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phwcssin
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When I read the lecture notes about the ideal transformer, I have some problems about the proof of current relationship i1/i2=N2/N1=1/a.The proof is shown below.
Current Relationships of ideal transformer:
To get the current relationships use ampere's law
mmf= ∫H•ds= N1i1+N2i2’
H x length = N1i1+N2i2’
(B x length)/μ = N1i1+N2i2’
Assuming uniform flux density in the core
(φ x length)/( μ x area) = N1i1+N2i2’
If μ is infinite then 0 = N1i1+N2i2’ Hence i1/i2’= -N2/N1 or i1/i2=N2/N1=1/a
Questions:
1.when μ becomes infinity , is B still directly proportional to H here (is B=μH still worked )?
2.If μ becomes infinity then by B=μH as H has some values ,B becomes infinitely large?? μ=∞ ; B=μH=∞? But B will go saturated in reality...It contradicts that B=μH.
If B≠μH then mmf =Hl≠ φ x (l/μS) where l/μS is the reluctance .
Is the reluctance l/μS not suitable for the saturation region of B-H curve?3. I have read the book Power System Analysis by William D. Stevenson (P.45),the author said that B is not infinitely large,therefore integral value of must equal to zero.I don't understand his explanation.Can anyone explain in details to me? Thanks.
Another question: in reality,there is flux leakage around the core ,how can we use the ampere 's circuital law to calculate them?The leakage flux have many path...
Current Relationships of ideal transformer:
To get the current relationships use ampere's law
mmf= ∫H•ds= N1i1+N2i2’
H x length = N1i1+N2i2’
(B x length)/μ = N1i1+N2i2’
Assuming uniform flux density in the core
(φ x length)/( μ x area) = N1i1+N2i2’
If μ is infinite then 0 = N1i1+N2i2’ Hence i1/i2’= -N2/N1 or i1/i2=N2/N1=1/a
Questions:
1.when μ becomes infinity , is B still directly proportional to H here (is B=μH still worked )?
2.If μ becomes infinity then by B=μH as H has some values ,B becomes infinitely large?? μ=∞ ; B=μH=∞? But B will go saturated in reality...It contradicts that B=μH.
If B≠μH then mmf =Hl≠ φ x (l/μS) where l/μS is the reluctance .
Is the reluctance l/μS not suitable for the saturation region of B-H curve?3. I have read the book Power System Analysis by William D. Stevenson (P.45),the author said that B is not infinitely large,therefore integral value of must equal to zero.I don't understand his explanation.Can anyone explain in details to me? Thanks.
Another question: in reality,there is flux leakage around the core ,how can we use the ampere 's circuital law to calculate them?The leakage flux have many path...
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