Chapter 7, Problem 11P

Two loads connected in parallel are respectively 2 kW at a pf of 0.75 leading and 4 kW at a pf of 0.95 lagging. Calculate the pf of the combined two loads. Find the complex power supplied by the source. Hints: • • Since the two loads are parallel, the complex power, S, supplied by the source is S = S₁+ S₂ Calculate the complex powers, S₁ and S2, of each load (use power triangles) and add them to find the total S. Calculate 0 and obtain pf.

Starting from Maxwell’s equations derive the Kirchohf’s circuit laws for voltage and current. Clearly mention what approximation is used for this derivation.

In the control system shown in Figure Q4(a), G₁(s) = and G₂(s) == If the system has the specifications for the natural frequency and dampingratio of -5 rad/sec and {=0.7, respectively, determine K and H,(s) when H₂(s) = 1.