basic electrical lab

8/10/2019 basic electrical lab

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+P%#M(! 1: #ntrod,ction to ario,s "asic #nstr,ments o.

lectrical 'cience

&#M: Intro"#ction to $ario#% Ba%ic In%tr#ment% o& Electrical Science

)"JC!#/: Intro"#ction to $ario#% S#ppl S%tem%7 8mmeter7 9oltmeter7

5attmeter7 Ener! meter7 Tachometer7 4heo%tat7 Loa"in! e$ice%7 Tran%&ormer.

&PP&%&!' %#%D: emon%tration o& $ario#% in%tr#ment% lie 8mmeter7

9oltmeter7 5attmeter7 Ener! 0eter7 Tachometer7 4heo%tat7 9ario#% Capacitor%7 9ario#%

4e%i%tor%7 8C an" C oer S#ppl.

!)%3 )* +P%#M(!:

&MM!%

8mmeter i% emploe" &or mea%#rin! o& c#rrent in a circ#it an" connecte" in %erie% in the

circ#it. 8% ammeter i% connecte" in %erie%7 the $olta!e "rop acro%% ammeter terminal% i%

$er lo. Thi% re,#ire% that the re%i%tance o& the ammeter %ho#l" be a% lo a% po%%ible.

The c#rrent coil o& ammeter ha% lo c#rrent carrin! capacit herea% the c#rrent to be

mea%#re" ma be ,#ite hi!h. So &or protectin! the e,#ipment a lo re%i%tance i%

connecte" in parallel to the c#rrent coil an" it i% non a% %h#nt re%i%tance

'



&nalo4 &mmeter

/)$!M!%

(a) 9oltmeter i% emploe" to mea%#re the potential "i&&erence acro%% an to point%

o& a circ#it. It i% connecte" in the parallel acro%% an element in the circ#it. The

re%i%tance o& $oltmeter i% ept $er hi!h b connectin! a hi!h re%i%tance in %erie%

o& the $oltmeter ith the c#rrent coil o& the in%tr#ment. The act#al $olta!e "rop

acro%% the c#rrent coil o& the $oltmeter i% onl a &raction o& the total $olta!e

applie" acro%% the $oltmeter hich i% to be mea%#re".

&nalo4 oltmeter

5&!!M!%

The mea%#rement o& real poer in 8C circ#it% i% "one b #%in! an in%tr#ment #%in!

5attmeter. The real poer in 8C circ#it% i% !i$en b expre%%ion



9I co% Φ

here7 co% Φ i% poer &actor.

8 attmeter ha% to coil%7 namel7 c#rrent coil an" pre%%#re coil. The c#rrent coil (CC) i%

connecte" in %erie% ith the loa" an" the pre%%#re coil (C) i% connecte" acro%% the loa".5att meter% are a$ailable in "#al ran!e &or $olta!e% a% ell a% &or c#rrent

#nternal Cic,it o. 5attmeter 5attmeter

(%G3M!%

Ener! meter i% an in%tr#ment hich i% #%e" to mea%#re the con%#mption o& electric

ener! in a circ#it (C or 8C). It mea%#re% ener! in 5h. The e%%ential "i&&erence

beteen a ener! meter an" a attmeter i% that the &ormer i% &itte" ith %ome tpe o& re!i%tration mechani%m here b all the in%tantaneo#% rea"in!% o& poer are %#mme"

o$er a "e&inite perio" o& time herea% the latter in"icate% the $al#e at partic#lar in%tant

hen it i% rea".

ner4y Meter

!&C)M!%



Tachometer i% an in%tr#ment to mea%#re the %pee" in (re$ol#tion% per min#te (r.p.m.)).The

%pee" o& a rotatin! %ha&t i% mea%#re" b in%ertin! the tapere" pro;ecte" part o& the

tachometer into the tapere" hole in the rotatin! %ha&t %pee" o& hich i% to be mea%#re".

!achometer

%)'!&!

4heo%tat% are ma"e #p o& hi!h re%i%ti$it material7 lie7 nicel-chromi#m iron allo

clo%el o#n" o$er a circ#lar t#be. The%e are a$ailable both in %in!le t#be an" "o#ble

t#be. Inter-t#rn in%#lation i% pro$i"e" to a$oi" %hort circ#itin! o& t#rn%. The t#be o&

rheo%tat i% ma"e o& in%#latin! material7 lie a%be%to%. The%e are emploe" at place% here

re%i%tance o& a circ#it i% to be $arie" itho#t breain! the circ#it.

