8 Electrical Interview Questions - أسئلة لمهندسين الكهرباء فى المقابلات الشخصية

1) why transformer cannot rotate though the principle behind induction motor is similar to a transformer

2) WHY THE +VE POLARITY OF 48V DC POWER SUPPLY IS USUALLY GROUNDED

3) what are the types of control panel used in industries & all electrical purpose

4) suppose we using 3 phase motor of 440 v means what range of C.T. is require for measuring current , the rating of motor is 1HP

5) What are the differences between ELCB and RCCB

6) will the turbogenerator operate on leading power factor with out modification in the stator winding

7) i want to know is it possible to generate usefull power by coupling generator with motor & supply gives to motor by battery source then generator generates power. remove the battery source given to the motor & feed the supply from some of the generated power supply to the motor & motor runs continously. generator generate power contnously.is it possible ?

8) Inductor and capacitor........power in one phase and ...... in it another phase

9) Iam deepthi.i completed my b.tech from electrical engineering.i want to prepare for civil services.i dont have much knowledge about these exams,but i have great zeal of cracking exams.plz provide me suggestions to which options i can select for optionals

10) suppose we using 3 phase motor of 440 v means what range of C.T. is require for measuring current

11) How we can calculate the Amps for the cable Ex:- For 1sqmm wire how many amps we can draw (calculation)

12) what is the meaning of bus? 2. what is the dc transformer? How it work 3.what is the function of the serge absorber? 4.How the CT and PT rating calculate/

13) what is bus pt and what is the function of it

14) i have applied for the post of RRB section engineering chennai board please send me previou papers and solved answer. my mail id jagarapusrinivas@gmail.com

15) what is two wattmeter test

16) we have 3 single phase transformers. how will we generate 6 supply from 3 phase supply input

17) protection used for alternator , feeder , transmission line

18) what is merz price protection

19) what is rise time and half time

20) what is surge impedence loading

21) i have three phase 25kva transformer but there is two phase line how can i connect to the two phase line

22) What is RTCC panel and why it is required

23) What is the difference between a 3 winding and 2 winding Potential Transformer

24) how we can calculate cable size for any load & any type of cable material

25) why transformer ratings are taken in 11kv 22kv 33kv but not in 10,20,30kv

26) Why generally the Rating of Transformers are in additions of 11 i.e. 11 kVA, 22 kVa, 33 kVA, etc

27) Is there any problem ,if R-Y-B voltage is constant , but the air compressor taking one phase high current.what is possible causes.the said compressor is very new.(55kw)

28) Inductor and capacitor ........ power in one phase and ...... it in another phase. if any body found this gaps answer.please sent me to habib_eu2008@yahoo.com

29) CAN ANY ONE EXPLAIN THE KNEE VOLTAGE OF THE CT

30) can u tell the difference between star - star transformer and delta to delta transformer

31) We have received supplies of the ordered material. payments against the supplies also released. Where ST paid 4% against form C. Meanwhile it has been observed that 25% of material supplied was defective. Please suggest whether the issuance of C form from our side would be stopped till settlement of liabilities

32) For R-L or R-C ckt,time constant formula is L/R and RC respectively and its unit is in sec.Pls tell me the derivation

33) what will happen at the time of CT saturation?and what will be the Relay's function at the time of CT saturation?

34) Tell me about yourself. ……………………………………. Why did you leave your last job? What do you see yourself doing five years from now? Ten years from now? What are your long-range career objectives? Why did you choose this career? How well do you work with people? Do you prefer working alone or in teams? How would a good friend describe you? What would your last boss say about your work performance? Why should I hire you? What makes you qualified for this position? What do you think it takes to be successful in a company like ours? In what ways do you think you can make a contribution to our company? What's the most recent book you've read? What two or three accomplishments have given you the most satisfaction? Why? Describe the most rewarding experience of your career thus far…………… Why did you decide to seek a position in this company? What can you tell us about our company? What do you know about our competitors? What two or three things are most important to you in your job? Are you willing to travel for the job?

35) what is open star connection or open delta

36) How to determine the breaking capacity such as break down current and break down voltage for VCB and CT's.

37) How to determine the short circuit current for breakers and VCB

38) what is meant by mimic diagram ?where it is used ?plz explain briefly

39) Which ciass CT can be use in diff. protection. Can be use 5p20

40) why generator and t/f ratings given in kva & motor rating is in KW

41) Why birds seating in HT line does not get shock? If person hangs in HT line (single hand or both hands) does he get shock

42) How much kv gas generator is needed to run 2 hp and 1 hp airconditioners, plus a refrigerator and 4 Tvs

43) What is the function of stater in tube light circuit

44) What is rotating magnetic field?Discuss elaborately

45) What is the working principle of ceiling fan

46) difference between shunt coil and tripping coil

47) Can anyone explain me about the capacitor calculation

48) What is the exact load current needed for a place which has 100nos of bulb of each 100w

49) How you calculate the repturing capacity of a HRC fuse

50) what is the rating of boiler

51) what is the diffrence between dol and star delta strater? why star delta starter used instead of dol

52) why generator and t/f ratings given in kva

53) what is the diffrence between kav and kvar

54) why in electric train we can't feel current & generally we have get socked in our normal electricity

55) in ring main system we use the isolater b/w transfer bus and main bus if we r not use isolatar than wat will be the effect in our sys

56) What type of fittings and electrical accessories can be install in radiation area

57) what are the effects on an power plant and consumers if the power factor is increased or decreased

58) what is the calculation method to design core and winding of a 200kva 3phase distribution transformer

59) I am having dual speed motor of cromton greaves make of 3.7 KW -1400 rpm and 5 KW - 900 rpm. Please let me know groups and winding connction for rewinding purpose

60) What is the maximun current carring capacity in per phase for three pole 100anps rating ncb

61) have seen one 8.4 MW synchronous motor in a plant located in bellary it is fixed with brushless rotary rectifier ,anybody can explain its start up principle

62) Need help. 3 phase system. Neutral line arced and melted upon connection of connector with 3 phase power. Why would that happen?

