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 5 of 7.
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.
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.
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)
Awesome said:
9 years ago
@Amjad.
How have you done this. Is there any formula like that?
How have you done this. Is there any formula like that?
Ayush Kumar said:
9 years ago
It is simple question since, two phase generator is connected to two load resistor therefore resistance = 90 * 90 = 8100 & total voltage = 120 * 120 = 14400.
Therefore required current through common neutral line is = 14400/8100 = 1.77A.
Therefore required current through common neutral line is = 14400/8100 = 1.77A.
(2)
Rachappa said:
9 years ago
Is there any formula to find this answer?
Suryabai said:
9 years ago
Which is the correct answer? Please tell the correct option.
Aditya bakshi said:
9 years ago
I think the answer is c, if the answer is D please give me the correct explanation.
Ali said:
9 years ago
According to me, the answer is 2.66.
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.
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