Calculate the power of the coils in this RLC circuit

[Edy56]

Homework Statement

I need to solve for power of the coils

Relevant Equations

none

So my attempt was
I1*jXl1+I2*jXm=I2*(jXl2-jXc2) + I1*jXm
because they are parallel so they should have the same voltage.
I got
I1=-3*I2.
I know that J=6-j4 and that J=I1+I2 so I just plugged in what I got and I ended up getting the result for I2 and I1.
But they are not correct.
Why?
I am given R and I never use it so I assume it has something do do with it.

 

[erobz]

Please, take a moment to learn LaTeX Guide. And use it to re-write your equations.

 

[Baluncore]

How can there be any power dissipated in the coils?
They have no real series resistance, so the product of v, and quadrature i, is imaginary = VAR.

 

[Edy56]

How can there be any power dissipated in the coils?
They have no real series resistance, so the product of v, and quadrature i, is imaginary = VAR.

In the circuit determine the complex powers of the coupled coils.

 

[Babadag]

If Xm=0 then I1*jXL1=I2*j(XL2-XC).

Where is Xm located? It could be in Слика 1?

 

[Edy56]

If Xm=0 then I1*jXL1=I2*j(XL2-XC).

Where is Xm located? It could be in Слика 1?

no Xm= X12 which is mutual coupling.
to my knowledge, since this is coupled coils
Ul1=jXl1*I1 +\- jXm*I2
Ul2=jXl2*I1 +\- jXm*I1

 

[Babadag]

Something like this?

 

[Edy56]

Something like this?

I am not too sure because we havent been taught that we can do that, but going from the videos I have seen, it would do the same thing

 

[DaveE]

Here's an old post about modeling coupled inductors as circuit elements:
https://www.physicsforums.com/threa...ng-high-low-power.1001193/page-2#post-6478419

Certainly not the only approach, but it's the one I used a lot.

 

[DaveE]

Are you sure they are coupled inductors? It seems odd that they wouldn't tell you the turns ratios or coupling coefficients.

 

[Babadag]

This is the diagram of a transformer. Then a more simplified diagram can be used:

 

[Babadag]

Then, if it is the diagram of a transformer, the left part is the primary and the right part is the secondary.
The diagram is viewed from primary side. That means, the secondary actually circuit elements [XL2 and XC] are multiplied by the square of number of turns of primary divided by number of turns of secondary.
The current through the primary and secondary windings are inversely proportional with the number of turns in windings.
N1*I1+N2*I2=N1*Io
Io is the primary current in absence of secondary current.
If N1=N2 [ since the reference to primary is already done] I1+I2=Io
Neglecting Io [usually it is about 1-3% I1] I1=-I2.
So, both current are I1=J and I2=-J
The reactances shown above: XL1 and XL2 , are connected with the leakage of magnetic flux from each winding [primary and secondary]
As it is said above, the power from coils-only in XL1 and XL2- it is only a reactive power.
Active power is only from R [ the R on the secondary side is also neglected]

 

[Edy56]

this is getting a bit too complex for my level lol