in single phase we get 220 volt and in three phase 4420 v
why this
second Ques= in case three phase star conection our
neutrul becom disconect what happan

3 Q=== a three phase house load and have unbalce load on
different pahse diffrent current eg phase a 7A b 8A c
5A and voltage is 440 than how calculate it total load in
kw pl give formula thanks

Answer Posted / deepakindi1

1)In single phase u measure Voltage wrt neutral ie Phase to
neutral(VN)which is phase voltage,
#In three phase if u measure voltage b/w two line terminals
ie b/w R-y or Y-B or R-B it vl b 440v even in three phase
supply if u measure voltage b/w any phase and neutral point
it vl b 220.(Vph=VL/(square Root of 3).
2)A break in the neutral conductor can however result in
wide rise of the voltages between
each phase and the star point if the three single phase
load currents deviate from the ideal
balanced condition. Depending on the degree of unbalance
between the single phase loads, in
the extreme, the three single phase voltages (phase to
neutral) could vary from as low as zero
volts, to any voltage up to the phase to phase voltage.
Irrespective of load balance, the voltages
between phases are not affected by a break in the neutral
conductor.
3) VR*IR*cos(@)+Vy*Iy*cos(@)+Vb*Ib*cos(@)

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