63) Dear sir, In our plant have Station Transformer having capacity,i want to know, why LV side 40 - 40MVA is given? & how we can get 6.3 KV supply from tertiary(i.e. Open delta connection), Vector Group YNyn0 - yn0 +d MVA Rating 80MVA / 40 - 40MVA + 26.7MVA Voltage rating 420 (Tap range +6,to -10)81.25% /11.5KV - 11.5KV +6.3KV

64) what will happen if a cw rotating altenator being synchronized to ccw rotating altenator

65) explain why tap changer is always connected to high voltage winding side of the transformer.

66) explain why the secondary terminal of current transformer should not be lift open circuited.

67) While testing the value of the resistance for the earthing rod, two auxillary rods are connected to the earthing tester.What is the working function of a earth tester?

68) please forward me the type of questions which would rise while me attending to 33KV Electrical License to my mail ID:vadrevu_raghava@yahoo.co.in

69) if 300 hrs not comleted at wat interval b.c,d checks og take place

70) what is the formula of knowing the clabe size on any load?

71) If excitation will increase, then what will be the effect on power factor? Will it decrease or increase?

72) how to measure the current by compact digital equipment with dislay which fit inside any equipment

73) How to test Power Transfomer vector group?

74) n UPS what does 600va reffer to?

75) Why do power lines not short out when they fall into water

76) expansion of rccb

77) How the CT and PT ratings are calculated

78) What is harmonics and how the 1st,2nd,3rd etc harmonic levels

79) how we calculate the 30 KW 3phase electric motor current on noload

80) which type of starter is suitable for single phase motor

81) how is working d.c amps meter?how to connect the dc ammeter inthe circuite

82) Why dose an electric meter record KVA when there is no load on a 500 KVA transformer

83) what is the ambient temperature of transformer oil & winding?

84) why breather cap filled with oil?

85) Isi standard of lux level required / to be maitained in different working place general & in textaile industry

86) s it necessary to seperate the DG earth grid with Electricity Board earth grid for protecting the DG set. if yes why?

87) Basic philosophy of applying 3P tripping for uptill 132KV switchyards & for 132KV & above 1P/3P tripping is used

88) what is the working principle of smoke detector in fire alarm system

89) IN 1000kva transformer where the oil and winding temperature sensors is connected

90) why we avoid parallel operation of diesl generator

91) can any one list the class-a, class-b & class-c trips of power generator

92) MCB Rating

93) How do you protect your appliances from harm in case of neutral failure in a three phase power supply set up

94) What is the function of a turbo charger in a 1000kva DG set

95) which protection used in power plan

96) why bucholtz relay placed inclined in transformer

97) why semiconductor fuse used in drive ,not ordinary

98) Meaning of CTPT ,how it works &how it measures the reading on trivecter

99) meter,&what is trivecter meter

100) What is the lifetime of a Thyristor? Is there a recommended lifetime for thyristors after which they should be replaced

101) WHY DISEL GENRATOR SET SHUT DOWN IN OVER LOAD CONDITIONS

102) in gen traf what is ONAN , ONAF , OFAF and DYN

103) what is bus duct and what is differance between bus duct and bus bar

104) Single line diagrams for star to delta and DOL starters

105) Signal transmission in sky wave propagation is due to ? a) Reforction of wave b) Reflection of wave c) Pierus through Inosphere d) None and Reason for this is????

106) The transmission does not have options: a)Partition noise b) Flicker noise c) resistance d) Short noise and reason

107) what r substations?what r there work?why voltages r incresed and then reduced during distribution of power

108) explain how the power is distributed from a power plant to a consumer.explain step wise in detail

109) what r Grid stations?what r there role. Explain in detail

110) What is an Air Compressor

111) Please clarify 1. Icw: rated short circuit working withstand capacity 2. Icu: Rated ultimate breaking capacity 3. Ics: Rated service short circut withstand capacity 4. other specification of ACB

112) What is the field weakening mode of a ac motor?

113) What is polarisation index value?.(pi value) Simple & brief definition of polarisation index

114) how can we decide where we have to DYn11 or other vector group transformer

115) how can we decide where we have to DYn11 or other vector group transformer

116) Can 4pole (3 phase+neautral )RCCB proper functioning in only 3 phase load (no neautral, no Earth

117) I WANT YHE TECHNICAL AND ELECTRICAL SPECIFICATIONS OF 2x4MW 11KV 2x10MW 11KV 2x25MW 11KV 2x100MW 11KV HYDEL POWER PLANT i.e PROTECTION SYSTEM,MONITORING,CONTROL SYSTEM,GENERATION,SYNCHRONISATION,METERING PLEASE

118) please tell me the all the spcications of the 100MW 11KV HYDEL POWER PLANT SPECICATIONS

119) how to match 0 -10V with 4 – 20mA

120) What is Earthing

121) what should we do when the CT secodary gets open? how do we short circuit it? using tester or screw driver? not dangerous

122) how you configure motorvision relay (L&T make)from DCS

123) can we connect both delta and star to the transformer secondary and for what reason?

