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 4 of 7.
Hami said:
1 decade ago
I think 1.88 A is right answer. Because there is common neutral wire which means 1.33 A. After multiplying with 1.141, we get 1.88 A.
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.
Yousuf Hasan said:
1 decade ago
Circuit diagram is must, you don't know how the two resistor are connected? (series or parallel). For the line current you should know the equivalent resistance seen by the line.
Saheb said:
1 decade ago
Suppose, open delta connection neutral i = i/3^1/2.
Here, i = (120/90) + (120/90) = 2.66 A.
Neutral i = 2.66/3^1/2 = 1.54~1.77 A.
Here, i = (120/90) + (120/90) = 2.66 A.
Neutral i = 2.66/3^1/2 = 1.54~1.77 A.
RUPESH S BORADE said:
1 decade ago
If 2 resistance are in parallel then.
(90*90)/180 = 45.
I = V/R.
I = 120/45.
I = 2.66.
That's answer is C.
(90*90)/180 = 45.
I = V/R.
I = 120/45.
I = 2.66.
That's answer is C.
Sandeep wasnik said:
1 decade ago
There are the two phase and hence,
120*120 = 14400 volt.
90*90 = 8100 ohm.
Hence current (i) = v/r.
= 14400/8100 = 1.77 amp.
120*120 = 14400 volt.
90*90 = 8100 ohm.
Hence current (i) = v/r.
= 14400/8100 = 1.77 amp.
Parveen kumar said:
1 decade ago
There is 2 phase so voltage 120x120 = 14400.
2R = 90X90 = 8100.
I = V/R.
S0 = 14400/8100 = 1.77.
2R = 90X90 = 8100.
I = V/R.
S0 = 14400/8100 = 1.77.
Sachin said:
1 decade ago
Please give proper solution.
That justify answer is 1.77.
Because by calculations answer will come 1.88.
That justify answer is 1.77.
Because by calculations answer will come 1.88.
Khizar hayat said:
1 decade ago
It is double phase you have simply to do is,
v = 120 and R = 90.
(120.120) = 14400.
(90.90) = 1800.
We have i = v/R = 14400/1800 = 1.77.
D is the correct answer.
v = 120 and R = 90.
(120.120) = 14400.
(90.90) = 1800.
We have i = v/R = 14400/1800 = 1.77.
D is the correct answer.
Ram T Shelke said:
1 decade ago
In two phase system assuming phase diff equal to 90, the resultant voltage across a given resistor,
SQ ROOT(120*120+120*120) =170V.
Therefore current through neutral = current through given resistor = 170/90 = 1.888A.
SQ ROOT(120*120+120*120) =170V.
Therefore current through neutral = current through given resistor = 170/90 = 1.888A.
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