In a three-phase load, ______ different impedances are connected
A. six
B. zero
C. three
D. one
Please scroll down to see the correct answer and solution guide.
Right Answer is: C
SOLUTION
In a three-phase load, three different impedances are connected together in a star or delta fashion.
The delta in a three-phase system is formed by connecting one end of the winding to the starting end of other winding and the connections are continued to form a closed loop.
The star in the three-phase system is formed by connecting one end of all three impedances are connected together.
Important Points:
In a star-connected three-phase system,
VL = √3 × Vph
And IL = Iph
\({I_{ph}} = \frac{{{V_L}}}{{\surd 3Z}}\)
In a delta connected three-phase system,
VL = Vph
IL = √3 × Iph
\({I_{ph}} = \;\frac{{{V_L}}}{Z}\)
Where,
VL is line voltage
Vph is phase voltage
IL is line current
Iph is the phase current