$)&D#(G D/#C'

The mo%t commonl #%e" loa"in! "e$ice% are (1) lamp Ban (2) loa"in! 4heo%tat. Lamp

Ban loa" con%i%t% o& n#mber o& lamp% connecte" to &orm a loa". The%e are %#itabl

connecte" an" controlle" b a no. o& %itche%. The %itche% are pro$i"e" in a manner %o

that it %ho#l" be po%%ible to %itch on an re,#ire" no. o& lamp% at a time.



8 loa"in! rheo%tat tpe o& loa" con%i%t% o& no. o& i"entical re%i%ti$e element%. The%e

element% are connecte" in %erie% or parallel. The rheo%tat i% ma"e #p o& hi!h re%i%ti$it

material %#ch a% lie nicel-chromi#m. The element% o& the loa" can be "e%i!ne" to tae

187 28 or 8 o& c#rrent.

$oadin4 %heostat

/&%)#' 'PP$3 '3'!M

(a) &6C s,pply systems: There are to tpe% o& %#ppl.

(i) 'in4le phase-270/: In thi% %%tem e ha$e to ire%7 one i% non a%

pha%e/line an" the other i% ne#tral. 9olta!e beteen them i% 2'* 9.

(ii) !hree phase - 800 / 9line to line): In hi% %%tem e ha$e three ire%7 one &or

each pha%e or line. In ca%e the &o#rth ire i% there it i% ne#tral. 5hile $olta!e

beteen to pha%e%/line% i% ** 97 beteen an pha%e/line an" ne#tral it i%

2'* 9.

9b DC ',pply 'ystem

There are to tpe o& .C %#ppl %%tem

(i)<rom batter: 5e #%e recti&ier% &or 9 or 129 .C %#ppl c#rrent.

(ii)<rom !enerator

6



DC ',pply &C ',pply

M$!#M!%

0#ltimeter i% a mea%#rin! in%tr#ment #%e" to mea%#re the c#rrent 7$olta!e an"

re%i%tance.The%e can be #%e" to tro#ble%hoot man electrical e,#ipment% %#ch a%

"ome%tic appliance%7poer %#pplie% etc.

!%&('*)%M% : 8 tran%&ormer i% a %tatic "e$ice hich con%i%t% o& to or more

%tationar electric circ#it% interline" b a common ma!netic circ#it &or the p#rpo%e o&

tran%&errin! electrical ener! beteen them. The tran%&er o& electric ener! tae% place

&rom one circ#it to another circ#it itho#t chan!e in &re,#enc. Tran%&ormer ma be &or

%teppin! #p $olta!e &rom lo to hi!h or %teppin! "on $olta!e &rom hi!h to lo.

3



'in4le Phase !rans.ormer

&,to !rans.ormer

%*%(C'

Boo%

1.=Electrical Science= b >. B. ?#pta

2. @8 Text boo o& Electrical Technolo!= b B. L. There;a 9ol-11

'.=Electrical En!ineerin! <#n"amental%= b el Toro

.=Electric Circ#it%= b >ame% Nel%on (ear%on p#blication)

.=Ba%ic Electrical En!!.= B C A#l%hre%htha7 T0ill.

%$’s

1. .bri!hth#b.com

2. .allabo#tcirc#it%.com

'. .ho%t#&&or%.com

. .nptel.iitm.ac.in

http://www.brighthub.com/

http://www.allaboutcircuits.com/

http://www.howstuffworks.com/

http://www.nptel.iitm.ac.in/







)bsered /al,es

911*9

92*9

929

91*9

911*9

929

I' I'+ I'++

C&$C$&!#)(':

I' @(Hb%er$e") I'GI'

I' @ (Calc#late")(b %ol$in! #%in! A9L)

J Error(Hb%er$e" 9al#e-Calc#late" 9al#e)/Calc#late" 9al#e

%'$!:

The percenta!e error i% &o#n" to beFFJ.

D#'C''#)(:

The J error i% &o#n" to be in the ran!e ithin 1*J.The percenta!e error i% "#e to

ob%er$ational error%7 tolerance error%7 calibration o& in%tr#ment%7 etc. oe$er7

%#perpo%ition theorem cannot be applie" to non-linear netor an" netor containin!

onl "epen"ent %o#rce%.

C)(C$'#)(:

The %#perpo%ition theorem i% $eri&ie".

%*%(C':

Boo%:

1. <#n"amental% o& Electrical en!ineerin! b 8%h&a, #%ain.

2. 8 Textboo o& Electrical Technolo! b B.L There;a.

'. Electrical Science b >. B. ?#pta

. =Ba%ic Electrical En!!.= B C A#l%hre%htha7 T0ill.

