2023-03-23 11:26:34 +00:00
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---
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author: Akbar Rahman
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date: \today
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title: MMME2051 // Transformers
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tags: [ transformers, alternating_current, ac ]
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uuid: 486f441f-14ec-41e5-94f9-06f25c534086
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lecture_slides: [ ./lecture_slides/MMME2051EMD_Lecture8.pdf ]
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exercise_sheets: [ ./exercise_sheets/Exercise Sheet 11 - Transformers.pdf ]
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---
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Transformers are used to convert between AC voltages.
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Transmission is always done at very high voltage to reduce copper losses (heat loss, $E = i^2R$).
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A current carrying coil induces a magnet inside the core.
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Another coil is wrapped around the core.
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This coil has a current induced in it by induced magnetic field.
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$$\frac{i_s}{i_p} = \frac{v_p}{v_s} = \frac{n_p}{n_s} = \text{turns ratio}$$
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**Note that the current fraction is s over p, not p over s like the others.**
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2023-03-23 11:54:24 +00:00
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Transformers have very high efficiency so will not be considered for this module and
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has been left out of the equation above.
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2023-03-23 11:26:34 +00:00
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Derivation in lecture slides (pp. 12-15).
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Transformers are usually described as having a ratio $p:s$, where $p$ is the number of primary coils
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and $s$ the number of secondary coils.
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## Referred Impedance
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$$\frac{Z_P}{Z_S} = \left(\frac{n_p}{n_s}\right)^2$$
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Derivation in in lecture slides (pp. 19-21).
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