178 + Interview Questions in Design Of Synchronous Machines in Design Of Electrical Machines Page 3 InterviewSolution

101.	What is the relation between coil span and harmonics?(a) low coil span decreases harmonics to less amount(b) low coil span decreases the harmonics drastically(c) high coil span decreases the harmonics drastically(d) high coil span decreases the harmonics by small amountI got this question during an interview.Question is from Armature Design in division Design of Synchronous Machines of Design of Electrical Machines
Answer» The correct CHOICE is (b) low coil SPAN decreases the HARMONICS drastically Easiest explanation: The coil span is KEPT low in order to decreases the harmonics. The advantage of having lower coil spans is that it reduces the harmonics drastically.

Discussion

102.	Fractional windings are invariably used in synchronous machines.(a) true(b) falseThe question was asked in exam.Question is taken from Armature Design topic in section Design of Synchronous Machines of Design of Electrical Machines
Answer» Correct ANSWER is (a) true The explanation: Fractional slot windings REDUCES the distribution factor for higher harmonics thus reducing their CORRESPONDING generated EMFS and making the voltage NEARLY sinusoidally. Fractional slot windings are invariably used in synchronous machines.

Discussion

103.	When is the range of the number of slots per pole per phase in the salient pole machines?(a) 2-3(b) 3-4(c) 2-4(d) 2-6The question was posed to me in final exam.My question is based upon Armature Design topic in chapter Design of Synchronous Machines of Design of Electrical Machines
Answer» Correct choice is (C) 2-4 Explanation: The minimum VALUE of the number of slots per pole per PHASE is 2. The maximum value of the number of slots per pole per phase is 4.

Discussion

104.	What is the range for the stator slot pitch for the large hydro-electric generators?(a) 50-60 mm(b) 50-70 mm(c) 50-80 mm(d) 50-90 mmI had been asked this question in my homework.I need to ask this question from Armature Design topic in division Design of Synchronous Machines of Design of Electrical Machines
Answer» The correct choice is (d) 50-90 MM The explanation is: The minimum VALUE for the stator slot pitch for the large hydro-electric generators is 50 mm. The maximum value for the stator slot pitch for the large hydro-electric generators is 90 mm.

Discussion

105.	What is the value of the slot pitch for the low voltage machines?(a) slot pitch < 25 mm(b) slot pitch = 25 mm(c) slot pitch less than equal to 25 mm(d) slot pitch greater than equal to 25 mmThe question was posed to me during an online interview.Query is from Armature Design topic in division Design of Synchronous Machines of Design of Electrical Machines
Answer» The correct option is (c) slot PITCH LESS than equal to 25 mm To explain: The value of the slot pitch DEPENDS upon the voltage of the MACHINE. The slot pitch is less than equal to 25 mm for LOW voltage machines.

Discussion

106.	How is the number of armature slots associated with the flux densities in iron?(a) tooth ripples are increased, if the number of slots are increased(b) tooth ripples are decreased, if the number of slots are increased(c) tooth ripples are increased, if the number of slots are decreased(d) tooth ripples are decreased, if the number of slots are decreasedI had been asked this question in an international level competition.My enquiry is from Armature Design topic in division Design of Synchronous Machines of Design of Electrical Machines
Answer» Right choice is (a) tooth RIPPLES are INCREASED, if the number of slots are increased To explain: The LARGE number of slots a greater space is taken up by the insulation. This RESULTS in the NARROWER teeth giving flux densities which may go beyond acceptable limits.

Discussion

107.	The value of slot pitch depends upon the voltage of the machine.(a) true(b) falseThe question was asked by my college director while I was bunking the class.My enquiry is from Armature Design in division Design of Synchronous Machines of Design of Electrical Machines
Answer» The correct option is (a) true For explanation I would SAY: The VALUE of the SLOT pitch SERVES as a guide when choosing the number of armature slots. The value of the slot pitch depends upon the voltage of the machine.

