Page 186 - Electrician -1st Year - TT

G]úY I = I Cos 30 + II Cos 30 o Uôt± Ñ®hf ApXÕ vPôo ùPpPô
o
U UV UW
vPôhPo (star-delta starter)
3
B]ôp Cos 30 o = . vPôo CûQl©u TVuØû\ (Application
2
of star connection): BpPoú]hPoLs, Utßm
CqYô\ôL, I = 3 Iph
L T¡oUô] ¥Wôuv @TôoUoLsL°p vPôo
Øû\«p Es CûQl× ùNnVlThP êuß
CqYô\ôL JÚ NUu ùNnVlThP ùPpPô
CûQl©p úTv ªuú]ôhPj§tLô] £e¡s úTv Lô«pLs CÚdÏm.
ûXu ªuú]ôhP ®¡Rm 3 BÏm. AûNuùUuh (Assignment) : 400-V, 50Hz êuß
úTv ªu YZeLXõ u ÏßdúL JqùYôußm
ûXu ªuú]ôhPm = 3 x úTv
10 KmLs ªuRûPÙm 20mH çiPp ùLôiP
ªuú]ôhPm.
êuß JúW Uô§¬Vô] Lô«pLs ùPpPô
( ) Øû\«p CûQdLlThÓs[]. ûXu
vPôo Utßm ùPpPô CûQl©u
ªuú]ôhPjûR LQd¡PÜm.
TVuTôÓLs (Application of star and delta
connection with balanced loads) : JÚ Ød¡VUô]
TVu VôùR²p, vPôo ùPpPô CûQl×

3 úTv AûUl©p ¨ëhWp LPj§ (Neutral in 3-phase system)

úSôdLeLs: ClTôPj§u Ø¥®p ¿eLs ùT\ úYi¥V A±Ü §\uLs
•3 úTv vPôo CûQl©u ¨ëhWp ªuú]ôhPjûR ®[dÏRp
• ¨ëhWp ¨Xl©ûQl×l Tt±d áßRp.

¨ëhWp (Neutral): JÚ êuß úTv vPôo ªuú]ôhPeLs ùYdPôo áhÓj
CûQl©p vPôo ×s°Vô]Õ SÓ¨ûX ùRôûL«û] UhÓúU CkR LPj§ GÓjÕf
×s° G]Üm, SÓ¨ûX ×s°«p ùNpX úYi¥VRô¡\Õ.
CûQdLlThP LPj§ ¨ëhWp LPj§ I = I , I and I þ«u úT^ôo áhÓj ùRôûL
G]Üm LÚRlTÓ¡\Õ. (Fig 1) N U V W
BÏm.
ªuú]ôhPeLs NUUôLÜm, TÞÜm NUu
ùNnVlThPRôLÜm GkR CPeL°p
CÚd¡u\úYô AeÏ CkR ùYdPôo áhPp,
TVuTÓm GuTûR LôhÓ¡\Õ. CRu
®ûVYôL ¨ëhWp ûXu I þ²p
N
ªuú]ôhPm '0' YôÏm. (Fig 2)

¨ëhWp LPj§«p ªuú]ôhPm (Current
in the neutral conductor): SôuÏ Lm© AûUl×
vPôo CûQl©p ¨ëhWp LPj§ N B]Õ
I , I Utßm I B¡VYt±u
U V W
ªuú]ôhPeL°u áhÓj ùRôûL«û]
GÓjÕf ùNpX úYiÓm. G]úY, G]úY JÚ NUu ùNnVlThP ÑûU«p
LPj§Vô]Õ Ï±lTôL A§LThN ¨ëhWp LPj§«p ùNpÛm
ªuú]ôhPjûR GÓjÕf ùNpX úTôÕUô] ªuú]ôhPj§u A[Ü "0' BÏm.
TWl©û] ùTt±ÚdL úYiÓùUu\ GiQm ¨ëhWp LPj§ûV ¨Xl©ûQl× ùNnRp
JÚYÚdÏ HtTPXôm. B«àm CÕ (Earthing of neutral conductor): ªu]ôt\ûX
AlT¥VpX, Hù]²p êuß ÅÓLs Utßm YojRL ¨ßY]eL°u

166 TYo : GXdh¬μVu (NSQF - Revised 2022) R.T. Ex.No. 1.5.52 - 56