QUESTIONS ASKED IN THE INTERVIEW OF SOME COMPANIES
1. What is the difference between synchronous motor vs induction
motor?Which one is better and in what respect?(Tata Motors)
2. What is the difference b/w d.c machines and induction motor?
Which one is better and why? (Tata Motors)
3. What is the power factor? ow can u improve power factor and
its app!ications? (Tata Motors)?
". What is re!ay protection? What is distance protection and
differentia! protection? (Tata Motors)
#. What r the diff. types of protection re!ays used in $enerator?
(Tata Motors)
%. &ifferent types of induction motor? (Te!! about doub!e s'uirre!
ca$e motors a!so). (Tata Motors)
(. What is )ucho!* re!ay of transformer? What is the function of the
breather of +,mer? -ee its constructions difference?(./-01)
2. ow to increase the +,mer efficiency?(3104).
5. Why +,mer is rated in 678 whi!e motor $enerator) in 6W?
(3104)
19. Tor'ue vs s!ip characteristics of 3 phase induction motor?
(Tata Motors)
11. What is the wor:in$ of 1 phase induction motor? (Tata
Motors)
12. 0apacitor and induction start of 1,ph 3.M?(8;378)
13. ow to improve the power factor of a m/c?(<T=0)
1". Wor:in$ princip!e of dc m/c both of motor and $enerator?
1#. What type of motor is used in Water pumps?
1%. What type of motor is used in in e!ectric trains?(3104)
1(. Why is the $eneratin$ fre'uency in 3ndia is #9 h*? Whi!e
that of /-8 is %9 h*? (3104)
12. What wi!! happen if a m/c of !oad rated at %9 h* is used in
3ndia? (./-01)
15. What is thyristors? 8nd its app!ications? (./-01)
29. Why do we use a diode in para!!e! to thyristor? (./-01)
21. What is free whee!in$ diode? (Tata Motors)
22. What r the necessary conditions " para!!e! operations of +,
mer> a!ternators etc? (Tata Motors)
23. 0ondition of synchroni*ation? (Tata Motors)
2". What is the resistance ran$e of 3 phase windin$ in any
motor? (Tata Motors)
2#. Tor'ue is $reater in which type of 3.M? (Tata Motors)
2%. Which type of 3.M is most!y used an why? (Tata Motors)
2(. ow do we chan$e the speed in 3.M?(T8T8 =1W?;)
22. ow do we chan$e the fre'uency of 3 ph 3.M?(T8T8
=1W?;)
25. Whi!e startin$ the motor which type of connections are
$enera!!y used? 8nd why?(T8T8 =1W?;)
39. &e!ta,star connection is used where in the transmission !ine
and why? @ive the advanta$es?(.3<&84)
31. Arom What type of connections do we $et supp!y in our
houses and why?(.3<&84)
32. ?+p!ain reactive and rea! power? 3f the reactive power
consumption of the system increases what happens to the overa!!
efficiency of the system?(.3<&84)
33. Why do we used star,de!ta connection in 3 phase 3.M?
&raw the circuit dia$ram?(4<T)
3". &escribe ThereninBs Theorem?(4<T)
3#. What is s:in effect? What is pro+imity effect?(3104)
3%. What are eddy current !osses? &escribe ysteresis !osses?
3(. &escribe 0orona effect in the transmission !ines?(3104)
32. What happens if we increase or decrease the fre'uency in
the same rated +,mer?(supp!y side)(3104)
35. ow does the wattmeter in the house wor:? ow the
bi!!in$ is done?(T8T8 -T??4)
"9. ow do we do bi!! ca!cu!ation?(.3<&84)
"1. -peed contro! is better in which motor?(.3<&84)
"2. ow does the cho:e wor: in the e!ectric tube?(T8T8
M1T1;-)
"3. What type of m/c is used in the cei!in$ fan?(T8T8
M1T1;-)
"". Why de!ta,star connection is used in the end of
transmission !ine?(T8T8 M1T1;-)
"#. What is the ma+imum efficiency a motor can have?(T8T8
M1T1;-)
"%. What is ma$netic !oc:in$> craw!in$ and huntin$ in the m/c?
(<T=0)
"(. What type of m/c is used in !athe m/c?(T8T8 M1T1;-)
"2. Why rotor of the m/c is !aminated?(T8T8 M1T1;-)
"5. What is the ma+ speed that a synchronous motor can attain?
(3104)
#9. What is the ferranti effect?(3104)
#1. What is the series trippin$ scheme and shunt trippin$
scheme?(3104)
#2. Why open armature windin$s are not used in dc m/c?
(<T=0)
#3. &ia$ram of commutation in dc m/c?(<T=0)
#". Why +,mer have more !osses than induction motors?
