(a) If a 50 Hz voltage source is connected across points AG in Fig 01, calculate,
(i) The reactance between points AB In magnitude and phase.
(ii) The impedance between points BC in magnitude and phase.
(iii) The equivalent circuit impedance in magnitude and phase.
(iv) The current flowing iiiinductor L1 in magnitude and phase using the principle of current division.
(v) The supply voltage in magnitude and phase.
(vi) The power dissipated by resistor R1.
(b) An unbalanced 4-wire star connected load is supplied with 400V. The loads are; ZR (3 + j5) 0, Zy = (2 j4) 0 and ZB = (4 -4- j3) CI.
Determine,
(i)The line currents and the current in the neutral line in magnitude and phase:
b) The magnetic circuit lengths of a laminated iron frame, which comprises of a centre limb with two outer limbs, are given below. The cross-sectional area of each of the outer limbs is 0.0004m2 and each with a mean path length of 0.2m. The cross-sectional area of the centre limb 0.0008m2 and has a mean path length of 0.08m. A 308-
turn coil is wound on the centre limb.
What value of excitation current will be required to establish a flux of 0.42mWb in each of the outer limbs?
Data for the relevant part of the magnetization curve for the iron is as follows:
Flux Density (Testa) 0.9 1.1 1.2 1.25
Magnetizing Force (Alm) 350 650 975 1200