%$':

1. .bri!hth#b.com


'. .ho%t#&&or%.com

. .nptel.iitm.ac.in

$&" !!)%#&$'

12











1. 5hat are the a"$anta!e% an" "i%a"$anta!e% o& #%in! %#perpo%ition Theorem

2. 5h %#perpo%ition theorem i% not applie" to non-linear circ#it%

'. Can %#perpo%ition theorem be applie" to circ#it ha$in! 8.C %o#rce% I& e%7 then hatill be it% re,#irement%

. o can %#perpo%ition theorem be applie" to netor containin! both in"epen"entan" "epen"ent %o#rce%

+P%#M(! 7: / eri.y !heenin !heorem and .ind o,t

!heenin’s ;,ialent circ,it ,sin4 DC 'o,rces

&#M : To $eri& The$enin Theorem an" &in" o#t The$enin+% E,#i$alent circ#it #%in! C

So#rce%.

)"JC!#/: To appl the principle o& The$enin Theorem &or electrical netor

containin! in"epen"ent C %o#rce% an" to &in" o#t The$enin+% E,#i$alent circ#it.

&PP&%&!': i!ital 0#lti-meter7 oer S#ppl7 4e%i%tance (ire o#n")7

Connectin! 5ire%

!)%3 )* +P%#M(!:

Sometime%7 e i%h to "etermine the re%pon%e in a %in!le loa" re%i%tance in a netor.

The$enin Theorem enable% #% to replace the remain"er o& the netor b a %imple

e,#i$alent circ#it. eterminin! re%pon%e in the loa" re%i%tance7 then become% ea%ier. The

#%e o& The$enin Theorem i% %peciall $er help&#l an" time %a$in! hen e i%h to &in"

the re%pon%e &or "i&&erent $al#e% o& loa" re%i%tance. The$enin Theorem %tate% that c#rrent

thro#!h a loa" re%i%tance connecte" acro%% an to point% o& an acti$e netor can be

obtaine" b the &orm#la:

IL9th/(4 thG4 L)

1'



5here 9th i% the open circ#it $olta!e at the terminal% o& 4 L hen 4 L i% "i%connecte" an"

4 th i% the e,#i$alent re%i%tance $iee" &rom the o#tp#t terminal% hen all the %o#rce%

replace" b their internal re%i%tance onl(%hort circ#it the $olta!e %o#rce%).

P%)CD%:

1. Connect the C poer %#ppl to re%i%tance 41. 8";#%t $olta!e o& %#ppl to 1*9.

2. Connect another C %#ppl to re%i%tance 42. 8";#%t $olta!e to 9.

'. No remo$e the re%i%tance 4 L an" mea%#re 9th (open circ#it $olta!e) b %ettin!

meter in ran!e * to 2*9 .

. 4emo$e both the %o#rce% . Set o#r meter to mea%#re the re%i%tance in h#n"re"%

o& ohm% ran!e. Calc#late 4th

. No the The$enin+% e,#i$alent circ#it i% a% in &i!#re.

)"'%/&!#)( !&"$:

Calc#late" 9al#e%

9th 4 th IL

Hb%er$e" 9al#e%

9th 4 th IL

C&$C$&!#)(':

IL9th /(4 thG4 L)

5here 9th i% the open circ#it $olta!e at the terminal% hen "i%connecte"7 4 th i% the

e,#i$alent re%i%tance $iee" &rom the o#tp#t terminal% hen all the %o#rce% are replace"

b their internal re%i%tance. IL i% the c#rrent thro#!h re%i%tance 4 L.

Percenta4e rror< =9)bsered-Calc,lated>Calc,lated?@100

The percenta!e error i% to be &o#n" &or the c#rrent &loin! in the loa" re%i%tance.

1



%'$!:

The percenta!e error i% &o#n" to beFFJ.

D#'C''#)(:

The J error i% &o#n" to be in the ran!e ithin 1*J.The percenta!e error i% "#e toob%er$ational error%7 tolerance error%7 calibration o& in%tr#ment%. 0oreo$er7 it can be %een

that The$enin Theorem can+t be applie" to netor containin! onl "epen"ent %o#rce%.

C)(C$'#)(:

The The$enin Theorem i% $eri&ie" an" the The$enin+% e,#i$alent circ#it i% obtaine".

.

%*%(C':

.Boo%

1.=Electrical Science= b >. B. ?#pta

2. @8 Text boo o& Electrical Technolo!= b B. L. There;a 9ol-11

'.=Electrical En!ineerin! <#n"amental%= b el Toro

. @8 Text boo o& Electrical Technolo!= b B. L. There;a 9ol-1

.=Ba%ic Electrical En!!.= B C A#l%hre%htha7 T0ill.

