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.
Amjad moawia said:
9 years ago
There is the two phase.
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.
(2)
Vijay yadav said:
10 years ago
I am correcting answer of @Mr Rasood.
I = 120/90*1.414 = 1.88 A since the currents are 90 degrees out of phase.
Could also be written as I = 1.33 + j 1.33 (rectangular form) = 1.88 A at 45 degrees (polar form).
= 1.88*cos 45.
= 1.88*1/square root (2).
= 1.88/1.41 = 1.33.
I = 120/90*1.414 = 1.88 A since the currents are 90 degrees out of phase.
Could also be written as I = 1.33 + j 1.33 (rectangular form) = 1.88 A at 45 degrees (polar form).
= 1.88*cos 45.
= 1.88*1/square root (2).
= 1.88/1.41 = 1.33.
NASR said:
10 years ago
Right answer is D because:
1 = 120/90a with angle 0+120/90 with angle 120.
= 1.33+j0-0.665+j1.152.
1 = 120/90a with angle 0+120/90 with angle 120.
= 1.33+j0-0.665+j1.152.
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.
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.
Kalai said:
10 years ago
Parallel connection, voltage same v = 120 v, R = 45 v, I = 120/45 = 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.
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.
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.
Sayed Tousif Pasha said:
1 decade ago
Whether the load is in series or parallel.
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