Discussion

108.	How is the number of armature slots associated with the tooth ripples?(a) tooth ripples are increased, if the number of slots are increased(b) tooth ripples are decreased, if the number of slots are increased(c) tooth ripples are increased, if the number of slots are decreased(d) tooth ripples are decreased, if the number of slots are decreasedI had been asked this question during a job interview.My enquiry is from Armature Design topic in chapter Design of Synchronous Machines of Design of Electrical Machines
Answer»

Discussion

109.	How is the number of armature slots associated with the leakage reactance?(a) small number of slots leads to less leakage reactance(b) small number of slots leads to high leakage reactance(c) large number of slots leads to high leakage reactance(d) large number of slots leads to low leakage reactanceI have been asked this question during an online exam.Asked question is from Armature Design topic in chapter Design of Synchronous Machines of Design of Electrical Machines
Answer» Right ANSWER is (a) small number of slots leads to less LEAKAGE reactance For explanation I would say: When the number of slots is small the leakage FLUX is increased. As the leakage flux is increased, the leakage reactance is increased OWING to conductors LYING near each other.

Discussion

110.	How is the number of armature slots associated with the cost factor?(a) small number of slots leads to less cost(b) small number of slots leads to high cost(c) large number of slots leads to high cost(d) large number of slots leads to low costI have been asked this question during an interview for a job.This intriguing question originated from Armature Design topic in division Design of Synchronous Machines of Design of Electrical Machines
Answer» Right option is (a) small NUMBER of slots leads to less cost The best explanation: The smaller the number of slots, the less will be the cost. This is because there are FEWER coils to WIND, FORM insulate, PLACE into slots, and connect.

Discussion

111.	How is the number of armature slots associated with the hotspot temperature?(a) small number of slots leads to less hotspot temperature(b) small number of slots leads to high hotspot temperature(c) large number of slots leads to high hotspot temperature(d) large number of slots leads to low hotspot temperatureI had been asked this question in an interview for internship.I want to ask this question from Armature Design topic in section Design of Synchronous Machines of Design of Electrical Machines
Answer» Correct answer is (b) small number of slots leads to high hotspot TEMPERATURE The explanation is: The small number of slots leads to an INCREASE in hotspot temperature. The small number of slots RESULTS in BUNCHING of conductors leaving small space for circulation of AIR.

Discussion

112.	The single layer windings have higher efficiency and quieter operation because of narrow slot openings.(a) true(b) falseI have been asked this question in an internship interview.The doubt is from Armature Design topic in division Design of Synchronous Machines of Design of Electrical Machines
Answer» The correct choice is (a) true Easiest explanation: The single layer WINDING has high efficiency and quiet operation because of narrow slot openings. They also have higher space factor owing to the absence of INTER layer separator.

Discussion

113.	How is the number of armature slots associated with the armature windings?(a) number of slots should be such that unbalanced winding is obtained(b) number of slots should be such that balanced winding is obtained(c) number of slots should be so low as possible(d) number of slots should be high as possibleI had been asked this question in an internship interview.My doubt stems from Armature Design in portion Design of Synchronous Machines of Design of Electrical Machines
Answer» The correct OPTION is (b) number of SLOTS should be such that balanced winding is obtained The best I can explain: The number of slots should be such that balanced winding is obtained. Balanced windings should be obtained because it may lead to LOSSES and HEATING effects.

Discussion

114.	How many factors are related in the selection of the armature slots?(a) 5(b) 6(c) 7(d) 4I have been asked this question in an interview for job.My doubt is from Armature Design topic in chapter Design of Synchronous Machines of Design of Electrical Machines
Answer» Right ANSWER is (b) 6 The explanation is: There are 6 factors associated with the selection of the armature slots. They are i) Balanced windingsii) Costiii) Hot spot temperatureiv) LEAKAGE reactancev) Tooth RIPPLES vi) FLUX density in iron.

Discussion

115.	When is the double layer bar or wave windings made use of?(a) when single turns coils are necessary as with turbo alternators and unipolar low voltage machines(b) when single turns coils are necessary as with turbo alternators and bipolar low voltage machines(c) when single turns coils are necessary as with turbo alternators and multipolar low voltage machines(d) when double turns coils are necessary as with turbo alternators and unipolar low voltage machinesThe question was posed to me in an online interview.Origin of the question is Armature Design in chapter Design of Synchronous Machines of Design of Electrical Machines
Answer» Right answer is (c) when single turns coils are necessary as with turbo ALTERNATORS and multipolar LOW voltage machines The EXPLANATION is: The double layer BAR or wave windings are used when the single turns coils are necessary. They are also made use of with the multipolar low voltage machines.

