Current division for inductors

MrAl

Joined Jun 17, 2014
11,457
Hi,

Ok i'll have to go back to that problem and look at it again.
I must have done something different than you guys did.
Hi,

Ok, here is the analysis.
In the diagram see gray filled arrow, note that i get 60/80 same as the book and i used the relationship L2/(L1+L2).
See green filled arrow, i get all that too.
Did you do something different?
 

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MrAl

Joined Jun 17, 2014
11,457
No it works fine on this example, but for example check the attached example. It wont work for it.
Hi,

Ohhhh :)

So you were trying to disprove this for EVERY circuit. That's good to do too.

I'll check out that other circuit and problem again soon.
 

WBahn

Joined Mar 31, 2012
30,045
Hi,

Ok, here is the analysis.
In the diagram see gray filled arrow, note that i get 60/80 same as the book and i used the relationship L2/(L1+L2).
See green filled arrow, i get all that too.
Did you do something different?
You are cherry picking. You've claimed that those relationships apply in general and they don't. As I have stated over and over, they apply for circuits for which certain conditions are true. I even explicitly derived what those conditions are. You've cherry picked a problem for which the solution explicitly assumes such conditions.

I've asked several times for you to explain how your relations can be blindly used when they are not satisfied by the very first post in this thread and you have steadfastly refused to even address whether or not you agree with my assertion that they are not satisfied by the solutions to that problem.
 

MrAl

Joined Jun 17, 2014
11,457
You are cherry picking. You've claimed that those relationships apply in general and they don't. As I have stated over and over, they apply for circuits for which certain conditions are true. I even explicitly derived what those conditions are. You've cherry picked a problem for which the solution explicitly assumes such conditions.

I've asked several times for you to explain how your relations can be blindly used when they are not satisfied by the very first post in this thread and you have steadfastly refused to even address whether or not you agree with my assertion that they are not satisfied by the solutions to that problem.
Hello,

I think you should read post #63.
 

MrAl

Joined Jun 17, 2014
11,457
Hello,

I think you should read post #63.

Hello again,

Ok, not sure what happened there. A *quick* look at the FIRST problem tells me that the currents do not follow the inductor ratio relationships. I must have done that one different then quickly moved to the second problem. I got to this thread a little late.

But i wasnt "cherry picking" i just happened to concentrate more on the second problem than the first.

If you want to see real cherry picking then here ya go...
See what happens when we have L2=a*L1 and i1=a*i2. THAT is true cherry pickin' :) :)

In spite of all this, there is a relationship but it's not what we talked about so far. It's a bit more complicated and of course involves the initial currents in both inductors. But of course none of it holds if there is an external field coupling :)
 

WBahn

Joined Mar 31, 2012
30,045
In spite of all this, there is a relationship but it's not what we talked about so far. It's a bit more complicated and of course involves the initial currents in both inductors.
Yeah, that didn't start getting talked about all the way until Post #3.
 

MrAl

Joined Jun 17, 2014
11,457
Yeah, that didn't start getting talked about all the way until Post #3.
Hi again,

There's something i didnt like about these questions from the start either.
For one, there's nothing mentioned about using one of the ratios L2/L1, L1/L2, L1/(L1+L2), or L2/(L1+L2) as to when they could be used. It seemed like the second question would not have been complete had it not been for the given answers as well.

[BTW your idea of using Ebers Moll for comparison in the other thread worked out nicely.]
 
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