124) which pump is suitable for home use ?

125) what is MC 61 relay

126) How can I calculate the fault level of a transformer. 1. If fault is 3phase fault 2. If fault is 1phase fault 3. If fault is 2phase fault Dear all geniouses, can you help me by giving answer.

127) role of europe union in UK safety legistlation (electrical safety)

128) wat is the criteria we use the diff. Relay

129) how to set the time in digital timer

130) Why A.C. capacity given in Ton. Ex. - 1.5 Ton

131) How to calculate the size of window A.C. for 200 Sq. ft room

132) How can we find out LT UG cable fault (size,from-4*25mm sqr to 4*300mm sqr)? How mani types UG cable faults

133) What is the Polarisation index value ? (pi value)and simple definition of polarisation index

134) How many types of lightings are there

135) how many types of ratings are there of transformer

136) i am working in automation feild my question is that how to find the KVA of transformer

137) what is the advantages of having in-built acvvvf (without seperate inverter in the control panel)in the drive system of elevators

138) if we convert ampers into kwh or mwh ,which one formula use by us,pls tell me

139) iam working in power plant. In hot places tube lights are glowing at the end portion only. what is the reason for that

140) How to arrange a hous hold earthing system to keep minimum earth resistance( below 7ohms)

141) which stabilizer is better ? AVR, Servo Stabilizer, Static stabilizer etc & why explain it

142) what are the main faults that occur in stabilizers? How they corrected and resolved ? Types of stabilizers ?

143) How to arrange a hous hold earthing system to keep minimum earth resistance( below 7ohms).

144) What is the recommended voltage gap between Live and Earth and ,Earth and Neutral.If these are exceded what is the solution.

145) what are the breakdown voltage rating of mini- curcuit'transfarmer

146) can mini-curcuit supply MIL-tested transformer

147) i want to learn control schedule for 11kv panel? can any one send the detailed control schedule

148) What kind of battries are generaly used with Disel Generator

149) How does a television work

150) keeping in view of parallel operation which of the 3 phase transformer connection are possible? a)delta-delta to delta-star b) delta-delta to star-delta c) star-star to delta-delta d) delta-star to star-delta

151) what is th basic difference between a d latch time line and a d flip flop time line

152) what is the meaning of WYE and DELTA in Electric meter

153) Please help me.What are the difference between two wire, 3wire, and 4 wire in electric meter

154) what is the difference between single phase, 2 phase, and 3 phase in electric meter

155) what is 3 phase motors

156) what is 2 phase motor

157) what is single phase motor

158) What is the difference between single phase, 2phase, and 3 phase motors

159) what is power

160) how calculate the current faut level

161) advantages of vvvf drives over non vvvf drives for EOT cranes

162) what is the thumb rule to know current carrying capacity of copper conductors of different size

163) why the difference arise between HT reading & LT reading (submeters fixed in complexes, apartments etc)if the power factos exceed from 0.9 to 1 can the ht meter reads fast

164) where this neutral connection goes after returning from the load(home ,factory,industries).Is it grounded at the transformer side or atthe generator side .If it is grounded then we also ground the earth connection.is there any problem with this

165) why protection and metering CT's are always connected in star why not in delta

166) why we are used D.c. voltage in L.T.side or controling side.we can use UPS also ,in place d.c. Voltage

167) why we r used APFC Panel in industrial area.when P.F. low then wat will be the effect in our system

168) WHY FLEXI LINKS ARE USED INBETWEEN GENERATOR TERMINAL OUTPUT & BUS DUCT CONDUCTOR

169) How i can decide that HVDC line is best for transmission.

170) Can u tell me design of switch yard

171) How many types are using in 220kv/400 kv swith yard

172) What is fuction of NGT/NGR using in Generator

173) how does the rotating m.m.f is produced in the 3-phase induction motor and how the poles are created in 3-phase induction motor

174) What is the meaning of CT 40/5, 100/5 or in HT lines 100/1

175) How to calcute the cable size for both HT and LT please specify the formula for that Regards Chethan C

176) generally on the roadside v hav 11kv line which is being step down to 440v line to line....so any1 can tell me which type of transformer they r using whether it is star to delta,delta to star etc.

177) what is the order of mgnetiation current in a current transformer of 1000A/1A ratio

178) why 3 phase is preferred than 1 phase

179) can any one suggest websites having study maetrials for the electrical students

180) why dc current is supplied in america rather than ac

181) What is the difference b/w Earthing and Grounding

182) whats the one main difference between UPS & inverter ? And electrical engineering & electronics engineering

183) what are the differences between 'exhaust fan', 'heavy-duty exhaust fan' & 'super heavy duty exhaust fan'. what are their power ratings

184) wat is the purpose (or)function of regulator

185) wat is the purpose of stabiliser?

186) wat is the advantage of induction motor

187) wat is diffrence between 1-phase and 3-phase induction motor?

