1. A Brief Introduction to Transformers
ECE 201 Circuit Theory 1

2. Transformer Construction
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3. Three-Phase Transformer
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4. Transformer Action -- DC
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5. Opposes battery voltage Opposes flux buildup
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6. Transformer Action -- AC
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7. ECE 201 Circuit Theory 1

8. Voltage ratio = Turns ratio
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9. “No-Load” Condition
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10. “No load” condition continued
Io = Ife + IM
Io = exciting current
Io provides the “magnetizing flux” and the “core loss”
Ife = core-loss current Ife = VT / Rfe
IM = magnetizing current IM = VT / jXM
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11. Component Fluxes – Loaded Transformer
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12. Φlp = leakage flux of primary Φls = leakage flux of secondary
ΦP = net flux in window of primary ΦS = net flux in window of secondary
Φlp = leakage flux of primary Φls = leakage flux of secondary
ΦM = mutual flux
ΦP = ΦM + Φlp
ΦS = ΦM – Φls
ECE 201 Circuit Theory 1