Discussion

116.	Which among the following makes double layer windings advantageous than the single layer windings?(a) ease in the manufacture of coils and lower cost of winding(b) less number of coils are required as spare in the case of winding repairs(c) fractional slot windings can be employed(d) ease in the manufacture of coils and lower cost of winding, fractional slot windings can be employed, less number of coils are required as spare in the case of winding repairsI have been asked this question in final exam.The above asked question is from Armature Design topic in chapter Design of Synchronous Machines of Design of Electrical Machines
Answer» Correct answer is (d) EASE in the manufacture of coils and lower cost of winding, fractional slot WINDINGS can be employed, less number of coils are required as spare in the case of winding repairs The explanation is: The DOUBLE LAYER windings have an advantage over single layer windings because of ease in the manufacture of coils and lower cost of winding, less number of coils are required as spare in the case of winding repairs, fractional slot windings can be employed.

Discussion

117.	Which type of machines have a large number of poles per phase?(a) high voltage machines and machines with high value of flux per pole(b) high voltage machines and machines with small value of flux per pole(c) small voltage machines and machines with high value of flux per pole(d) small voltage machines and machines with low value of flux per poleI got this question by my college director while I was bunking the class.My question is taken from Armature Design topic in portion Design of Synchronous Machines of Design of Electrical Machines
Answer» Correct CHOICE is (b) high voltage machines and machines with SMALL value of FLUX per pole Easiest explanation: The high voltage machines have a LARGE number of poles per phase. The small value of flux per pole per phase also results in large number of poles per phase.

Discussion

118.	How many factors does the design of armature of synchronous machines depend upon?(a) 2(b) 4(c) 3(d) 5I got this question at a job interview.This question is from Armature Design topic in portion Design of Synchronous Machines of Design of Electrical Machines
Answer» The correct choice is (d) 5 Explanation: There are 5 factors that decide the design of the armature of synchronous MACHINES. They are i) SINGLE or double layer winding, ii) NUMBER of armature SLOTS, iii) coil span, iv) turns per PHASE, v) conductor section.

Discussion

119.	When are the double layer bar windings made use of during the armature design?(a) large values of flux per pole and small number of turns per phase(b) large values of flux per pole and large number of turns per phase(c) small values of flux per pole and small number of turns per phase(d) small values of flux per pole and large number of turns per phaseI had been asked this question during an interview for a job.I'm obligated to ask this question of Armature Design in section Design of Synchronous Machines of Design of Electrical Machines
Answer» Correct choice is (a) LARGE values of flux per POLE and SMALL number of turns per phase Easy explanation: The double layer BAR windings are made USE of when there is large values of flux per poles. The double layer bar windings are made use of when there are small number of turns per phase.

Discussion

120.	What is the mechanical strength of the end bells used?(a) 1120 MN per m^2(b) 1130 MN per m^2(c) 1150 MN per m^2(d) 1140 MN per m^2The question was posed to me in an online quiz.This intriguing question originated from Construction of Turbo-Alternators topic in division Design of Synchronous Machines of Design of Electrical Machines
Answer» CORRECT answer is (C) 1150 MN per m^2 Easiest explanation: The end BELLS are made of a non-magnetic austenitic steel in ORDER to reduce the leakage FLUX. The end bells have high mechanical strength of about 1150 MN per m^2.

Discussion

121.	The rotor is slotted for one-third of its periphery.(a) true(b) falseThe question was asked in an interview for internship.Question is taken from Construction of Turbo-Alternators topic in division Design of Synchronous Machines of Design of Electrical Machines
Answer» RIGHT CHOICE is (b) false The best EXPLANATION: The ROTOR is slotted for only two-thirds of its periphery. It is because to reduce the flux pulsations and the cost FACTORS.

Discussion

122.	How many types are the rotor slots distinguished into?(a) 2(b) 3(c) 4(d) 5The question was posed to me during an online interview.My doubt stems from Construction of Turbo-Alternators in section Design of Synchronous Machines of Design of Electrical Machines
Answer» Correct answer is (a) 2 Explanation: There are 2 types of rotor SLOTS in the turbo-alternators. They are i) RADIAL sort II) parallel slot rotors.

Discussion

123.	What is the use of the slot in the rotor?(a) for inserting the field windings(b) for inserting the armature windings(c) for securing the field windings(d) for inserting and securing the field windingsI got this question by my school teacher while I was bunking the class.I'd like to ask this question from Construction of Turbo-Alternators topic in division Design of Synchronous Machines of Design of Electrical Machines
Answer» The correct answer is (d) for inserting and securing the FIELD windings Explanation: The ROTORS slots are used for inserting the field windings. The ROTOR slots are also used for securing the field windings also.