%$’s

1. .bri!hth#b.com


'. .ho%t#&&or%.com

$&" !!)%#&$'

1. 5hat are the a"$anta!e% an" "i%a"$anta!e% o& #%in! The$enin Theorem

2. 5h The$enin Theorem i% not applicable to non-linear circ#it%

'. Can The$enin Theorem be applie" to circ#it ha$in! 8.C %o#rce% I& e%7 then hat i%

the "i&&erence in #%in! C %o#rce%

1









+P%#M(! 8: !o eri.y MaAim,m Power !rans.er !heorem

.or DC so,rce

&#M: To $eri& 0axim#m oer Tran%&er Theorem &or a C %o#rce.

)"JC!#/: To #n"er%tan" the concept o& 0axim#m oer Tran%&er Theorem to

the netor con%i%tin! o& a &ixe" internal re%i%tance 4 S an" a $ariable loa" re%i%tance 4 L

an" i& maxim#m poer i% "ran b the netor then it i% to be pro$e" that 4 L 4 S.

&PP&%&!': one &ixe" re%i%tor7 one $ariable re%i%tor7 "i!ital m#lti-meter7 C oer

%#ppl7 connectin! ire%.

!)%3 )* +P%#M(!::Thi% theorem i% applicable &or analDin!

comm#nication netor%. 8ccor"in! to thi% theorem=8 re%i%ti$e loa" ill "ra the

maxim#m poer &rom a netor hen the loa" re%i%tance i% e,#al to the re%i%tance o& the

netor a% $iee" &rom it% o#tp#t terminal%7 ith all ener! %o#rce% remo$e" lea$in!

behin" their internal re%i%tance%.= I& 4 L i% the loa" re%i%tance connecte" acro%% terminal% a

an" b hich con%i%t o& $ariable C %#ppl an" internal re%i%tance i% 4 S7 then accor"in! to

thi% theorem7 the loa" re%i%tance ill "ra maxim#m poer hen it i% e,#al to 4 S i.e. 4 L

4 S.

8n" the maxim#m poer "ran /2oc>8 % L

5here7 9oc i% the open circ#it $olta!e at the terminal% &rom hich 4 L i% "i%connecte".

The $ariable re%i%tor taen %ho#l" be lar!er than &ixe" re%i%tor. Then onl poer can be

calc#late".

1



P%)CD%:

1. Connect the circ#it a% %hon in <i!#re.

2. 0ea%#re the $al#e o& loa" c#rrent (IL) &or "i&&erent (%#itable) $al#e% o& loa" re%i%tance

an" recor" them in ob%er$ation table. B %#itable $al#e mean% that the $al#e o& 4 L %ho#l"

be e,#al to7 more than an" le%% than 4 S.

'. 4epeat %tep 2 &or "i&&erent $al#e o& %#ppl $olta!e (9%).

. 8l%o note "on the rea"in! in $oltmeter connecte" acro%% 4 L.Let it be 9.

. Calc#late the $al#e o& poer accor"in!l. Ko# ill notice that the poer !oe% on

increa%in! a% 4 L i% increa%in! an" a&ter &e ob%er$ation% it !oe% on "ecrea%in!.

. Note "on the maxim#m poer an" at that point calc#late the $al#e o& 4 L. Thi% 4 L

%ho#l" be e,#al to 4%.

6. ra a ?raph Beteen L an" 4 L.

)"'%/&!#)( !&"$

S.No S#ppl

9olta!e(9S)

IL(Loa"

C#rrent)

9(9olta!e) 4 L9/IL IL24 L

C&$C$&!#)(4 L9/IL

IL2 4 L

Note the maxim#m poer point an" hence "etermine the re%i%tance 4 L. Thi% 4 L i%

comparable ith 4 S. The%e come o#t to be %ame.

%'$!:

The maxim#m poer tran%&er theorem i% $eri&ie" a% 4 L4 S

D#'C''#)(It can be analDe" that at maxim#m poer7 the $al#e o& loa" re%i%tance i% e,#al to

internal re%i%tance.

C)(C$'#)(

16



+P%#M(! B: !o st,dy %-$-C series circ,it and draw its

phasor dia4ram

&#M : To %t#" 4-L-C %erie% circ#it an" "ra it% pha%or "ia!ram.

)"JC!#/: To %t#" the 8C 4-L-C %erie% circ#it an" analDe the pha%e

relation%hip beteen $olta!e an" c#rrent.

&PP&%&!': 8mmeter (*-18)7 4e%i%tor7 In"#ctor an" Capacitor7 9ariac7 Connectin!

5ire% an" i!ital 0#lti-meter.