188) what is meant by magnetic flow meter ? explain its working principle

189) What is surger vector in 33Kv transmission feeder

190) We have AC power generator of 8MW which is paralleled with 33Kv EB grid. Some times our HT breaker gets trip off due to surge vector problem. How to over come it? Is there any device to observe the surge and avoid tripping

191) If a surge divertor is required to be protected by 32 amp C Curve Circuit breaker does this limit the amount of protection from surges that you will achieve

192) what is nuetral grounding

193) what is field flash

194) how to diffrentiate between ac & dc motors from a distance

195) Motor and transformer working with same principle so why motor rotates while transformer not

196) what is impedence (Z) of transformer, what indicate in transformer , which perameter indicate in transformer

197) BRIEFELY EXPLAIN MEGGAR PRINCIPLE

198) EXPLAIN THE WORKING OF SERIES REACTOR IN HT CAPACITOR BANKS

199) WHAT IS THE USE OF ANTIPUMPING CONTACTOR IN HT BREAKERS

200) HOW CAN YOU CALCULATE PRACTICAL EFFICIENCY OF A ASYNCHRONOUS INDUCTIONMOTOR OF 7.5KW,& MOTOR IS RUNNING WITH AVOLTAGE OF 410 VOLTS,& TAKING CURENT OF 13 AMPS

201) give me a clear defination of inductance,and how can u calculate inductance of a motor

202) what is the effect of leading power factor

203) how external lighting design? please give example

204) what is the use nuetral wire

205) Why 60Hz frequency is used in America what are all the benefits

206) how we protect the motor & what are the components required for that

207) what is the use of earthing.

208) What is the difference between INVERTER and UPS

209) In 90 kva alternator that produce the output voltage is 115(p-n),200(p-p) at 1500 rpms means what ampere it produced

210) Suppose the incoming power is 11 kw, but the load require only 8 kw means how can we save or use the excess power

211) The potential difference between a phase and neutral is 230v , but the potential difference between two phases is 400v. Why

212) what is the importance of Partial Dischage test for Electrical Equipments

213) What is the importance of Form B to state Electricity Boards

214) What is Ten Delta Test

215) if we use fuse in neutral what will happen

216) How can we calculate the rating of capacitor bank to be connected for a particular load(ex.100kw)to improve the power factor from 0.8 to 0.9?

217) what is the difference in MCB, MCCB, RCCB, ELCB, & MPCB (motor protection circuit bracker)

218) How to calculate the heat load for a electrical room what is meant by frequency

219) DG lube oil and waste oil how to dispose outside and there is any authorised vendors will be there for this

220) how to calculate optimum loading for transformer

221) IF THE LOAD OF TRANSFORMER IS GETTING MORE THAN ITS RATING,,,THAN HOW TO OVERCOME THIS PROBLEM? SUPPOSE THEE RATING OF TRANSFORMER IS 315KVA AND THE LOAD IS GOING BEYOND THAN THE RATING SAY AROUND LOAD: 352KVA... THAN HOW CAN WE SOLVE THIS PROBLEM WITHOUT DEDUCTING THE LOAD

222) why we oltc on hv side of tranformer only

223) motor and transformer working with same principle so why motor rotor was roted and transformer not roted

224) why ht motor connection in star

225) What is difference between Earthing, Ground and Neutral

226) when the size of the cable used for the ht voltage is 300sqmm then what is the size of the conductor of each Phase

227) whye the current increases in the motor when the load on the motor increases

228) explain supply side and demand side energy management with advantages & disadvantages

229) explain impact of tariff on energy management..? and what is ABT tariff

230) importance of reactive power management

231) differtiate between energy consevation and energy efficiency

232) what is CRGO Transformers

233) tell about gas insulated substation?which gas is used for that substation?above which rating we are used this substation?how we take maintenance in that substation?it means substation fully shutdown or live condition?if live condition means how?pls clear this things

234) the resistance of wire having length X M is R OHEM if i streched the wire to dubble length what will be the resitance

235) what is the type of winding connection( star or delta) in 1HP to 5HP motors. How to check the motor winding connections( star or delta) if not provided in the nameplate

236) Which supply is using for train AC or DC & what is the voltage

237) What is the meaning of In,Io & Ir in Circuit breaker? How to calculate

238) what is mean by power factor

239) In wat way the power compensation takes place when a statcom is connected in a transmission line

240) Application wise, where we should use AC motors and where we should DC motor

241) Why HT cable have only 3 core

242) how to calculate the powerfactor in induction motor having name plate details , for example 1 h.p motor 1.86 A 415 V how we can select MCB ratings according to Voltages, Curves

243) How Much Capacity of Diesel Genset is suitable for 20 no.s of 1.5ton AC's & Why

244) How can we calculate strength of copper hich is supplying electric power to heater and in it hold the heater also and what r all types of forces which is acting on it.