Discussion

124.	The overhang has to be highly reinforced in turbo alternators.(a) true(b) falseThis question was posed to me in an interview for internship.I would like to ask this question from Construction of Turbo-Alternators topic in portion Design of Synchronous Machines of Design of Electrical Machines
Answer» Correct option is (a) true The explanation is: The OVERHANG has to be highly reinforced in turbo alternators. The overhang is DISTRIBUTED over a large number of sections which eliminates the concentration of CONDUCTORS in the overhang.

Discussion

125.	What is the voltage range for large turbo-alternators?(a) 15-20 kV(b) 18-23 kV(c) 20-23 kV(d) 20-25 kVI got this question in my homework.This is a very interesting question from Construction of Turbo-Alternators in section Design of Synchronous Machines of Design of Electrical Machines
Answer» Right option is (d) 20-25 kV For explanation: The generation voltage normally used are 15 kV for 100-200 MW machines. The voltage RANGE for the LARGE turbo-alternators are 20-25 kV.

Discussion

126.	What is the use of the laminated and transposed conductors in turbo alternators?(a) to decrease the harmonics(b) to decrease the heating effects(c) to decrease the iron and core loss(d) to decrease the eddy current lossThis question was addressed to me in an interview for job.Origin of the question is Construction of Turbo-Alternators topic in chapter Design of Synchronous Machines of Design of Electrical Machines
Answer» Correct answer is (d) to decrease the eddy current loss To explain I would SAY: The presence of LARGE CURRENTS requires the use of multi circuit WINDINGS. The use of the laminated and transposed conductors in TURBO alternators is to reduce the eddy current loss.

Discussion

127.	What is the pulsational force produced for 500 MW machine?(a) 70 kN per m(b) 60 kN per m(c) 80 kN per m(d) 90 kN per mThis question was addressed to me in an interview.I need to ask this question from Construction of Turbo-Alternators in division Design of Synchronous Machines of Design of Electrical Machines
Answer» CORRECT CHOICE is (c) 80 kN per m The best I can explain: The generator designed with low VOLTAGE GIVES HIGH currents which produce high pulsational forces. The pulsational forces can be as high as 80 kN per m.

Discussion

128.	What is the advantage of the grain oriented steel laminations?(a) it lowers the iron loss(b) it lowers the core loss(c) it lowers the heating effects(d) it lowers the harmonicsI had been asked this question by my college professor while I was bunking the class.My doubt is from Construction of Turbo-Alternators in division Design of Synchronous Machines of Design of Electrical Machines
Answer» Correct option is (B) it LOWERS the core loss Easy explanation: The grain ORIENTED steel laminations are ALSO ONE type of laminations used for the stator core. They result in the lowering of the core loss.

Discussion

129.	What is the outer diameter of the stator core and outer casing of 500 MW turbo alternator?(a) 5 m, 2 m(b) 6 m, 5 m(c) 3 m, 4 m(d) 4 m, 7 mI had been asked this question by my school teacher while I was bunking the class.This interesting question is from Construction of Turbo-Alternators topic in section Design of Synchronous Machines of Design of Electrical Machines
Answer» Correct choice is (c) 3 m, 4 m The explanation: For a 500 MW TURBO alternator the OUTER diameter of the stator CORE is 3 m. The diameter of the outer CASING is 4 m.

Discussion

130.	What type of lamination is used for the stator core of the turbo alternators?(a) stepped(b) smooth(c) interleaved(d) segmentalThis question was posed to me in exam.I would like to ask this question from Construction of Turbo-Alternators in division Design of Synchronous Machines of Design of Electrical Machines
Answer»

Discussion

131.	What is the relation of the lengths and diameters with the turbo-alternators?(a) long length, long diameters(b) long length, short diameters(c) short lengths, short diameters(d) short lengths, long diametersThis question was posed to me during an interview.This question is from Construction of Turbo-Alternators in division Design of Synchronous Machines of Design of Electrical Machines
Answer» Correct ANSWER is (b) LONG length, short DIAMETERS For explanation: The turbo-alternators are CHARACTERIZED by the long lengths. The turbo-alternators are also characterized by short diameters.