!)%3 )* +P%#M(!: Con%i"er an 8C circ#it containin! re%i%tance o& 4

ohm%7 in"#ctance o& L henrie% an" capacitance o& C &ara"% connecte" in %erie%7 a% %hon

in circ#it "ia!ram. Let the c#rrent &loin! thro#!h the circ#it be o& I ampere an" %#ppl

&re,#enc be & D.

(a) 9olta!e "rop acro%% re%i%tance 9r I4 in pha%e ith I.

(b) 9olta!e "rop acro%% in"#ctance 9l L lea"in! I b ra"ian% or **.

(c) 9olta!e "rop acro%% capacitance7 9c I/ C la!!in! behin" I b ra"ian or **.

9l an" 9c are 13** o#t o& pha%e ith each other (or re$er%e in pha%e)7 there&ore7 hen

combine" b parallelo!ram the cancel each other. The circ#it can either be e&&ecti$el

in"#cti$e or capaciti$e "epen"in! #pon hich $olta!e "rop ( 9l or 9c) i% pre"ominant.

Let #% con%i"er the ca%e hen 9l i% !reater than 9c.

1



ha%e an!le beteen $olta!e an" c#rrent i% !i$en b:-

9l 9c /9r.

oer &actor o& the circ#it i% !i$en b:-

4/O 4/

oer con%#me" in the circ#it7 IP4 or 9I co% Φ.

P%)CD%:

1. Connect the circ#it a% %hon in the circ#it "ia!ram.

2. 0ea%#re the $olta!e %#pplie" b $ariac (91).

'. 0ea%#re the circ#it c#rrent (I) #%in! 8C ammeter.. Note "on the $olta!e "rop acro%% 47 L an" C b "i!ital m#lti-meter.

. Chan!e the inp#t $olta!e an" then a!ain note "on the $olta!e "rop (at lea%t rea"in!%)

. ra the pha%or "ia!ram beteen 9l 7 9c 7 an" 9r an" calc#late the pha%e.

)"'%/&!#)( !&"$

9i 9r 9L 9c I8 4 QL QC O Co%

C&$C$&!#)('

1. 4 9r/I

2. QL 9L/I

'. Qc 9C/I

. Cos = R/Z

. O

. ra a pha%or "ia!ram %hoin! $olta!e beteen 9r7 9L an" 9c an" calc#late it% pha%e

an!le.

%'$!:

The $al#e o& O i% RR.. an" the $al#e o& < (pha%e an!le) an" poer &actor i% RRR

D#'C''#)(

The 4LC %erie% circ#it ha% been analDe" an" it can be pre"icte" that the circ#it ha%

lea"in! poer &actor. The main preca#tion to be taen hile per&ormin! the experiment i%

that the $al#e o& re%i%tance %ho#l" be %mall otheri%e re%onance ill tae place.

2*



%*%(C'


2. 8 Textboo o& Electrical Technolo! b B. L. There;a.

'. Electrical Science b >. B. ?#pta

. =Ba%ic Electrical En!!.= B C A#l%hre%htha7 T0ill.

%$':

1. .nptel.iitm.ac.in

2. .electronic%-t#torial%.%/"ccirc#it%

'. .openboopro;ect.net

6 .mhhe.com

. .opamp-electronic%.com

$&" !!)%#&$'

1. 5hat "o o# #n"er%tan" b the term poer &actor in re&erence to 8C circ#it% .

2. 5hat i% the importance o& poer &actor

'. 5hat "o o# mean b a la!!in! poer &actor

. 5hat "o o# mean b a lea"in! poer &actor

21


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+P%#M(! : Meas,rement o. ener4y and calibration o.

'in4le Phase ner4y Meter with 5attmeter

&#M: 0ea%#rement o& ener! b an ener!meter an" to calibrate a %in!le pha%e ener!

meter ith attmeter.

)"JC!#/: In thi% experiment o#r ob;ecti$e i% to calibrate the ener! meter ith a

%tan"ar" attmeter an" hence calc#late the error beteen act#al ener! con%#me" an"

recor"e" ener!.

ner4y Meter

&PP&%&!':

1. %in!le pha%e in"#ction tpe Ener! meter (*-87 2* 97 2**-1***-'**)

2. mo$in! Iron 5attmeter ('**97 1*8).

'. loa"in! 4heo%tat (2.57 2*9).

. 0I ammeter (*-8).. 0I 9oltmeter (*-'**9)

. Stop 5atch.

!)%3 )* +P%#M(!:

22



Ener! meter i% an in%tr#ment hich mea%#re% electrical ener!. It i% al%o non a% att

ho#r (5h) meter. It i% an inte!ratin! meter. There are %e$eral tpe% o& ener! meter%.

