Series parallel magnetic circuit

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Andymayers8
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Homework Statement


The attached figure shows a magnetic series parallel circuit with an air gap, what I'm not sure of is how to add the individual reluctances of the core and air gap to get the total reluctance required to calculate the current.

Homework Equations





The Attempt at a Solution


My attempt was that the first "complete" square of core is added in series and then the other 3 sides of the square and the air gap are all added in series then these two totals are added together in parallel? Is this correct?

Any help would be appreciated
 
Attachments
  • Figure Q1: series-parallel magnetic circuit with an 800-turn coil N and current I, a rectangular core with dimensions 2cm, 7cm, 3cm, 6cm, 2cm, 4.5cm, 0.5cm and 5cm, and a 0.5cm air gap on the right limb.
    image.jpg
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Last edited:
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This is hard to agree on without drawing it out. However no one can draw it out.. maybe the best thing to do would be to draw out what you mean.

My advice would be to remember that you are using the average flux path.. so work 'in the middle' of the core and don't go 'completely to the ends'.

You should have three branches in parallel. One of the three branches should include a core reluctance and an air gap reluctance while one of the three pieces includes an MMF
 
Thanks for the reply, and I have calculated as you have said to the 'middle of the core'

Do you mean something like the attached picture?
 
Attachments
  • Hand-drawn magnetic circuit diagram, rotated on lined paper, with an MMF source and three reluctances labelled Rc, Rc and RAG. Rc and RAG are in series on the top branch, and the middle Rc sits in parallel with that branch, with the lower Rc in series with the MMF.
    image.jpg
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Yes now the reluctances are calculated using the average flux path. So use total cross sectional area but average length.

You are given enough information (the flux density in the gap) to compute a valuable piece of information that along with the individual reluctances, will get you to the answer