Discussion

132.	What is the core length and the shaft length of a 500 MW turbo alternator?(a) 5 m, 12 m(b) 6 m, 15 m(c) 3 m, 10 m(d) 4 m, 13 mI have been asked this question during an internship interview.I would like to ask this question from Construction of Turbo-Alternators topic in chapter Design of Synchronous Machines of Design of Electrical Machines
Answer»

Discussion

133.	How many factors does the construction of the turbo alternators depend upon?(a) 2(b) 4(c) 3(d) 6This question was addressed to me during an interview.I'd like to ask this question from Construction of Turbo-Alternators topic in portion Design of Synchronous Machines of Design of Electrical Machines
Answer» The correct ANSWER is (c) 3 The explanation is: There are 3 factors which DECIDE the CONSTRUCTION of the turbo-alternators. They are i) stator core ii) stator winding iii) rotor.

Discussion

134.	How many poles does the turbo-alternators have and what is the speed of the turbo alternators?(a) 4 poles, 3000 rpm(b) 3 poles, 6000 rpm(c) 2 poles, 5000 rpm(d) 2 poles, 3000 rpmI got this question in an online quiz.Origin of the question is Construction of Turbo-Alternators in portion Design of Synchronous Machines of Design of Electrical Machines
Answer» RIGHT choice is (d) 2 POLES, 3000 rpm Best EXPLANATION: The TURBO-alternators are made up of 2 poles. The speed with which the turbo alternators operate are 3000 rpm.

Discussion

135.	Why are the slip rings made use of?(a) they are used to provide excitation to field windings(b) they are used to provide excitation to the armature windings(c) they are used to reduce the heating effects(d) they are used to reduce the lossesI had been asked this question in an internship interview.My doubt is from Construction of Hydro-Generators in section Design of Synchronous Machines of Design of Electrical Machines
Answer» Right option is (a) they are used to PROVIDE excitation to field windings Easiest explanation: The SLIP rings are the LAST construction MATERIAL made USE of in the hydro-generators construction. They are used to provide excitation to the field windings.

Discussion

136.	What material is used to make the material of the pads of the brakes?(a) pads using asbestos(b) pads using metal wires(c) pads using copper(d) pads using the asbestos interlaced with metal wires.This question was addressed to me in an international level competition.My question comes from Construction of Hydro-Generators in section Design of Synchronous Machines of Design of Electrical Machines
Answer» Correct CHOICE is (d) pads USING the asbestos interlaced with metal wires. To explain I would say: The brakes are MADE to stop the MACHINES immediately to protect the BEARINGS. The brakes have pads using the asbestos interlaced with metal wires.

Discussion

137.	By how many minutes is the complete energy of the rotating parts and the machine is brought to rest?(a) 2 minutes(b) 1 minute(c) 3 minutes(d) 4 minutesI had been asked this question during an interview.My doubt is from Construction of Hydro-Generators in division Design of Synchronous Machines of Design of Electrical Machines
Answer» Correct OPTION is (C) 3 minutes The explanation: The brakes are so designed such that the complete energy of the rotating parts and the MACHINE is brought to rest. It is brought to rest by 3 minutes.

Discussion

138.	By how much is the rotor and the turbine runner and the hydraulic thrust requirements more than the dead weight of rotating masses?(a) thrice(b) twice(c) by 4 times(d) by 8 timesI had been asked this question in a national level competition.The query is from Construction of Hydro-Generators in section Design of Synchronous Machines of Design of Electrical Machines
Answer» The correct option is (b) twice To explain: In case of the vertical shaft generators SPECIAL features have to be incorporated in the bearing set up. This is because the ROTOR and the TURBINE runner and the hydraulic thrust REQUIREMENTS is twice more than the dead WEIGHT of rotating masses.

Discussion

139.	How are the bearing cooled in the construction?(a) natural cooling(b) forced cooling(c) air cooling(d) oil coolingI have been asked this question in an interview for job.I want to ask this question from Construction of Hydro-Generators in chapter Design of Synchronous Machines of Design of Electrical Machines
Answer» The CORRECT option is (d) OIL cooling The explanation: Oil is the material which is used for the cooling of the bearings. It is being supplied to the bearings by the PUMP.

Discussion

140.	Why are damper windings used in the construction of hydro-generators?(a) to control losses(b) to increases efficiency(c) to reduce the oscillations(d) to reduces voltage surgesI got this question in a job interview.My question is taken from Construction of Hydro-Generators topic in division Design of Synchronous Machines of Design of Electrical Machines
Answer» The CORRECT ANSWER is (c) to reduce the oscillations For EXPLANATION: The damper WINDINGS are generally USED in the construction of hydro-generators. It is generally used to reduce the oscillations in the generator.

