  Basic Electronic

Transformer Operation

TRANSFORMER OPERATION

A transformer is an dectromagnetic device having two or more mutually coupled windings (share a common magnetic circuit). Figure 4 shows a two-winding, ideal transformer; the transformer is ideal in the sense that its core is lossless and is infinitely permeable, it has no leakage fluxes, and the windings have no losses. In Figure 4, the basic components are the core, the primary winding, N1, and the secondary winding, N2. If Φ is ,the mutual (or core) flux threading each turn of N1 and N2, then according to Faraday´s law of electromagnetic induction, emfs e1 and e2 are induced in N1 and N2, given by (Formula 9) The direction of e is such as to produce a current that gives rise to a flux which opposes the flux change
(Lenz´s law).  From (9), e1/e2 = N1/ N2, or, in terms of rms values,  (Formula 10)

where a is the turns ratio. The transformer being ideal, e1 = v1 and e2 = V2  in Fig. 4; hence the flux and voltage are related by  (Formula 11) If the flux varies sinusoidally, Φ = Φm sin ωt, then the corresponding induced voltage, e, in an N-turn winding is given by e = ωN Φmcosω(13.12)
and the rms value of this induced voltage is  (Formula.13) which is known as the em! equation. In (13),   j = ω/2л is the flux frequency in Hz. Keywords : Transformer, Operation, Energy, Magnetic, Induction, Transformer, Transformation, Electrical, Electronic
Writer : delon  |
16 Mar 2006 Thr
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