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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 2winding transformer this simpliﬁes to
N
V2 = N2 V1 and IL = −I2 = N1 I1
N
1 E1.1 Analysis of Circuits (20133867) 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 2winding transformer this simpliﬁes to
N
V2 = N2 V1 and IL = −I2 = N1 I1
N
1 Hence E1.1 Analysis of Circuits (20133867) 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 2winding 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 (20133867) 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.
 Fall '09

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