Question

The symmetrical load below is connected to a three-phase network. A line current of 25A has been measured. The load resistors have a value of 18 Ω.
What is the line voltage of the three-phase network?

Answer 1

Answer:

The line voltage of the three phase network is 346.41 V

Explanation:

Star Connected Load

Resistance, R₁ = R₂ = R₃ = 18 Ω

For a star connected load, the line current = the phase current, that is we have

$I_L = 25 \, A = I_{Ph}$

Whereby the the voltage across each resistance = $V_R$ is given by the relation;

$V_R$ = $I_{Ph}$ × R

Hence;

$V_{Ph}$ = $V_R$ = $I_{Ph}$ × R  = 25 × 8 = 200 V

Therefore we have;

The line voltage, $V_{L}$ = √3 × $V_{Ph}$ = √3 × 200 = 346.41 V.

Hence, the line voltage of the three phase network = 346.41 V.