Question

b) the r.m.s.value of the supply current c) the r.m.s.value of the current, and d) the resultant power factor of the circuit 17 ELE2601/101/3/2018 4.2 A balanced three-phase load is connected to a three- phase, 380-V supply. The load takes 7,5 kW at a power factor of 0,8 lagging. Calculate the resistance and reactance of each phase if the load is star-connected. 4.3 A three-phase cable supplies power to a balanced three- phase load. Each conductor carries a current of 120 A per phase and each conductor has a resistance of 0.4 ? per phase. The power factor of the load is improved so that the line current is reduced to 90 A. Calculate the percentage change in power loss in the cable. 44 Refer to figure 4. The phasor diagram and connection diagram is applicable on a three-phase system. Calculate the reading on the wattmeter 15 A VAR 24 A VL-440Vv 30 A VCA c Figure 4 121] QUESTION 5 5.1 What is a summetrical th ree-phase supply? 5.2 Define the term power factor 5.3 Explain why a load will have a lagging power factor 5.4 Mention five detrimental effects of harmonics in electrical TOTAL: [109] 18

Answer 1

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