Sin!le pha%e in"#ction tpe ener! meter% i% $er commonl #%e" to mea%#re electrical

ener! con%#me" in "ome%tic an" commercial in%tallation%. Electrical ener! i% mea%#re"

in ilo att ho#r% (5h) b the%e ener! meter%.

In thi% experiment the p#rpo%e i% to calibrate the ener! meter. Thi% mean% e ha$e to

&in" o#t the error/ correction in the ener! meter rea"in!%. Thi% calibration i% po%%ible

onl i& %ome other %tan"ar" in%tr#ment i% a$ailable to no the correct rea"in!.

5attmeter:- 5attmeter i% an in%tr#ment hich mea%#re% in%tantaneo#% poer

con%#me" b a circ#it . It con%i%t% o& to coil%:-

1. <ixe" coil7 "i$i"e" in to part% i% connecte" in %erie% ith loa" an" pro"#ce% a

&l#x proportional to the c#rrent.

2. 0o$able coil i% %#%pen"e" on the pi$ot an" ;eele" bearin!%7 pro"#ce% the &l#x

proportional to the $olta!e acro%% the loa". e&lection o& the pointer i% the re%#lt

o& the chan!e in the m#t#al in"#ctance beteen the &ixe" an" the mo$in! coil%.

P%)CD%:

1. Connect the circ#it a% %hon in &i!#re an" appl a rate" con%tant 8C $olta!e.2. Sitch on one o& the loa"%.

'. 4ecor" the time taen &or 1* re$ol#tion% o& the "i%c o& the ener! meter ith the

help o& %top atch.

. Tae $oltmeter7 ammeter an" attmeter rea"in!%.

. 4epeat &or more n#mber o& rea"in!% ( rea"in!%) &or "i&&erent loa"%.

. 4ecor" the rea"in!% a% per table.

6. Note the m#ltiplication &actor o& the attmeter.

2'



)"'%/&!#)( !&"$

4e$ol#tion% per 5h 2**

I 8 oer in

att% ()

Time re,#ire" &or

1* re$ol#tion%

(%ec%)

8ct#al ener! b

attmeter E

rea"in! in attmeter

x m#ltiplin! &actor

4ecor"e"

ener! h b

ener!

meterNo. o&

re$ol#tion% /

2**

J

error

C&$C$&!#)(1. Ener! b attmeter attmeter rea"in! x m#ltiplin! meter &actor xtime &or 1*

re$ol#tion%

2. Ener! b ener! meter (No. o& 4e$ol#tion% / 2** (in 5h)

'. Jerror (E b attmeter E b ener! meter) 1** / E b attmeter.

%'$!:

The J error i% &o#n" to be RR.J.

D#'C''#)(:- The %in!le pha%e ener! meter i% calibrate" ith attmeter b

$arin! the loa"% an" it can be &o#n" that the percenta!e error beteen act#al an"

recor"e" ener! i% $er le%%.

%*%(C'

Boo%:


2. 8 Textboo o& Electrical Technolo! b B. L There;a.

'. @Ba%ic Electrical En!!.= B C A#l%hre%htha7 T0ill.

%$':

2






. .mhhe.com


$&" !!)%#&$'

1. 5hat "o o# mean b calibration o& an in%tr#ment

2. 5here are the in"#ction tpe ener! meter% #%e"

'. o man coil% exi%t an" hat are their &#nction% in an in"#ction tpe ener! meter

. o man terminal% "oe% an ener! meter ha$e

+P%#M(! : !o per.orm open circ,it test and short circ,it

test on sin4le phase trans.ormer

2













&#M : To per&orm open circ#it te%t an" %hort circ#it te%t on a %in!le pha%e tran%&ormer.

)"JC!#/: To per&orm open circ#it an" %hort circ#it te%t% an" calc#late the

e,#i$alent circ#it parameter% C# lo%%e% an" Iron lo%%e%.

&PP&%&!': Sin!le pha%e Tran%&ormer (298)7 8C 8mmeter (*-1* 8) 8C

$oltmeter (*-'** 9)7 5attmeter (1*87 '**9)7 Connectin! lea"% 7 9ariac(2'*/26*97 2* 8).

!)%3 )* +P%#M(!:

The per&ormance o& a tran%&ormer can be calc#late" on the ba%i% o& it% e,#i$alent circ#it

hich contain% &o#r main parameter%7 the e,#i$alent re%i%tance 4 *1 a% re&erre" to primar

(or %econ"ar 4 *2)7 the e,#i$alent leaa!e reactance Q*1 a% re&erre" to primar. The%e

con%tant% or parameter% can be ea%il "etermine" b to te%t%7 i.e. open circ#it te%t an"

%hort circ#it te%t. The%e are $er economical an" con$enient7 beca#%e the &#rni%h the

re,#ire" in&ormation itho#t act#all loa"in! the tran%&ormer.