(T8T8 M1T1;-)
##. -ee the v/f contro! of 3.M? (T8T8 M1T1;-)
#%. Why dc series motor is not started at !i$ht !oaded
condition? (T8T8 M1T1;-)
#(. Why dc shunt motor is used in saturated re$ion? (T8T8
M1T1;-)
#2. What r re!ays> 4i$htnin$ arrestors> iso!ators and circuit
brea:ers?(<T=0)
#5. What r diff types of circuit brea:ers? &escribe them?
(<T=0)
%9. What is the diff b/w iso!ator and circuit brea:er in terms of
their operation? (<T=0)
%1. Why induction motor runs at a speed !ess than synchronous
speed? (<T=0)
%2. What is synchronous speed? (<T=0)
%3. What is the difference in the se!f e+cited and separate!y
e+cited dc $enerators?(in terms of residua! ma$netism)(T8T8
-T??4)
%". Why termina! vo!ta$e decreases when we increase the !oad
in dc shunt motor? ?+p!ain with $raph?(T8T8 -T??4)
%#. Why termina! vo!ta$e decreases when we increase the !oad
in a!ternator? ?+p!ain with $raph?(T8T8 -T??4)
%%. What type of motor do we have in the cei!in$ fan?
(.3<&84)
%(. What is the power number?(<T=0)
%2. What is master re!ay/ bac: up re!ay?(T8T8 -T??4)
%5. What are different types of motors? (T8T8 -T??4)
(9. What do u mean by T motor and 4T motor? (T8T8
-T??4)
(1. What is the difference b/w inverter and a!ternator?()?M4)
(2. ow do u char$e battery in the car? ()?M4)
(3. What is the use of dc supp!y in the power p!ant?(<T=0)
(". Why synchronous motor is not se!f startin$?(<T=0)
(#. -:etch the sin$!e !ine dia$ram of re!ay?(<T=)
(%. -:etch the sin$!e !ine dia$ram for +,mer protection?
(<T=0)
((. @ive the specifications of re!ay? What one shou!d see
before purchasin$ re!ay?(<T=0)
(2. Why do we connect current transformers in series whi!e
potentia! +,mer in para!!e! with the transmission !ine?(T8T8
=1W?;)
(5. Why do we connect !i$htnin$ arrestors near the +,mers?
(3104)
29. Why do we have path made of pebb!es near hi$h!y char$ed
!ines?(we donBt have concrete path near hi$h!y rated
transformers)(3104)
21. &raw the !ine dia$ram of bucho!* re!ay of transformers?
(<T=0)
22. Why transformer core is !aminated? (./-01)
23. What is the difference b/w carBs fan and cei!in$ fan?
(-<3&?; ?4?0T;3084-)
2". What is the wor:in$ princip!e of tube !i$ht?(-<3&?;)
2#. What is the difference b/w tab!e fan and cei!in$ fan?
(3104)
2%. Why do we have 2# 67 dc !ines in the e!ectric train?
(3104)
2(. Which motor is used in e!ectric trains? Why? (T8T8
-T??4)
22. What is the supp!y fre'uency of aerop!ane and why?
(3104)
25. What is the difference b/w power an$!e and power factor?
()?M4)
59. Why do we main !ine supp!y in the mu!tip!e of 1167 i.e
1167>2267>3367 etc?(3<&8401)
51. &efine ohmBs !aw?
52. =40 and -08&8 ?
53. &ifferent types of cab!es? (<T=0)
5". 3nsu!ations used in cab!es? (<T=0)
5#. &raw the s:etch of therma! power p!ant?(<T=0)
5%. What is the speed at which the turbine of the therma! power
runs?(<T=0)
5(. What is the ma+imum speed of the synchronous m/c
runnin$ at #9 *?(<T=0)
52. What is the efficiency of transmission !ines?(<T=0)
55. What is M1-A?T> ).T> 3@)T etc?(T0-)
199. What wi!! be the effect if we use ac instead of dc e+citer in
a!ternators?(<T=0).
191. Why motor rotates and transformer does not?
192. Why the power factor of an induction motor is !ow?
193. ?+p!ain 7/A contro! of induction motor ?
19". ?+p!ain over,f!u+ contro! of synchronous $enerator(T8T8
-T??4).
19#. What is craw!in$ and co$$in$?(3<&8401)
19%. Mention a!! protection for motors? (3<&8401)
19(. What is sin$!e phasin$? (3<&8401)
192. What is 47&T > differentiate between active and passive
transducers? (3<&8401)
195. ?+p!ain 0T/=T with circuit dia$ram?(7?&8<T8)
119. &ifferent between $raphs of 3,phase and 1,phase induction
mptors?(3-=8T)
111. Why a sin$!e cab!e is !aid over the transmission cab!e ?
(3-=8T)
112. What is the ro!e of an e!ectrica! en$ineer in an automobi!e
sector?(T8T8 M1T1;-)
113. ?+p!ain swin$ e'uation? (7?&8<T8)
11". What is binary>se!ection sortin$ :eys of rdbms >swappin$
of two numbers?(3)M)
11#. What is )4&0?(7?&8<T8)
11%. Which instrument is used to measure insu!ation ?(M)4)
11(. ?+p!ain the arran$ements of ammeter and vo!tmeter ?
