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.
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.
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.
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.
Sayed Tousif Pasha said:
1 decade ago
Whether the load is in series or parallel.
KeerthiRaj said:
1 decade ago
@Mr Parveen Kumar and Mr Sandeep Wasnik:
Although your ideas were wrong, but I think you people even don't know how to calculate phase to phase voltage, if you don't know please keep quiet, don't post wrong things.
Although your ideas were wrong, but I think you people even don't know how to calculate phase to phase voltage, if you don't know please keep quiet, don't post wrong things.
Manivel said:
1 decade ago
Consider two coils which are connected to the terminals A and B respectively. The other end of the coils terminated in neutral point N.
Since, Emf generated in each coil is 120 then current Ian (flows from A to N) = 1.33(120/90) and Ibn = 1.33(120/90).
Hence, the current in neutral wire is 1.33+1.33 = 2.66 A.
Since, Emf generated in each coil is 120 then current Ian (flows from A to N) = 1.33(120/90) and Ibn = 1.33(120/90).
Hence, the current in neutral wire is 1.33+1.33 = 2.66 A.
Somnath said:
1 decade ago
I think it's 2.66.
2 phase generator. So connect load of 2*90 ohm resistance in parallel.
Resultant resistance will be 45.
Then I = V/R.
= 120/45 = 2.66 A.
2 phase generator. So connect load of 2*90 ohm resistance in parallel.
Resultant resistance will be 45.
Then I = V/R.
= 120/45 = 2.66 A.
Kalai said:
10 years ago
Parallel connection, voltage same v = 120 v, R = 45 v, I = 120/45 = 2.66 A.
Vjagannadharao said:
10 years ago
Resistance will be 45.
And I = V/R.
V = 40, i = 120.
I = 120/45 = 2. 66 A a write method.
Current neutral wire is 1.33+1.33 = 2.66 A.
Then I = V/R = 2.66 A.
And I = V/R.
V = 40, i = 120.
I = 120/45 = 2. 66 A a write method.
Current neutral wire is 1.33+1.33 = 2.66 A.
Then I = V/R = 2.66 A.
Chandrima said:
10 years ago
Answer should be 1.88 amp.
V/i = 1.33 amp, current flowing through neutral 2*1.33 = 2.66, but RMS value of the current will be 2.66/sqrt2 = 1.88 amp.
V/i = 1.33 amp, current flowing through neutral 2*1.33 = 2.66, but RMS value of the current will be 2.66/sqrt2 = 1.88 amp.
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