Page 118 - Electrician -1st Year - TT

JÚ Ï±l©hP GpûXdÏs Ïû\kR úThP¬
úYôphúP´u ®û[®tÏ G§o®û[ûY
HtTÓjR CÕ N¬ùNnÕ (adjust) ùLôÓd¡\Õ.
úThP¬ úYôphúPw B]Õ JÚ Ï±l©hP
U§l©tÏ ¸r Årf£VûPkRôp N¬ ùNnÙm.
R (adjusting R ) Tô«uhPûW ‘0’ (éwVm)
2 2
¨ûXdÏ ùLôiÓ YWôUXõÚdLXôm. G]úY
CkR úThP¬dÏl T§XôL JÚ SpX ×Õ
úThP¬ûV Uôt\ úYiÓm.

Fig 2 -p LôhPlThÓs[Õ úTôp ÁhP¬u
úYûX ùNnÙm ®Rm (Working) : A Utßm B Es[ A[ÅÓL°p (meter scale) YXÕ KWj§p
Øû]Lû[ (terminals) JußPu Juß ‘0’ (éwVm) G]Üm CPÕ KWj§p LQd¡p
CûQdLlTÓm ùTôÝÕ (shorted) (U§l× APeLôÕ (infinity) ( ) G]Üm
ùR¬VôR ªuRûP R -= éwVm (0)
x ϱl©PlTh¥ÚdÏm.
EVokRThNUô] LWih AkR Ñt±p
ùNp¡\Õ. TdL CûQl× ªuRûP R (shunt
2
resistance)-I N¬ùNnÕ (adjust) ÁhPûW ØÝ
A[Ü LWih (full scale current-)-I LôhÓmT¥
ùNnVlTP úYiÓm. CÕ ØÝ A[®p
LôhÓm (full scale current ) LWih ¨ûXûV ‘0’
(éwVm) Km ( ) G] vúLXõu úUp
ϱdLlTh¥ÚdÏm. Km ÁhP¬u Øû]Ls
KmÁhP¬u vúLp JÝeLt\ º¬pXôR
(A & B terminals) §\kR ¨ûX«p CÚkRôp
CûPùY°«p (non linear) Es[RtÏ LôWQm
ÁhP¬u AûNÙm AûUl©p GkR
Gu]ùY²p ªuú]ôhPj§tÏm
LWihÓm ùNpXôÕ. G]úY ÁhPo Ã¥e
ªuRûPdÏm G§o®¡R ùRôPo × Es[RôL
LôhPôÕ, úUÛm ûPVXõu CPÕ ûL
(inverse relationship) CÚlTÕRôu. CR]Õ
TdLj§p GpûX«pXôÕ (infinity) ( ) ªuRûP
®û[Yôp '0' Es[ CPj§tÏ AÚ¡p
G]d ϱdLl Th¥ÚdÏm. CRu
®¬Yô] (expended) vúLXôLÜm, LQd¡p
ùTôÚ[ô]Õ CWiÓ úNô§dÏm
APeLôR ( ) CPj§p Es[ vúLp
Øû]LÞd¡ûP«p GpûXVt\ LQd¡p
áhPUôL CÚd¡u\Õ.
APeLôR (infinite) ªuRûP«u U§l× §\kR
Ñtß (open circuit) EûPVÕ GuTRôÏm.
Fig 3
U§l× ùR¬kR ªuRûP R -I A[dÏm
x
LÚ®«u A & B Gu\ CÚØû]LÞd¡ûP«p
CûQlTRôp PVXõp Es[ CûPlThP
(Intermediate) CPj§u Uôod¡e¡p ¨tÏm.
Km ÁhP¬u ÕpXõV A[Yô]Õ
úThP¬«u ¨ûXjRuûUûVl
ùTôÚj§ÚdÏm. ÁhP¬u Esú[ Es[
úThP¬«u úYôphúPw B]Õ £±Õ
TdL CûQl× YûL Km ÁhPo (Shunt type
£±RôL ARu TVuTôÓ ApXÕ úNªdÏm
ohmmeter) : Fig 3þp `uh YûL Km ÁhP¬u
úSWjûRf NôokÕ Ïû\¡\Õ. CmUô§¬Vô]
Nodëh TPjûRd LôhÓ¡\Õ. CkR ÁhP¬p
¨ûX«p ÁhP¬u A & B Øû]Lû[ JußPu
úThP¬ ‘E’ B]Õ, ‘0’ KªtÏ N¬ ùNnÙm
Juß úNojÕ CûQdLlTÓm ùTôÝÕ,
ªuRûP R (zero ohm, adjustment resistor R )
ØÝ A[Ü LWih (full scale current) B]Õ 1 1
ùRôPo CûQl©p CûQdLl
ªu]ÝjRd L£®]ôp (voltage drops) ÁhPo
Th¥ÚlTÕPu PMMC ÁhPo SLÚm
‘0’- I Lôi©dLôÕ. CÕ (Fig 1)-p
AûUl×m (PMMC meter movement) ùRôPo
LôhlThÓs[Õ. úYßTÓjRdá¥V TdL
CûQl©p CûQdLlTh¥ÚdÏm.
CûQl× ªuRûP ‘R ’ (shunt resistor) B]Õ
2
98 TYo : GXdh¬μVu (NSQF - Revised 2022) R.T. Ex.No. 1.3.33