245) What are the functions of different Parts of Alternator

246) What are the different parts of Alternator and how it works

247) Can HT cable(11kv cable) be used for 415V, 700A requirement

248) Can we inject more current in ct primary paralleling 2 loading transformers/Injection kit at a time?let ct ratio be (5000/1A)(per kit rating 2000A range),i need to inject 5000A,if this cant b done means wat is d optional

249) WHY IN AC DRIVES,INPUT PHASE CURRENT SHOW UNBALANCE

250) What is mean by power factor

251) What is mean by hormonics

252) why D.C excitation is given to sunchronous motor

253) what is proper capacitor placement? How to evaluate capacitor size

254) What is EMC filter in VVVF Drive

255) What is D check in a Diesel generator for 1000kva DG

256) What is C check in a diesel generator and what are parts and what has to be done during the C check

257) why the frequency in india is 50 50HZ why we not select the o ther frequncy range

258) Why HT motors are connected in star

259) If we are importing real power & exporting reactive power then what will be the effect on our system

260) how we can save the power ? suppose the electricity board gives 11 kw , but the machine require only 8 kw means how we can save the exese energy

261) Relation between Sq.mm of wire and Its current carrying capacity

262) How to select KW/HP rating of motor for particular application? Is there any relationship od RPM

263) what is the relation between Sq mm of wire and its current carrying capacity

264) WHY IL=IPH IN STAR AND WHY IPH=IL/1.732 IN DELTA? WHAT IS REASON BEHIND IT

265) How to select HT/MV cable size

266) how to calculte capacitor range for single phase induction motors??pls tel

267) tell how current tranfomer works

268) what is the switching substation

269) what is gridrotor resistance starte

270) why transmission voltages are in multiple of 11kv

271) how tan-delta test is performed

272) what is earth-fault?when it occurs? to check where it occurs what type of test should we do

273) two generator runnig with parallel but only one NGR on And one off Why

274) if two bulb of 50w &30w apply in series having 230v the which bulb glow bright ,why

275) How to select the cable size for the given load ?Pls explain the Formulae

276) importance of air gap in transformer

277) In a three phase transformer(delta/star connected)when i touch one end of the bulb in any one phase and other end to earth..will the bulb glow or not..if not why?..i'm touching the bulb in star connected side

278) how will you determine the short circuit capacity of a network

279) if v r considering a 4000/1A ct,if v inject 1 amps in secondary core wat happens?(consider as 2 core ct,each for metering and protection)

280) what is the length of air terminal in lightening arrester system

281) Is there a possibility to use such a treshold voltage for the NMOS part of a CMOS circuit that during the switching it will start conducting only after the PMOS part will be already closed, by this eliminating the leakedge current? Please note, I'm not asking about the well bias in standby mode, but about the "antileakedge" measures during normal operation

282) What happen if we have run 415 V,50Hz designed motor at on 480V,60HZ

283) what is the highest transmission voltage in India till now

284) when motor taking high amp what happen

285) what is the material use in bus bar & why

286) what is the working of vfd drives

287) what is working of no & nc

288) what is the working of ups

289) tell me working of air circuit braker

290) what is amf panel & how it is working

291) what is the range of using dol starter & star delta starter

292) What is formfactor

293) what is the problem of generator over voltage.?except automatic voltage regulator card

294) How to select the rating of a CT used for REF protection

295) The rating can be of equal rating of Phase current or neutral current rating

296) ANY ONE TELL ME ABOUT generator synchronization panel panel to synchronise 3 gen of 250kva both automatic and manual. 2 gen output vol 415 3ph, 1 gen output vol 400 3ph SEND THE DETAILS DIAGRAM ON THIS EMAIL ADDRESS ayazleo@hotmail.com as soon as possilble best ragrds electrical engineer ayaz mahmood SAUDI TECH

297) What is the scale analysis for condensor of HVAC system

298) Is it mandatory statutory requirement of transformer oil filtration annualy despite oil is withstanding required dieelectrical strenth and all others parameters

299) What are the parameters of water ( Water quality )to be monitored in Centralised HVAC ( water cooler chillers )

300) Why DC weldings sets preffered over AC considering human safety aspects

301) what is the principle of motor

302) WHAT IS PRINCIPLE OF TRANSFORMER

303) what is principle of DG

304) what is the principal of braker

305) How to identify the whether its an isolator or Breaker in MDB

306) What is the difference between MPP, APP, Mixed Dielectric power capacitors? Which technology is superior in current scenario

307) in trains i have seen the terminal which is connected at the top of the train is positive .where is negative ? track? i dont think so

308) difference between ac and dc motor

309) why contactors are used ...? is contactors and relays are same

310) usually why bettery voltage are 1.5V, even if you open a 9V battery there are six 1.5V batteries in series. is it not possible to increase this voltage other than putting in series

311) define reflection method

312) If fault current is 52 kA then what will be the CT specification

313) what is AVR in alternator how its work?

314) why DG rating in kva

315) why DG battery blast

316) What happen while we measure the Current in Rotor

317) what is different the DOL Starter and Star Delta STARTER

318) What is the harm if we install primary side 11 KV VCB at a distance of one Km from the 11/3.3KV 12.5 MVA transformer through 11 KV cable

319) what is numerical relay explain its operation

320) WHY TRANSFORMERS ARE RATED IN 11KV 22KV 33KV Instead off 10kv 20kv 30kv

321) Why no-load primary current is very small as compared to full load current in transformer (as 1% of full load current

322) Why not LED burn after showing alarm,as Alarm volt is 11- 13,But LED is of3 volt,why it isnt Burn

323) When Alarm report at LED,Alarm volatge is 11-13 Volt But LED is of 3 volt.then why not it burn

324) How to convert from HP to BHP please explain

325) My requirement is 1VA,50/5A Current Transformer for Metering .If I select 15VA , 50/5A CT.Is there any possibility of Technical Problem

