Answer / dolphinopera

if the three phase
load is unbalanced (ie)
the impedance me
three phases are not
equal, a circulating
current will be
produced, hence this
current should flow
through the neutral.
otherwise the
winding will damage.

Answer / rvg

if the three phase load is unbalanced, there will be a
voltage between the common point (star system) and earthed
ground( system ground), known as Neutral shift voltage. So
if you are short circuiting these, there will be a current.

Ir+Iy+Ib=Io not Zero for unbalanced loads.

Answer / prabhu

Due to unbalance of load

Answer / pravesh

in electrial system we can sy that neutral is the return
path of the elctivity as if there is any immbalance of the
supply or unbalanced load then some current flows through
the neutal , and if the system is balanced then only no
current flows through the neutral , in single phase supply
there is no current in neutral until there is disbalance
from incoming side or the equipment is faulty.

Answer / marshal mothers

Balanced loading in 3 phase system is only achieved in
factory settings, in distribution system loads keep on
flactuating during the day hence loading keeps varying
throughout the day

Answer / ashokreddy r

In single phase systems current flows thro the neutral as
it is the return path
In three phase systems w.r.t individual phases there is
neutral current .(Ir0,Iy0,Ib0)
For balanced system Ir0+Iy0+Ib0=0
For unbalanced system Ir0+Iy0+Ib0 not equal to zero

Answer / ashok kumar saini

Due to unbalance load on 3Ph .

Answer / sumesh s l

even though the system is balanced third harmonics gets
added up.(r-phase sin3wt,y phase/b phase :sin3*(+/-120wt)
same as sin3wt.that is all harmonics component of 3 and
multiple of 3 added up...so neutral current may not be zero..
for more information mail me at sumeshsl@gmail.com or
eeo8m107@smail.iitm.ac.in

Answer / onkar singh

i think it occours only in case of unbalancing. i.e if a
suddern unbalancing of load occours then a particular
neutral to ground voltage forms that forces unbalancing
current to flow in the neutral to counteract the
unbalancing of load.

Answer / ujjwal karki

1. As per the theory, No current should be flowing in the neutral. But this is theoretically possible when the load in each phase are perfectly balanced. As the switching patterns of each loads in 3 phases are not exactly the same, some amount of neutral current is likely to flow through the neutral.

2.Another likely cause as to why there is current flowing in the neutral is due to the effect of harmonics. Lets take an example of transformer. The Hysteresis loss in transformer causes a non-sinusoidal exciting current to flow which mainly comprises of third and fifth harmonics. Since the line-line third harmonic voltage is zero, these current can only flow through the neutral wire or around the mesh winding.(If these harmonic current donot get a path to flow, the flux in transformer is not sinusoidal and the output voltage is non sinusoidal as well!!). Hence, high current might be flowing in neutral and there is even the provision of doubling the size of neutral wire to prevent its overheating.

Why is better to have a minimum ceiling voltage of 250% than 160%?

0 Answers  

How do we calculate conductor size?

1 Answers   Hero Honda,

How conventional fire alarm system works?

1 Answers  

what happen if the load connected to the induction motor is taken away? the same question for synchoronous generator in synch i think that the the exitation voltage will appear on the terminal only if so plz answer me

0 Answers   Escorts,

In the solution of load flow eqation, Newton raphson method is superior to the gauss siedal method because (a)the time taken to perform one iteration in the NR method is less when compared to GS method (b)the number of iterations required in the NR method is more compared to that in the GS method (c)the number of iterations required is dependant on the size of the system in the NR method (d)convergence characteristics of the NR mehod are not affected by the selection of the slack bus

1 Answers  

How to calcualte 1unit of current consumption?

3 Answers   Bhushan Power Steel, ITC Infotech,

What is George phenomena to start the synchronus machine?

0 Answers  

sir pls send the je exam - 2008 and other model question papers..

0 Answers  

Write down the name of 2 lady Bir Pratin of Bangladesh

0 Answers  

WHAT IS THE PARTIAL DISCHARGE TEST?

0 Answers   ME,

Why thwe Direction of Rotation of a TABLE Fan & CEILING Fan are different?

8 Answers   Wipro,

Dear all, kindly give me the details of leectrical design engineer course details/institute in hyderabad /any where in india.

1 Answers   Reliance,