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- Electro Mechanical Energy Conversion 1 - EMEC1
- 2017
- PYQ
**Dr. A PJ Abdul Kalam Tech University Lucknow - AKTU**- Electrical Engineering
- B.Tech
**191 Views**- 1 Offline Downloads
- Uploaded 10 months ago

NES-301 Printed Pages: 4 | (fotbwing Paper II) and RolI hlo. to be filled in your i Answer Sooks) Roll No. B.TECH. Regular Theory Examinafion (Odd Sern - III),2{}1 6-17 EMEC-T MsJt- fu{ttrks Time : 3 Hours : 100 SECTHOT{.A t. Attempt a) b) c) d) e) 0 altr parts of the lollowings : {t$x2*2(}} Write the ensrgy halance equation for mutr:r acticn and drarv power flaw diagram What is beck-emf in a dc rnctar? Defin* onr*aciance voltage" in Colmffiutation prseess What is the sffect of frequency and supply l,oltage on irori losses? Wliat afs the effects of arunattirs reaction? Diffegeniiate between.'armatur* vsltage control' and 'flux control'of dc shunt motor. g) What is the need of tertiary winding in h) transformer? Why short circuit test is performed on HV side transforrner? 3tlt112l?;016/s*80 {1i a 3* d of lPT.O.

i) j) NEE*301 What is the need of starter while starting the'dc motor? Define energy and co-energy. SECTION-B Attempt any Five questions of the fbltowings {5* 1{}:58} 1 3. 3, a) Derive an expression for Reluctance farque in rotating electrical machine. b) Explain the various phenomnn#ffi happening in electro mcchanical energy csnversion in r*tating eiectrical machines. a What ale various losses that occur in d.c. rnachines?Als*. derive tiie condition for rnaximurn effici*ncy *f a C.c. generatr.:r. 4" ' ilraw the *speed-torque characteristics' t:f C.e. shunt, series and coffilpound rnotors. A 200 V shunt fnotor has Ra: il. 1 ft, Rr: 24(r ft and roiaticnai lerss 236 w'. on full-it:ad the Einc current is 9.8 A rvith the motor runiiirig at i45fi r"p.nt" fietersnine a) b) ci {t} SSIir The mechanical power developed. The p*wer cufput. The load torque. The full load efficiency. ,}/3{}I6/54$fi (2)

t Z r,, c. Explain the procedure of O.C. and S.C. tests for a transfoflEer. How tlifferent parameters ofthe transformer -'-rv' can be detemnined from theses tests? 6. A 500 kv'A , 11ia.43 kv, 3-+ de,ltaistar connected transformer has CIn r&ted load. T'he HV *oppi, I"*;i 2'5 kW and the LV loss of 2 kW and the toial leakage reactance of 0.06 per unit, Find the ohmic values of the equivalent resistanee and leakage reecian*e on the delta side. Fi l. a) Deri';e the r-elationship betwe*n rnagpetic field en*rgy and e***nergy tbr b) s" singly-excited systern. Derive ihe emf equation for a dc generator. Two simgtre-phase fumaces I and I are supplied g0 at V hy Hleans c=f a Scott cormected transfbriner cornbination ftd hy a 3-phase 66{i0 V system. fhe voltag* of f"*u., l is leaetimg" Calculate the Iine clrrrents gn the 3-phase sicle when the furnaces take 5t)0 kW and Sgd kW; rsspe*tiv*ly * a; hi 9. a At uniq,o p"f F*rnace i ai unitv p.f. anci furnace z at 0.T p.f. what eio you rnean by "PARALLEL 0FERATI{}N of3-$ TRANSFORh{ERS"? Discuss t}re advantages and di s ad vantag$s of paral lel op sration o f J -$ tran sf*n:ners. :}{}tr/r 2/2$r6/54S$ {:} I [P.T.O,

NEE-3OI SECTION-C Note 10. : Atternpt any two questions of the followinq'- 1 {2x15=30} : write short notes on the following a) 3-$ to 2-+ connection of transfornrers' b) 3-0 to 6-$ connection of ransformers' an armature draws 11. A 4-poie series wound fan motor at 2000 r.p"tn on a current of 50 Amps, when running coils coflnected in 230 v d.c. supply with four field are then reconnected in two series. The fdafield coils Assuming flux / parallel grollps of two coils in series, - exciting current and lcad pole to be proportional to the of the speed' Find the t*rque prop*rticnar to the square nfiwspeedandarmatureculTentt \2, a) d.L', il]achines Iliscuss the foflowing tests on ii ii) b) Hopkinson's test' D.C' resistance test r- transformersDiscuss the forlowing rest on o i}sumpener,sBack-to-backtest. ii) PolaritY test' ++++ 3$1/1212016/5480 (4)

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