326) Why the capacitor are connected in Delta(Three Phase) for power factor improvement

327) will we get shock from dc

328) what is surge impedance loading and it's significant in power system

329) what is effect of brush shift in machine

330) Why arc quenching is used in Diode

331) Why MS rod or flat are used in stead of GI rod or flat in switchyard earth mat

332) what are the main parts of DG? explian thier functions

333) what is the means of dedicate earthing

334) what happen if position of GNA and MNA is changed in machine

335) low frequency protection why recommend

336) What will hapen if we run generator below 47.6hz frequency

337) why neutral can not used in three phase motor connection

338) Is it possible to power factor more than unity

339) why neutral used in three phase motor connection

340) Why the capacitor are connected in Delta(Three Phase) for power factor improvemen

341) why neutral can not used in three phase motor connection

342) Is it possible to power factor more than unity

343) if we want to increase the back up time of an UPS what should we do ? if we want to decrease the charging time of a battery/batteries attached with the UPS what should we do

344) how one can know the charging time, discharging time of a 12 VDC battery ? If i have a battery of 12 VDC , 4.0 AH , how long will it take to charge from a charger (power supply) of input 220 V , Output 15 V and output current of 3000 mA and how long will it take to discharge whether using or not ? How much backup will it give

345) what are fluorescent lamps (fluorescent fixtures) & what are incandescen lamps (incandescents fixtures) ? differences between these two

346) which type of A.C motor is used in the fan (ceiling fan, exhaust fan, padestal fan, bracket fan etc) which are find in the houses

347) although ckt breakers have taken the place of old fuse. But instead of it , these older ones are still used in the industries and homes ? why .... what are their advantages and disadvantages ? which one is leading and winning the race and competition

348) How one can check the charger of the mobile phone or any other charger .......... that is it working ? if , working is it delivering the required supply which is needed by the battery to charge properly

349) How one can say about a device (e.g: a light holder contains 20 or 30 L.E.Ds which glows when power supply is off, from which source they are getting the supply..... battery or capacitor) without removing and opening up its case

350) why we not connect the 12 V batteries in parallel to get the more backup supply for an UPS ? wheter off line or on line UPS

351) I am designing new project sub station with 220 kV / 11 kV, 40 MVA capacity. This project have many recifier sets, which can generate 3rd harmonics. Now I have to select vector group of This transformer. To minimise 3rd harmonics, what care should I take in selection of Transformer Vecrtor group? If it is Y-Y with open Delta tertiary then what should be the rating & voltage of Tertiary Winding

352) Define motor & pump

353) for 5KW resistive load can anyone please suggest me whether to go for UPS/Inverter or Generator depending upon cost calulations

354) wHAT IS THE DIFFRENCE BETWEEN EARTHED AND UNEARTHED CABLE (XLPE)

355) which type of motor is suitable for water suction pump

356) how we do Vector group ,magnetic balance and tap changer test in Transforme

357) What is the significance of vector grouping in Power Transformers

358) if d gen is 50kw,load is 60 kw,hw d gen ll supply d remaining power

359) suppose generator rating is 50 kw,load is 25 kw,hw much d generator ll generate?what about d remainin power

360) what happen if we give 220 volts dc supply to d bulb r tube light

361) which fault is severe and why?between lll fault and lllg fault which fault is severe and y?

362) n CDG type IDMTL realy O/L , E/F, O/C which are used for out going feedrs,on R-phase o/c element, Y-phase , e/f elecment and on b -phase o/c element will be connected . Why the earth fault on center phase only, why not on other two phases

363) what will happen when power factor is leading in distribution of power

364) I have 480V Single phase and I am trying to figure how big of a transformer (KVA's) and Primary breaker size I need to provide 200 Amps at 240V for a building

365) Transformer TTR test procedure

366) what the function breaker failure scheme, how is it operated

367) what purose of the double circuit transmission line phase of the line phase changed for circuit-1 for Circuit-2 R-Y-B B-Y-R

368) how to find impedance , mutual indatnce in transmission lines

369) what the purpose of transmited high voltage in over head lines

370) why Line voltage =1.732XPhase voltage what mean by 1.732

371) what is the diffrence between voltage and current

372) TO operate transformers in parallel, vector symbol of the both should be same.If one transformer name plate is not there, how can we conclude that whether the transformer is having the same vector symbol or not

373) Can any one provide the inspection procedure of MIMIC for VFD panel? Details: If someone wants to have a mimic in the VFD panel what are inputs considered for the mimic(like on,off,trip) whether we are able to add speed variation in the mimic(if so how can we get) and what are the parameters to be checked in the MIMIC during inspection

374) How to size a transformer which will supply power to 550kW,690V motor starting with VFD

375) Describe: Energy efficient motors

376) How to calculate total harmonic distortion level(THD) in VFD? and how can we reduce harmonics

377) what is the effect of power factor of machines in starting current

378) What is K-rated transformer? What is the use of it? What can be the size(pls provide calculation if possible) of K- factor transformer for 550kW,690V motor operating with drive Vfd

379) How can we calculate the capacitance of generator's

380) if the back emf eqution for dc motor EB=(QPNZ/60A) THEN what is the value of A for PMDC MOTOR OR how can dicide the value of "A

381) what is threshold voltage for a relay what does it exactly means ?whats its value in our indian transmission system say 11kv feeder RMU relay

382) WHAT IS DIFFERENCE BETWEEN idmt and instentanous relay? is idmt is used as back up protection or else?or when instantenous relay saturates IDMT will operate?

