp d 5.5 amp Q 64. generatorhsmeshunfield े , The series field is connected after the a DCO Series O Laser Rater b DCOShunt O Gen Ratio c D O C O short shunt compound generator long shunt d DO C O compound generator Q65. What is the number of parallel paths of the connected wave winding in a DC generator? a6b 4c2 d Q66. In the rule of the right hand of flashiming, the front finger indicates a िुम्बकीयप्रवाहकीदिशा b e.m.f. inspired direction of c Direction of motion of the conductor d Direction of development of Motivational Q67. D O C O What is the utility of brush in generator toA theC O Convert to unidirectional current b collect current from commutator c Connect the amplifier and commutator to increase your d workflow Q68. According to Bureau of Indian Standards, DCGs are a separate entity, his shunt The winding mechanism will be marked as field a D1 & D2 b B1 & B2 c F1 & F2 d E1 & E2 Q69. डीoSimplex O lap wound ampere in 6 - How many parallel paths segenerator are there in a mole a4b6c 8 d 12 Q70. How O can O the Ross-magnetizing effect of ampere reaction be eliminated in a degenerator? a By providing the difference pole of the principal pole by inserting a rotational b compensator  fro by transferring the position of the brush c GNA m I, d eHampire - tonnage , area increases in winding Q71. compounddc O O One use of a generator is a For railways For welding gen raters b For electroplating d Q72. Single long shut off compound generator at 400 volts 100 load current of the , Shunten Pranaro ampere reaches Field 200 what will ,be the onmahaiyamer current a 100 A b 102 A c4Ad2 A Q73. D O C O What are the main conditions for parallel to the generator? a Capacity of both generators should be same. Field current should be uniform across. b c The polarity of both the generators should be same. The maximum capacity of both the generators should be same. d Q74. Which - of the following is one of the reasons for loss of residual capacity of an active DC generator? a America is not responding properly b The generator has been idle for a long time c amr response 1 is better than onm wrong brush position d Q75. Which of these devices is an over compound DC generator? a Electroplating Railways b c Wehldung generator lathes d 57.a 58.a 59.d 60.c 61.c 62.b 63.c 64.d 65.c 66.a 67.b 68.d 69.b 70.c 71.a 72.b 73.c 74.b 75.b