Discussion

141.	The length of the mean turn of the winding is smallest with circular poles.(a) true(b) falseThis question was posed to me during an online interview.Enquiry is from Construction of Hydro-Generators topic in portion Design of Synchronous Machines of Design of Electrical Machines
Answer» The CORRECT answer is (a) true The best explanation: The circular poles have a lot of advantages. The LENGTH of the MEAN turn of the WINDING is smallest with circular poles and therefore cost is reduced. The copper losses are also less.

Discussion

142.	For what peripheral speed of the machine is the segmental rim on fabricated spider used?(a) >120 m per s(b) 130 m per s(d)
Answer» The CORRECT choice is (d) <130 m per s To explain I would SAY: The segmental rim on fabricated spider is USED for the machines whose peripheral speed is UPTO 130 m per s. The advantage is it is easy to transport and assemble at site.

Discussion

143.	For what peripheral speed is the poles bolted to the yoke?(a) 20 m per s(b) 30 m per s(c) 25 m per s(d) 27 m per sThis question was addressed to me in semester exam.This key question is from Construction of Hydro-Generators topic in chapter Design of Synchronous Machines of Design of Electrical Machines
Answer» The correct ANSWER is (c) 25 m per s The best EXPLANATION: The poles are clamped or fixed to the rim in different ways. In CASE of the generators the poles are bolted to the yoke when the peripheral speed is UPTO 25 m per s.

Discussion

144.	What is the range of the peripheral speeds in the water wheel generators?(a) 20 to 80 m per s(b) 20 to 50 m per s(c) 50 to 80 m per s(d) 30 to 70 m per sThe question was posed to me in exam.Question is from Construction of Hydro-Generators topic in section Design of Synchronous Machines of Design of Electrical Machines
Answer» The correct answer is (a) 20 to 80 m per s The explanation: The minimum peripheral speed in the water wheel GENERATORS is 20 m per SEC. The MAXIMUM peripheral speed in the water wheel generators is 80 m per sec.

Discussion

145.	The laminations used in the rotor body design is 1.8 mm.(a) true(b) falseI had been asked this question in class test.This interesting question is from Construction of Hydro-Generators topic in section Design of Synchronous Machines of Design of Electrical Machines
Answer» RIGHT choice is (a) true The EXPLANATION: The laminations used in the rotor body design is 1.8 MM. They are in the FORM of the OVERLAPPING segments tightly bolted.

Discussion

146.	What is the range of the length of the thick rolled sheets used in the rotor design of the hydro generators?(a) 130-180 mm(b) 120-180 mm(c) 150-180 mm(d) 160-190 mmI got this question by my college professor while I was bunking the class.The above asked question is from Construction of Hydro-Generators in portion Design of Synchronous Machines of Design of Electrical Machines
Answer» The correct OPTION is (b) 120-180 MM Best explanation: The MINIMUM value of the LENGTH of the thick rolled sheets used in the rotor design of the hydro-generators is 120 mm. The MAXIMUM value of the length of the thick rolled sheets used in the rotor design of the hydro-generators is 180 mm.

Discussion

147.	Which machine makes use of the forged steel construction?(a) low speed(b) high speed(c) very high speed(d) medium speedThis question was posed to me in a job interview.This interesting question is from Construction of Hydro-Generators topic in division Design of Synchronous Machines of Design of Electrical Machines
Answer» The correct OPTION is (b) high speed Best explanation: The FORGED steel construction is MADE use for the high speed machines. The earliest construction particularly at relatively LOW outputs consisted of a body and shaft EXTENSION made as single forging.

Discussion

148.	What factor does the rotor body depends upon in the construction of hydro-generators?(a) speed(b) voltage(c) peripheral voltage(d) powerI got this question by my school principal while I was bunking the class.My question is taken from Construction of Hydro-Generators in portion Design of Synchronous Machines of Design of Electrical Machines
Answer» The correct option is (c) PERIPHERAL voltage The explanation: In the hydro-generators the SALIENT POLES are ATTACHED to the rotor body. The type of rotor body used depends in general on the peripheral speed.

