Q2 (a) Define the meaning of the balanced supply in the three
phase system.
(b) Distinguish four (4) possible configuration of the
balanced three phase system.
(c) The line voltages applied across the life terminals of a
balanced four-wire system,
star connected load are 400 V. The load impedance consists of
a 4 Ω resistor that is
in series with an inductor while the power factor of the
system is equal to 0.75,
assume the phase sequence is RYB.
(i) Sketch the circuit diagram of the system.
(1 mark)
(ii) Calculate the phase voltages of each loads.
(iii) Calculate the phase currents that flow into each
loads.
(iv) Draw the phasor diagram of the load currents.
(v) Draw the phasor diagram of the load voltages.
(d) A balanced three-phase delta connected source supplies
line currents of 15A to a
balance three-phase star connected load, consider the line
current of Ia as a reference
and the phase sequence is RYB. The load in each phase is
composed of two (2)
units of 8 + j6 Ω impedances that are connected in
parallel.
(i) Sketch the circuit diagram of the system.
(1 mark)
(ii) Calculate the phase currents of the source.
(iii) Deduce the phase currents of the load.
(iv) Calculate the phase voltage of the source.
(v) Draw the phasor diagram for the phase currents, line
currents and phase
voltages of the voltage sources.