(3-=8T)
112. What wi!! happen if they are connected in para!!e! and
series respective!y?(3-=8T)
115. @ive practica! e+amp!es of c!osed and open !oop systems?
(3-=8T)
129. ?+p!ain curves of over> under> critica!!y damped
osci!!ations?(3-=8T)
121. What parameters/specifications wi!! you consider for a
motor?(T8T8 M1T1;-)
122. &ifferent types of protection ?(T8T8 M1T1;-)
123. Which motor is used in train and why? (T0-)
12". ?+p!ain types of switches (!eve! contro! switches)?
12#. What is ;0 fuses?(T8T8 M1T1;-)
12%. ?+p!ain capacitance ca!cu!ation for power factor
improvement ?(800)
12(. ow wi!! you bui!d a nuc!ear power p!ant?(T0-)
122. Whci motor is used for !iftin$ operations ?(T0-)
125. 8 p!ate has three ho!es throu$h which passes ; >C >)
phases to an 3M >what wi!! be effect of motor runnin$ on p!ate?
(the answer is heatin$ >3 $uess ).What wi!! you do to reduce
heatin$?(3<&8401)
139. ow wi!! you set,up a power p!at from scratch? ?+p!ain in
terms of technica! terms?(M83<&;8)
131. ?+p!ain the wor:in$ of a power p!ant in !ay man !an$ua$e
e+p!ain everythin$ from $eneration in power p!ant to
transmission to your house?(<3T3? Mumbai)
132. &ifferent between washin$ machine and hand washin$
w.r.t c!osed and open !oop system concepts? Which is better?
(3-=8T)
133. 1f which materia! is the core of a transformer made up of?
(3-=8T)
13". ?+p!ain the circuit dia$ram of tube !i$ht?(3<&8401)
13#. What is 7,curve and inverted 7,curve?(3<&8401)
13%. What wi!! happen if ac supp!y is fed to a &0 motor and
vice,versa?
13(. 0an we reverse the connections of armature windin$ and
fie!d windin$ of dc motor and dc $enerator? 3f yes what wi!!
happen in the $iven four cases?(T8T8 M1T1;-)
132. What is =40?(<T=0)
135. What is over !oad temperature protection in induction
motor? which temperature is measured for this?(<T=0)
1"9. Mention advanta$es of 7&0?(<T=0)
1"1. Which motor is used in fan ? ?+p!ain its startin$?(T8T8
-T??4)
1"2. Which supp!y is used in train traction system? Why?
(T8T8 -T??4)
3M=1;T8<T @/3&?43<?-D..
1. Cou wonBt find the names of many companies in here> but these
'uestions cover a!most the entire !ist of companies.
2. &onBt $enera!i*e the nature of any company w.r.t the :ind of
'uestions as:ed in the previous yearE )e prepared with the entire
sy!!abus.
3. =repare the ; part very we!!.( !i:e Fte!! me somethin$ about
yourse!f?G).
". &onBt hesitate to use pen and paper to e+p!ain anythin$ to the
pane!. 3t !eaves a $ood impression and shows your confidence .
(My persona! e+perience)
#. -ome 'uestions may seem weird. -o Hust i$nore them but be
prepared for themE
%. &onBt hesitate to contact your seniors re$ardin$ 'uestions> Hob
profi!e of any company or anythin$.
(. &o not mention phrases !i:e F 3 donBt remember > 3 read it !ast
semesterGDD
2. -tudy hard this summer .
Some important topics!
1. Machines(=.-.)himbra or ).4. TheraHa)(must)
2. =ower system(7.6. Mehta.)(must)
3. -witch $ear and protection()adrinath).(must)
". &rives >topics !i:e brea:in$> motor speed contro!(Hust an overview)
(@.6.&ubey).(must)
#. 3nverters and basics of -0;.
Some HR questions generally asked…..
1. Te!! me somethin$ about yourse!f ? (most important)
2. Cour stren$th and wea:ness.
3. Te!! me about your fami!y bac:$round?
". Why have you pic:ed up e!ectrica! en$ineerin$?
#. What is your area of interest?
%. Why is a year $ap in your academics?
(. 0ase study can be as:ed (in companies !i:e 4<T > de!!oite
><oumura > @-achsD..)
2. Why do you want to Hoin this company?
5. What wi!! you do to deve!op .har:hand?(M8;/T3 )
19. 0urrent affairs !i:e 3=4D(M8;/T3).
11. &o you want to do M)8/M-?(@sach >&e!!oiteD.)
Wishing best of luck ….
For 2k7 EEE batch from the entire 2k6 EEE batch.
Com
piled by:-
Navneet kumar
(!C" #EEE 2k6$