Answer / pankaj malhotra

The best way to minimise 3rd harmonics in the transformers
there are two ways. Either transformermer has low flux
density which is not economical and not in use or to make
atleast one winding of the transformer in delta because 3rd
harmonics are absent in delta. Since the requirement of
three phase four wire system in distribution, we commonly
use delta star winding

Answer / gunasekaran

one voltage level single earthing is recommended that is at
source for G.T generator is source it is already earthed.if
we use star we have to do the earthing so delta connection
is preferred.for distribution sending end is already earthed
at substation so HV side of the distribution transformer is
delta for LV side transformer is source so star with earthed
neutral. if two earthing is provided zoro sequence current
getting closed path so wave farm become distracted.

Answer / arvind sharswat

only most reson because i can gate 3phase and single phase with nutral in delta-star connection

Answer / aashish sharma

Delta connection is make at primary side because in delta
low harmonics(3rd,5th and 7th) produce as compare to star
while at secondary side star connection is use to provide 3
phase 4 wire system or we can say that getting singale
phase from 3 phase.

Answer / a,karthika

because we can make earthing only in star connection.if
there is an excess amount of power which can be easily
removed by earthing.Hense secondary winding is a srat
winding

Answer / vinod meshram

in my thinking we use for getting nutral only because in
delta it is never possible to get neutral.We get neutral on
secondary side for distribution perpose.

Answer / e venkat reddy

In Delta connection it requires only three wires to
transfer on power but in star it requires 4 wires to
transfer the same amount on power so we are using delta at
primary side.because availability of neutral we are using
star connection at secondary side. In delta side the zero
sequence is current also zero.

A 3 phase motor operating off 415V system is developing 20Kw at an efficiency of 0.77 and power factor of 0.73. determine:- a)the line current. b)the phase current if winding are delta connected. c)the phase voltage if winding are star connected.

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