Hello everyone,

Actually I not understand the Mutual Inductance analysis circuit, but I do one problem ....

Please can you check my solution true or wrong,

thanks,

 

I don't see how the mutual inductance can be 1H when with perfect coupling it can't be greater than 0.3536H.

\(M=k \sqrt{L_1L_2}\)

 

I don't see how the mutual inductance can be 1H when with perfect coupling it can't be greater than 0.3536H.

\(M=k \sqrt{L_1L_2}\)

can you see this youtube

but I not understand in this video how do mutual inductance analysis

how I know the mutual inductance is positive or negative ?

but I do my problem form this key:

 

I fail to see the the point of trying to solve a problem based on a false premise.

 

how I know the mutual inductance is po

I fail to see the the point of trying to solve a problem based on a false premise.

ok sir, I will do another problem

 

I do new problem , please check loops 1&2 :

thanks,

 

You do have a problem with the dot convention.

My approach is simply to say:
Current flowing into a dot on a winding produces a positive mutually induced emf at the dot on mutually coupled windings.

So for your first mesh equation:

\( -800+200I_1+j480I_1+j360 (I_2-I_1)+j720 (I_1-I_2)-j360I_1=0 \)

 

You do have a problem with the dot convention.

My approach is simply to say:
Current flowing into a dot on a winding produces a positive mutually induced emf at the dot on mutually coupled windings.

So for your first mesh equation:

\( -800+200I_1+j480I_1+j360 (I_2-I_1)+j720 (I_1-I_2)-j360I_1=0 \)

but I think in rule of thumb on dot convention ( flow into*flow out =>negative)

what is meaning emf?

thanks,

 

In reality you can adopt whatever convention you like as long as you are consistent with the application of the "rules".
The meaning of emf - electro-motive force.

 

sir, first of all, what is the meaning of the "dot"? (Mutual Inductance )true?

and how can be calculated? thanks for your nice support

 

The dot indicates there is magnetic flux coupling between one or more inductors as represented in a schematic diagram.
As shown in your schematics the mutual inductance between the various inductors is indicated by the arrow(s) with an annotated value in units of inductance. Sometimes only the coefficient of coupling is shown and one then apples the formula for mutual inductance to determine the actual value.
The location of the dot indicates the mutually induced voltage (emf) polarity in an inductor for a given condition (voltage or current) in a another mutually coupled inductance.

 

My solution attached.

 

The dot indicates there is magnetic flux coupling between one or more inductors as represented in a schematic diagram.

Interesting. I tended to believe the dots represented phasing, so you can tell whether or not the mutual inductance is aiding or opposing.

 

hi Joe,
I agree, its the winding phase indicator.
I also consider it as the start of a winding.
E

http://www.allaboutcircuits.com/vol_2/chpt_9/4.html

 

Thank you sir ,

 

The dot indicates there is magnetic flux coupling between one or more inductors as represented in a schematic diagram.

Shouldn't that be two or more inductors?

I remember a post in a newsgroup from some years ago concerning the situation where 3 inductors were coupled. A Spice simulation complained that the various mutual inductances were not physically realizable. Somebody posted a reference from an IEEE journal article where it was explained that if the matrix of self and mutual inductances were formed, it had to be positive definite to be realizable.

 

I am do this problem 3 time same answer :
where is wrong?

thanks

 

The problem is with mesh 1 equation. Specifically, the term -j2*I1 should be positive sign rather than negative.

 

The problem is with mesh 1 equation. Specifically, the term -j2*I1 should be positive sign rather than negative.

obs

thanks sir

 

I am do this problem in ideal transformer :
where is wrong?

thanks