383) What is relation b/w Transmission Lines & Communication Line

384) 11KW Delta motor is taking about 44Amps in star and goes upto 70Amps in delta and trips OFF. The rated current is 26Amps. Application is for the blower. The motor takes ( no load without coupling impller ) only 2.5A and 5Amps in star & delta starter test.Need to know why its taking high current.

385) Different methods of Improving power factor,especially in wind sector

386) Why Batteries are rated as AH i.e AmpereHour,and its formula to converting AmpHour to Amp

387) Why 4 pole generator generates more power and 6 pole generates less power campare to 4 pole

388) How we can convert H.P into KW or Vice versa

389) how invertor convert the dc into ac give brif detail

390) Wtat is vaccum currcuit breaker.define with cause of used.and where be use it Devise

391) what are the major & minor faults that occur in an inverter and in UPS ? And how to repair and resolve them

392) What are the steps for Testing of 6.6KV HT Panels

393) What are the Steps for Testing of 20MVA (make:-CGL) Transformer? How many Test that we have to do

394) Which motor has high Starting Torque and Staring current DC motor, Induction motor or Syn motor

395) How can we find out earth leakage,(shock)in side the house?.. (with out ELCB

396) what is the earth resistance

397) what is the function of Choke

398) what is ASCR cable and where we use it

399) what should be the minimum rating for using HT Motors

400) what is interlocing and what is the purpose of this\

401) What is Biased Generator Differential Relay

402) What is mean by PID controller? And what is its Long form+

403) we have 1000 litre water tank,it located at 25m hight from ground level,the water level on 10m below from ground level.for fill the tank within 1 hour,how much of motor rating(HP) want to select

404) what are the energy savings methods that are existing in coal based power plant?

405) what is the difference between concentrated winding and Distributed winding in motor

406) Please tell me 1 ton = How many Kilowatt (Electrical)

407) why star point of motor shall not be grounded?

408) what is the meaning of ceiling voltage in Generator excite

409) Why thwe Direction of Rotation of a TABLE Fan & CEILING Fan are different

410) how to calculate the kw, Amps consumed by a capacitor, give me the formula for KVAr into capacitance,KVAr into KW & KVA, Amps

411) where we use stardelta starter and dol starter

412) How will you Physically differentiate A.C and D.C motor?

413) What is the working of AVR in AC generators

414) How to check the specific gravity of the two 12 V batteries connected in series to a 24 V UPS and inverter ? will we have to disconnect all the connections and turn off the UPS and inverter or not ? will we have to check specific gravities in each cell of the two batteries ? what is the name of the instrument that is used to check the specific gravity and whats the procedure to check the specific gravity with it ? Thanks

415) What are the difference between these terms ? e.m.f, voltage, potential, potential difference, current etc? what are the difference between these terms ? (electromotive force) e.m.f, voltage, potential, potential difference, reference potential, reference potential difference, current. How can i explain and describe these all terms in single line each and little more explaination too thanks

416) what is the ideal earth resistance

417) Why should we use the igniter in the sodium vapour lamp

418) Why are some relay circuts designed to have the ct current flow through the neutral instead of the phase wire, such as in some diff relays

419) what is the use of power factor ? where its applicable ?

420) why the motor running in delta connection ? it can be in star

421) what is the difference between KVAR & KVA

422) what is meant by power factor

423) .wat is the negative slip region in the motor

424) i m electrical diploma holder i want to do plc $ Scada some body tell me which insitute is best for me near chandigarh

425) What do you mean by Frame 5 Gas Turbine as well as Mark II

426) why transformer rated in KVA not in KW ? we know that W= v*i

427) what deffrence between KW $ KVA ?

428) Is it posssible to obtain the higher speed(3000rpm) for adiferentiallly cascaded induction motors(with 8 and 6 poles)

429) On load tap changer (OLTC) explode?

430) Transformer Vector group: Ynd11 Rated Power: 353MVA Rated Current: 693A Voltage:294/20KV OLTC Type: T III Y1000 110/c 12193w Max Operation Current: 295A Step Voltage: 550V Arrangement in Tx windings: Y Connection Problem: Damage of Unit 1 Generator Transformer On Load Tap Changer (OLTC) Description of Incident: 9.00 a.m. :- Generator No Load test on excitation system started 10.30 a.m :- Carried out AVR change over test 11.30 a.m :- Preparation for Generator Manual Synchronizing test 12.00 a.m :- Manual Synshronizing test started. Observed incoming generator voltage higher than running voltage. CECR operator operated Generator Transformer OLTC to bring down the incoming generator voltage 12.03 a.m Generator Transformer abnormal alarm operated at Gen.Control Desk (CECR) CECR operater at Generator transformer bay informed that the transformer oil splashed out from OLTC. CECR operater informed that he heard explosion inside OLTC. Observed Oil level & Oil Flow alaram operated at Tranformer local annunciator. 12.05 am :- CECR operator 'Open Gen Field Breaker” 12.10 a.m. :- Elec1 team inspected the OLTC and found the OLTC rupture disk was broken and oil spilled at OLTC area. - Elec1 found the OLTC top cover bulging. Do anyone know why and possibility cause happen in this OLTC

431) A three phase load, around 4 km away from the 11/0.433KV distribution transformer (Neutral of Transformer is solidily earthed) and consisting of mainly very costly and sensitive electronic equipments is giving trouble due to high voltage difference between neutral and body earth. Whether this problem can addressed by connecting neutral at the load point solidly to earth?

