A 1 - ϕ circuit with a supply voltage 'V' consists of resistance
| A 1 - ϕ circuit with a supply voltage 'V' consists of resistance 'R’ and reactance 'X' in series. The locus of current is a circle with a radius of when ‘R’ is varied.
A. V/X
B. V/2X
C. V/πX
D. V/2πX
Please scroll down to see the correct answer and solution guide.
Right Answer is: B
SOLUTION
Locus diagram:
The locus diagram is useful for the analysis and designing of the circuit.
Ex: Filters
Current locus diagram:
The single-phase circuit with series R-L is shown below.
R= Resistance
X= Inductive reactance.
the effect of variation in R is shown below
|
R |
Z = R + j X |
I = (V/Z) |
Θ = tan-1 (X/R) |
|
0 |
X |
V/X |
900 |
|
Increases |
increases |
Decreases |
decreases |
|
∞ |
∞ |
0 |
00 |
The current locus diagram for the above circuit is shown below.
From the diagram,
Diameter = (V/X)
Radius = (V/2X)
Centre = (0, (V/2X))
Important points:
- When the power factor angle is variable, the shape of the current locus is a semi-circle.
- When the power factor angle is constant, the shape of the current locus is a Straight line.
