# Series parallel magnetic circuit

1. Feb 17, 2014

### Andymayers8

1. The problem statement, all variables and given/known data
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.

2. Relevant equations

3. 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

#### Attached Files:

• ###### image.jpg
File size:
39.4 KB
Views:
719
Last edited: Feb 17, 2014
2. Feb 17, 2014

### FOIWATER

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

3. Feb 17, 2014

### Andymayers8

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?

#### Attached Files:

• ###### image.jpg
File size:
31.4 KB
Views:
284
4. Feb 17, 2014

### FOIWATER

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

5. Feb 17, 2014

### Andymayers8

Ok thanks a lot for the help!

6. Feb 17, 2014

### FOIWATER

You are most welcome.