The p#rpo%e o& the )pen CEt6 !est i% to "etermine no loa" lo%% or core lo%% an" no loa"

I* hich i% help&#l in &in"in! Q* an" 4 *. Hne in"in! o& the tran%&ormer #%#all hi!h

$olta!e in"in! i% le&t open an" the other i% connecte" to it% %#ppl o& normal $olta!e

an" &re,#enc. 8 attmeter (5)7 9oltmeter (9) an" ammeter (8) are connecte" in the lo

$olta!e in"in!7 i.e.7 primar in"in! in the pre%ent ca%e. 5ith normal $olta!e applie" to

the primar7 normal &l#x ill be %et#p in the core7 hence normal iron lo%%e% ill occ#r

hich are recor"e" b the attmeter. 8% in the primar no loa" c#rrent I* i% %mall7 C#

lo%% i% ne!li!ibl %mall in primar an" nil in %econ"ar. ence7 the attmeter rea"in!

repre%ent% practicall the core lo%% #n"er no loa" con"ition.

<or short circ,it test7 one in"in! #%#all the lo $olta!e in"in!7 i% %hort- circ#ite" b a thic con"#ctor (or thro#!h an ammeter hich ma %er$e the a""itional p#rpo%e o&

in"icatin! rate" loa" c#rrent).

8 lo $olta!e (#%#all to 1*J o& normal primar $olta!e) at correct &re,#enc i%

applie" to the primar an" i% !ra"#all an" ca#tio#%l increa%e" till &#ll- loa" c#rrent i%

&loin! both in primar an" %econ"ar (a% in"icate" b the re%pecti$e ammeter%).

2



Since7 in thi% te%t7 the applie" $olta!e i% a %mall percenta!e o& the normal $olta!e7 the

m#t#al &l#x pro"#ce" i% al%o a %mall percenta!e o& it% normal $al#e. ence7 core lo%%e%

are $er %mall ith the re%#lt that the attmeter rea"in! repre%ent% the &#ll loa" C# lo%%

or i2 4 lo%% &or the hole tran%&ormer7 i.e. %#m o& both primar an" %econ"ar C# lo%%e%..

The e,#i$alent impe"ance o& the tran%&ormer #n"er %hort- circ#it con"ition7 i& 9%c i% the

$olta!e re,#ire" to circ#late rate" loa" c#rrent%7 i% then !i$en b O *1 9%c/I1.

P%)CD%:

)P( C#%C#!:-

1. Sitch on the %#ppl7 increa%e the %#ppl in an or"erl manner (rate" $olta!e) to

298 o& tran%&ormer.Thi% te%t i% per&orme" on lo $olta!e in"in! an" hi!h

$olta!e in"in! i% open.

2. Note "on the rea"in!% o& attmeter7 $oltmeter an" ammeter.

'. Comp#te the $al#e o& co% 7 4 * an" Q*.

')%! C#%C#!:-

1. <or %hort circ#it te%t %hort the %econ"ar in"in!.Thi% te%t i% per&ome" on hi!h

$olta!e in"in!7lo $olta!e in"in! i% %hort circ#ite".

2. Increa%e the $olta!e applie" %lol %o that the c#rrent &loin! in the tran%&ormer

in"in! e,#al% the rate" $al#e.

'. 4ecor" the rea"in!% o& ammeter7 $oltmeter an" attmeter hich corre%pon" to

%hort- circ#it c#rrent7 corre%pon"in! applie" $olta!e an" poer ith &#ll loa"

c#rrent &loin! #n"er %hort circ#it con"ition re%pecti$el.

. Comp#te the $al#e o& %hort circ#it impe"ance an" re%i%tance.

)"'%/&!#)( !&"$

<or Hpen- Circ#it te%t:-

26

91 I* 5 co% Q* 4 *



C&$C$&!#)(':-

591 I* co%

There&ore7 Q* 91/ I 7 4 * 91/ I

5here I I* co% 7 I I* %in

)"'%/&!#)(':-

<or Short Circ#it te%t:-

C&$C$&!#)(

<or Short Circ#it Te%t:-

5 I P4 *1

4 *1 5/IP

O*1 9/ I

Q*12 (O*1P- 4 *1P)

%'$!:The C# lo%% i% obtaine" to RRR5 an" iron lo%% i% RRR5.

23

9 I 5 O*1 Q*1 4 *1



D#'C''#)(: The open circ#it an" Short circ#it te%t ha$e been per&orme" an"

$ario#% parameter% lie 4 *7 Q*7 O*1 an" Q*1 are calc#late" an" lo%%e% o& tran%&ormer i.e.

iron an" copper lo%% can be "etermine".

