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A balanced star-connected and purely resistive load is connected at the secondary of a star-delta transformer as shown in the figure given below. The line-to-line voltage rating of the transformer is 110 V/220V. Neglecting non-idealities of the transformer, impedance ‘Z’ of the equivalent star-connected load, referred to the primary side of the transformer, is
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- (3 + j0)Ω
- (0.866 – j0.5)Ω
- (0.866 + j0.5)Ω
- (1 + j0)Ω
Correct Option: D
| v1 = | v2 = 220 | |
| √3 |
| But i2 = | = | amp | ||
| √3 | 8√3 |
Now i1v1 = i'2 v2
| ∴ i1 . | = i²1.220 | |
| √3 |
| ⇒ | = 2√3 | |
| i²1 |
| i1 2√3 . | = | = 55 amp | ||
| 8√3 | 8 |
∴ 110 = 2z * i1
| z = | = 1 | |
| 2 × 55 |
∴ z = 1+ j0.