Discussion

149.	In what type of generator is the thick rolled steel discs made use of?(a) generators running at 400 rpm(b) generators running at 500 rpm(c) generators running at 600 rpm(d) generators running at 600 rpm and aboveI got this question in an online interview.Enquiry is from Construction of Hydro-Generators topic in section Design of Synchronous Machines of Design of Electrical Machines
Answer» Right ANSWER is (d) generators running at 600 rpm and above For explanation I would say: Another type of rotor construction MADE use of in the hydro-generators is the thick ROLLED STEEL DISCS. It is made use for the generators running at 600 rpm and above.

Discussion

150.	How many steel brackets are used along with the support to steel rings?(a) 5(b) 7(c) 4-6(d) 5-9I had been asked this question in my homework.My question comes from Construction of Hydro-Generators in portion Design of Synchronous Machines of Design of Electrical Machines
Answer» RIGHT answer is (c) 4-6 Easy explanation: During the process of bracing ONE or two circular steel rings are used to SUPPORT the OVERHANG. Along with the steel rings 4-6 steel brackets are also used.

Discussion

Explore topic-wise InterviewSolutions in .

Fractional windings are invariably used in synchronous machines.(a) true(b) falseThe question was asked in exam.Question is taken from Armature Design topic in section Design of Synchronous Machines of Design of Electrical Machines

When is the range of the number of slots per pole per phase in the salient pole machines?(a) 2-3(b) 3-4(c) 2-4(d) 2-6The question was posed to me in final exam.My question is based upon Armature Design topic in chapter Design of Synchronous Machines of Design of Electrical Machines

The value of slot pitch depends upon the voltage of the machine.(a) true(b) falseThe question was asked by my college director while I was bunking the class.My enquiry is from Armature Design in division Design of Synchronous Machines of Design of Electrical Machines

The single layer windings have higher efficiency and quieter operation because of narrow slot openings.(a) true(b) falseI have been asked this question in an internship interview.The doubt is from Armature Design topic in division Design of Synchronous Machines of Design of Electrical Machines

How many factors are related in the selection of the armature slots?(a) 5(b) 6(c) 7(d) 4I have been asked this question in an interview for job.My doubt is from Armature Design topic in chapter Design of Synchronous Machines of Design of Electrical Machines

How many factors does the design of armature of synchronous machines depend upon?(a) 2(b) 4(c) 3(d) 5I got this question at a job interview.This question is from Armature Design topic in portion Design of Synchronous Machines of Design of Electrical Machines

The rotor is slotted for one-third of its periphery.(a) true(b) falseThe question was asked in an interview for internship.Question is taken from Construction of Turbo-Alternators topic in division Design of Synchronous Machines of Design of Electrical Machines

How many types are the rotor slots distinguished into?(a) 2(b) 3(c) 4(d) 5The question was posed to me during an online interview.My doubt stems from Construction of Turbo-Alternators in section Design of Synchronous Machines of Design of Electrical Machines

The overhang has to be highly reinforced in turbo alternators.(a) true(b) falseThis question was posed to me in an interview for internship.I would like to ask this question from Construction of Turbo-Alternators topic in portion Design of Synchronous Machines of Design of Electrical Machines

What is the voltage range for large turbo-alternators?(a) 15-20 kV(b) 18-23 kV(c) 20-23 kV(d) 20-25 kVI got this question in my homework.This is a very interesting question from Construction of Turbo-Alternators in section Design of Synchronous Machines of Design of Electrical Machines

How many factors does the construction of the turbo alternators depend upon?(a) 2(b) 4(c) 3(d) 6This question was addressed to me during an interview.I'd like to ask this question from Construction of Turbo-Alternators topic in portion Design of Synchronous Machines of Design of Electrical Machines

The length of the mean turn of the winding is smallest with circular poles.(a) true(b) falseThis question was posed to me during an online interview.Enquiry is from Construction of Hydro-Generators topic in portion Design of Synchronous Machines of Design of Electrical Machines

For what peripheral speed of the machine is the segmental rim on fabricated spider used?(a) >120 m per s(b) 130 m per s(d)

The laminations used in the rotor body design is 1.8 mm.(a) true(b) falseI had been asked this question in class test.This interesting question is from Construction of Hydro-Generators topic in section Design of Synchronous Machines of Design of Electrical Machines

How many steel brackets are used along with the support to steel rings?(a) 5(b) 7(c) 4-6(d) 5-9I had been asked this question in my homework.My question comes from Construction of Hydro-Generators in portion Design of Synchronous Machines of Design of Electrical Machines