A balanced Δ-connected load has an impedance of 16 + j12 Ω per phase. It is supplied from a balanced three-phase source with a line-to-line voltage of 600 V. Find the magnitude of the phase current Iph flowing through each impedance.
Three-phase power worksheet with answers
A balanced Y-connected load has an impedance of 12 + j16 Ω per phase. It is supplied from a balanced three-phase source with a line-to-line voltage of 400 V. Find the magnitude of the line current IL.
A three-phase induction motor delivers 15 kW of mechanical output power at full load. At this load its efficiency is 90% and its power factor is 0.84 lagging. The supply has a line-to-line voltage of 415 V. Find the line current IL.
A balanced Δ-connected load with an impedance of 7 + j24 Ω per phase is connected to a balanced three-phase supply with a line-to-line voltage of 208 V. Find the total real power P absorbed by the load in kW.
A balanced three-phase load takes 50 kW at a power factor of 0.75 lagging from a 480 V (line-to-line), 60 Hz supply. A three-phase capacitor bank in parallel with the load must raise the overall power factor to 0.98 lagging. The real power stays the same. The capacitors are connected in Y. Find the capacitance Cph of each capacitor in µF.
A balanced three-phase load takes 60 kW at a power factor of 0.78 lagging from a 400 V (line-to-line), 60 Hz supply. A three-phase capacitor bank in parallel with the load must raise the overall power factor to 0.92 lagging. The real power stays the same. The capacitors are connected in Y. Find the capacitance Cph of each capacitor in µF.
Answer key
- 1. Iph = 30 A
- 2. IL = 11.55 A
- 3. IL = 27.6 A
- 4. P = 1.454 kW
- 5. Cph = 390.8 µF
- 6. Cph = 374.3 µF
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