432) how many amps in 1 KVA? V=440v, PF=0.8 and FREQ=50Hz

433) what ll happen to current if two phases get short circuited

434) what is meant by earth fault and how it happens....

435) how to amps calculate from 1KVA?

436) how many amps in 1KVA?

437) what is the diff b/w HP and KW

438) how many percent setting of motor over load relay of its full load current

439) why transformer neutrol is grounding.

440) In industries Power factor is maintained by installing a suitable KVAR bank, How is the PF maintained for domestic use, where is the capacitor bank connected

441) what is the specific gravity of fully charged battery

442) what is meaning volt-hz ration,where is necessry tomaintain and why. specialy during increase the power of generator.

443) when we given 3 phase supply to ups system, but out put comes with 3 phase + neutral how it possible? pls explain.

444) How to select a D.G set for calculated load of 110kW..?

445) why fuse not recomended to neutral

446) How do you think they do earthing or grounding in ships and aeroplanes?

447) what is EIB lighting control system? what is the advantages of this system

448) how to check dc current,how to fix ammeter in dc line

449) HOW DO A DISTANCE RELAY SENSES THE FAULTY ZONE

450) why rotor current reading is taken & why not stator

451) What is difference between miniture circuit breaker and module case circuit breaker up to 63Amp

452) WHERE IS THE LIGHTING ARRESTER SHOULD BE PLACED IN DISTRIBUTION LINES

453) why rating of motor in HP

454) how electronic energy meter works

455) How we can determine short circuiting current any plant and for example a plant which power generation is 415 volts and plant load is 500 kw

456) if you short the any 2phase(R,Y,B),why fuse get blown

457) WHY WE CAN GENERATE POWER IN 3PHASE MODE ONLY NOT IN 4 OR 5 PHASE

458) How can the direction of a three phase induction motor be reserved

459) phase clearance between phase to phase and earth.

460) how to calculate cable size for the motor

461) what is F.A.P in fire alarming system

462) what is the function of fire alarm system

463) give types of Air conditioners commonly used &its use

464) block diagram of 2 ups system connected in hot stand by mode

465) what r the safety measures in UPS ? explain all

466) what is the dedicated neutral earth in ups?

467) give single line diagram of D.O.L and star -Delta starter

468) give single line diagram of D.G distribution form alternator to main L.T panel

469) if AVR fails in D.G set, what will be the effect

470) explain safety measures in alternator

471) what r the earthing required for commissioning of D.G set

472) what type of battery used for starting D.G?state its function

473) what is H.T?specify the range

474) what is W.T?specify the acceptable range

475) what is O.T?specify the acceptable range

476) what is S.T?specify the range

477) what is L.T?specify the range

478) i am going to correct power factor of 1600kw induction motor,when i calculate capacitance of capacitor it is three time more in star connection than delta. if motor is star connected which connection i shall adopt for capacitors and reason for adopt this connectio

479) how do you calculate IKW(consumption per TR) in HVAC

480) How can i modify the design of 3 phase induction motor to be as 3 phase synchronous motor?

481) According to general circuit diagram of 1-Phase t/f , why the primary is not get short circuited ,even though the supply terminals both are directly connected through primary winding

482) What will happen if supply to three phase motor is given wiyhout inerting rotor in it?How much current it will draw

483) How the neutral earthing is connected in DG alternator

484) Explain the working principle of Synchronous Generator and Assynchronous generator

485) why we use to transmit the power in three phases intead of single phase

486) what is efficient load of transformer in percentage

487) What is the Surge suppresor? Why using in a UDB's and How it work

488) How to select Main CB Rating for 187 KW Load

489) if we know Fault level say 25 KA , How to decide busbar size for Distribution network of 1000 Amp Breaker ? Sample Calculation or Farmula Available or not

490) what happen to the voltage and current in all phases when an earth fault occur in a phase in three phase three wire system(delta connected)..

491) why AC cannot to be stored and DC cannot be transmitted

492) why are use star delta startor

493) what is the reactance,capacitance & impedence electrical armoured & unarmored Cables

494) how to calculate the loss tangent of electrical cables

495) How to calculate the current carrying capacity of electrical cables

496) what happenes if two voltage source connected in parallel will be connected to load.

497) why the voltage level is changed when the unearth cable is earth

498) Why we are measured insulation resistance applied through DC Voltage?

499) what is the differnce between vector and phasor? are both same or there is difference between two term.

500) why odd hormonics only will effect the power system.why not even hormonics

501) what is the function of commutator in dc motor

502) how to calculate the no. of earth pits required for an electrical installation

503) what is the easiest method of short circuit current calculation

504) What is the difference between Isolator & Load Break Switch

505) Can any one explain me about 2 phase motors

506) how to calculate AH of a battery

507) If one 10 Hp 3phase induction motor connected in 380volt 50Hz. and again its connected to 380volt 60Hz. howmuch currrent and power take on both time

508) what is earthing.how we make it,describe briefly

509) why use generator Earthing/Graunding

510) What is the battery voltage limit