%*%(C'

Boo%:



'. Ba%ic Electrical En!!.- B C A#l%hre%htha7 T0ill.

%$':




6 .mhhe.com


$&" !!)%#&$'

1. 5h in"irect te%tin! o& lar!e %iDe tran%&ormer% i% nece%%ar

2. 5hen a tran%&ormer i% ener!iDe" hat tpe% o& lo%%e% occ#r in the ma!netic &rame

o& the tran%&ormer

'. 5hat "o o# #n"er%tan" b all "a e&&icienc o& a tran%&ormer

. 5hat tpe o& lo%%e% are i!nore" in the %hort circ#it te%t on a tran%&ormer

+P%#M(! F: $oad test on a sin4le phase trans.ormer and

calc,late re4,lation and e..iciency

&#M : er&orm a loa" te%t on a %in!le pha%e tran%&ormer an" "etermine it% re!#lation an"

e&&icienc.

2













&PP&%&!': Sin!le pha%e Tran%&ormer 2987 8C 9oltmeter (*-'** 9)7 8C

ammeter (*-1*8)7 attmeter (#nit p&7 *-1* 87 *-'**9)7 Connectin! ire%7 %in!le pha%e

$ariable re%i%ti$e loa".

!)%3 )* +P%#M(!:

$oad test: The inp#t to the tran%&ormer i% ob%er$e" ith the help o& attmeter. Let it be

51. The o#tp#t o& the tran%&ormer i% calc#late" &rom the pro"#ct o& the $olta!e (9) an"

c#rrent (I) in the %econ"ar o& the tran%&ormer. The loa" i% taen a re%i%ti$e an" there&ore

poer &actor i% #nit.

ence M (e&&icienc) o& tran%&ormer o#tp#t/ inp#t x 1**

(9 I) x 1**/1

/olta4e %e4,lation: 5ith the increa%e in loa" on the tran%&ormer7 there i% a chan!e in it%

terminal $olta!e. The $olta!e &all% i& the loa" poer &actor i% la!!in!. It increa%e% i&

poer i% lea"in!. The chan!e in %econ"ar terminal $olta!e &rom &#ll loa" to no loa"7

expre%%e" a% a percenta!e o& &#ll loa" $olta!e i% calle" the percenta!e $olta!e re!#lation

o& the tran%&ormer. I& E i% the no loa" terminal $olta!e an" 9 i% the &#ll loa" terminal

$olta!e then J 4e!#lation (E- 9) x 1** / 9.

P%)CD%:

1. Connect the circ#it a% %hon in <i!#re.

2. 8ppl &#ll loa" an" note "on the rea"in!% o& attmeter7 $oltmeter7 an" ammeter.

'. ecrea%e the loa" an" note "on the rea"in!%.

. Calc#late e&&icienc an" re!#lation ith rate" an" hal& rate" loa".

)"'%/&!#)( !&"$

5l 9l I2 92

'*



C&$C$&!#)(

M (92 I2 / 51) 1**

J 4e! (E 9) 1** / 9 here E i% %econ"ar no loa" $olta!e

D#'C''#)(:- B calc#latin! the $olta!e re!#lation the &i!#re o& merit hich

"etermine% the $olta!e characteri%tic% o& a tran%&ormer can be "etermine". B act#al

loa"in! tran%&ormer e&&icienc can+t be "etermine" ith hi!h preci%ion %ince the lo%%e%

are o& the or"er o& onl 1 to J. The be%t an" acc#rate metho" o& "eterminin! the

e&&icienc o& a tran%&ormer o#l" be to comp#te lo%%e% &rom open circ#it an" %hort circ#it

te%t an" then "etermine the e&&icienc.

%*%(C'

Boo%:



'. Electrical Science b >. B. ?#pta.

. Electrical En!ineerin! <#n"amental% b el Toro.

. =Ba%ic Electrical En!!.= B C A#l%hre%htha7 T 0 ill.

%$':




. .mhhe.com

$&" !!)%#&$'

1. 5hat "oe% the rea"in! o& attmeter in"icate in ca%e o& %hort- circ#it te%t ontran%&ormer

2. o "o the copper lo%%e% $ar ith loa" on a tran%&ormer

'. 5hat i% the ma!nit#"e o& no loa" c#rrent a% compare" to &#ll loa" c#rrent

. 5hat i% the poer &actor o& a tran%&ormer #n"er no loa" con"ition

'1











. i&&erntiate beteen @all "a e&&icienc= an" @poer e&&ienc= o& a tran%&ormer.

. o an a#totran%&ormer "i&&er% &rom a to in"in! tran%&ormer

basic electrical lab

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