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A three phase 50Hz line consists of three conductors each of diameter 21 mm. The spacing between conductors is as shown. The inductance per phase per km of the line will be
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- 12.2 × 10–4 H/km
- 8.2 × 10–4 H/km
- 5.6 × 10–3 H/km
- none of these
Correct Option: A
| r' = 0.7788 r = 0.7788 × | × 10-3 m. | |
| 2 |
Deq = (3 × 5 × 3.6)1/3 = 3.78 m
| L = 2 × 10-7 In |  |  | ||
| r' |
| 2 × 10-7 |  | In |  | |
| (0.7788 × 10.5 × 10-3) |
= 2 × 10-7 ln (46.22)
= 2 × 10-7 × (6.136)
= 12.2 × 10-7 H/m
= 12.2 × 10-4 H /km
