Unsolved questions from Unit 2, Inductance calculations.

1. Chapter 3 Questions
Q1. A wire 4mm in diameter is suspended at a constant height 10m above sea level which constitutes
the return conductor. Calculate the inductance of the system per km. [1.89mH]
Q2. In the fig. (1 phase, double circuit), given below, find inductance per km length of the line. Dia of
each conductor is 2 cm. [1.17mH]
Q3. If dia is 8mm, find the inductance per km of the line. [1.54mH]
Q4. A 3 phase 3-wire system consisting of 12.50mm dia conductors spaced 3m apart in a horizontal
plane supplies a balanced load. Calculate the inductance per KM of each conductor (line to neutral).
What will be the inductance of each phase if conductors were regularly transposed? [La =1.35 –
j0.12 mH/Km; Lb=1.28mH; Lc = 1.35 + j0.12 mH; when transposed La = Lb = Lc = 1.33mH/km]
Q5. Find the effective inductance per km of each phase if h = 3m, d = 1.5m, r=12.50cm. Assume
transposition. [0.51mH/Km]

2. Q6. The six conductors of a double circuit 3 phase line are arranged as shown in the fig. the dia of each
conductor is 2.532cm. Assume that the line is transposed. Find inductance/phase/km. [0.606mH]
Q7.Dia is 5.0cm, find inductance per phase. Assume transposition. [0.92mH/km]