Assignment:
A factory’s electrical load can be represented as three parallel admittances (see attachment). The values of the admittances are given in the table in polar form.
a) Determine
i. The current taken from the supply
ii. The overall power factor of the load
iii. The value of the capacitor required in parallel to the load to reduce the supply current by 20% and the new power factor with the capacitor in circuit
b) The power factor for the factory load can be improved to unity by using a sufficiently large parallel capacitor.
i. Calculate the value of this capacitor
ii. Calculate the resonant frequency of the circuit when this capacitor is in circuit (using the condition that at resonance BC = BL, like XC = XL in a series circuit). Please comment on this answer.
iii. State, with reasons, if the ‘unity power factor’ condition gives the minimum value of supply current.
