Lecture Notes14_AcPower

# 1 2 3 assume n1 i1 n2 i2 n3 i3 0 e11 analysis of

This preview shows page 1. Sign up to view the full content.

This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: on • Ideal Transformer • Transformer Applications • Summary V = 230. Motor modelled as 5||7j Ω. V I = V + ZL = 46 − j 32.9 A = 56.5∠ − 36◦ R S = V I ∗ = 10.6 + j 7.6 kVA = 13∠36◦ kVA cos φ = |P | = cos 36◦ = 0.81 S Add parallel capacitor of 300 µF: ZC = 1 jωC = −10.6j Ω ⇒ IC = 21.7j A I = 46 − j 11.2 A = 47∠ − 14◦ A ∗ SC = V IC = −j 5 kVA S = V I ∗ = 10.6 + j 2.6 kVA = 10.9∠14◦ kVA cos φ = |P | = cos 14◦ = 0.97 S Average power to motor, P , is 10.6 kW in both cases. I , reduced from 56.5 47 A (−16%) ⇒ lower losses. Effect of C : VARs = 7.6 2.6 kVAR E1.1 Analysis of Circuits (2013-3867) AC Power: 14 – 8 / 11 Power Factor Correction 14: Power in AC Circuits • Average Power • Cosine Wave RMS • Power Factor • Complex Power • Power in R, L, C • Tellegen’s Theorem • Power Factor Correction • Ideal Transformer • Transformer Applications • Summary V = 230. Motor modelled as 5||7j Ω. V I = V + ZL = 46 − j 32.9 A = 56.5∠ − 36◦ R S = V I ∗ = 10.6 + j 7.6 kVA = 13∠36◦ kVA cos φ = |P | = cos 36◦ = 0.81 S Add parallel capacitor of 300 µF: ZC = 1 jωC = −10.6j Ω ⇒ IC = 21.7j A I = 46 − j 11.2 A = 47∠ − 14◦ A ∗ SC = V IC = −j 5 kVA S = V I ∗ = 10.6 + j 2.6 kVA = 10.9∠14◦ kVA cos φ = |P | = cos 14◦ = 0.97 S Average power to motor, P , is 10.6 kW in both cases. I , reduced from 56.5 47 A (−16%) ⇒ lower losses. Effect of C : VARs = 7.6 2.6 kVAR , power factor = 0.81 E1.1 Analysis of Circuits (2013-3867) 0.97. AC Power: 14 – 8 / 11 Ideal Transformer 14: Power in AC Circuits • Average Power • Cosine Wave RMS • Power Factor • Complex Power • Power in R, L, C • Tellegen’s Theorem • Power Factor Correction • Ideal Transformer • Transformer Applications • Summary A transformer has ≥ 2 windings on the same magnetic core. E1.1 Analysis of Circuits (2013-3867) AC Power: 14 – 9 / 11 Ideal Transformer 14: Power in AC Circuits • Average Powe...
View Full Document

Ask a homework question - tutors are online