Electrical Engineering - Three-Phase Systems in Power Applications - Discussion
Discussion Forum : Three-Phase Systems in Power Applications - General Questions (Q.No. 9)
9.
A two-phase generator is connected to two 90 
load resistors. Each coil generates 120 V ac. A common neutral line exists. How much current flows through the common neutral line?
load resistors. Each coil generates 120 V ac. A common neutral line exists. How much current flows through the common neutral line?Discussion:
63 comments Page 3 of 7.
Suryabai said:
9 years ago
Which is the correct answer? Please tell the correct option.
Palthur said:
1 decade ago
In a two phase system voltages are displaced apart from each other by 90 degree so resultant of 2 currents flow through the neutral wire which is 1.88 A.
Ali said:
9 years ago
the correct answer is (B) as:
This is a two phase system gnerator with source voltage:
Va = 120 with zero angle & Vb with angle 90 degrees, thus the nutral current is as follows
In = Va /90 + Vb / 90 = (120/_0)/90 + (120/_90) = 1.33 + j1.33 = 1.88.
This is a two phase system gnerator with source voltage:
Va = 120 with zero angle & Vb with angle 90 degrees, thus the nutral current is as follows
In = Va /90 + Vb / 90 = (120/_0)/90 + (120/_90) = 1.33 + j1.33 = 1.88.
Ali said:
9 years ago
According to me, the answer is 2.66.
Sasikumar paramasivam said:
8 years ago
The current in each phase is 120/90 = 1.33a.
For two-phase system, the resultant current at the common line is root(2) of phase current which is 1.88a.
For two-phase system, the resultant current at the common line is root(2) of phase current which is 1.88a.
Parihar said:
8 years ago
120 * 120 ÷90 * 90 = 1.77.
Naveen BM said:
8 years ago
Since it is AC we should take RMS voltage into consideration. The RMS voltage = (Peak Voltage/SquareRoot(120)).
Hence the current=(2*(squareRoot(120)))/90==1.88.
Hence the current=(2*(squareRoot(120)))/90==1.88.
Ashish said:
8 years ago
For 2ac, both phases will be 90° apart. thus for 'i' instantaneous current, there will be -I current, means I current in opposite direction.
Thus resultant current will be zero.
Thus resultant current will be zero.
Vyas said:
6 years ago
Phase difference = (360°/number of phases). Therefore we have 180° phase difference in a 2 phase system. Since the load is resistive and balanced. The load currents will also have 180° phase difference.
Therefore the current in neutral which is phasor sum of load currents is also zero.
Therefore the current in neutral which is phasor sum of load currents is also zero.
Phantom said:
3 years ago
The right answer is option *C*
120/90 = 4/3.
4/3+1.3 = 2.63.
120/90 = 4/3.
4/3+1.3 = 2.63.
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