Lecture Notes14_AcPower

# An n 1 transformer reduces the microphone voltage by

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Unformatted text preview: all windings, N1 = N2 = N3 . 1 2 3 Assume µ → ∞ ⇒ N1 I1 + N2 I2 + N3 I3 = 0 These two equations allow you to solve circuits and also imply that Si = 0. Special Case: For a 2-winding transformer this simpliﬁes to N V2 = N2 V1 and IL = −I2 = N1 I1 N 1 E1.1 Analysis of Circuits (2013-3867) 2 AC Power: 14 – 9 / 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. V Faraday’s law: Nr = dΦ . dt r N1 : N2 + N3 shows the turns ratio between the windings. The • indicates the voltage polarity of each winding. Nr Ir = Ampère’s law: lΦ µA ; V V V Since Φ is the same for all windings, N1 = N2 = N3 . 1 2 3 Assume µ → ∞ ⇒ N1 I1 + N2 I2 + N3 I3 = 0 These two equations allow you to solve circuits and also imply that Si = 0. Special Case: For a 2-winding transformer this simpliﬁes to N V2 = N2 V1 and IL = −I2 = N1 I1 N 1 Hence E1.1 Analysis of Circuits (2013-3867) V1 I1 2 = N1 N2 2 V2 IL = N1 N2 2 Z AC Power: 14 – 9 / 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. V Faraday’s law: Nr = dΦ . dt r N1 : N2 + N3 shows the turns ratio between the windings. The • indicates the voltage polarity of each winding. Nr Ir = Ampère’s law: lΦ µA ; V V V Since Φ is the same for all windings, N1 = N2 = N3 . 1 2 3 Assume µ → ∞ ⇒ N1 I1 + N2 I2 + N3 I3 = 0 These two equations allow you to solve circuits and also imply that Si = 0. Special Case: For a 2-winding transformer this simpliﬁes to N V2 = N2 V1 and IL = −I2 = N1 I1 N 1 Hence V1 I1 2 = N1 N2 2 V2 IL = N1 N2 2 Z Equivalent to a reﬂected impedance of E1.1 Analysis of Circuits (2013-3867) N1 N2 2 Z AC Power: 1...
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## This document was uploaded on 02/20/2014 for the course EE 101 at WVU.

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