How to Calculate RMS Current and Voltage in an AC Magnetic Circuit?

[spoonjabba]

the question is;


if there only a current in coil a, and it is AC, calculate the rms current required in coil a to maintain an alternating flux in core section a with a peak value of 1.2T calculate the rm voltages at the two coil terminals if coil resistances are neglected

(attached in the previous question which is continued on by this)

So I derived the magnetic equivalent of this circuit which is basically mmf connected to reluctance (R) equivalent. What do I do from here?

at the moment I am here;

F = R * Flux

With that

F= NI, N = 200, R = Req which i have found already and flux = B*A

200 I = Req * B*A

do i substitute in 1.2T for b and solve for I? then multiple by √2 or am i going in the complete wrong direction?

help will be greatly appreciated.

 

[rude man]

Did they give you the permeability?

 

[spoonjabba]

relative permeability is 10,000,
multiply that by uo

 

[rude man]

the question is;


if there only a current in coil a, and it is AC, calculate the rms current required in coil a to maintain an alternating flux in core section a with a peak value of 1.2T calculate the rm voltages at the two coil terminals if coil resistances are neglected

(attached in the previous question which is continued on by this)

So I derived the magnetic equivalent of this circuit which is basically mmf connected to reluctance (R) equivalent. What do I do from here?

at the moment I am here;

F = R * Flux

With that

F= NI, N = 200, R = Req which i have found already and flux = B*A

200 I = Req * B*A

do i substitute in 1.2T for b and solve for I? then multiple by √2 or am i going in the complete wrong direction?

help will be greatly appreciated.

the question is;


F= NI, N = 200, R = Req which i have found already and flux = B*A

200 I = Req * B*A

do i substitute in 1.2T for b and solve for I? then multiple by √2 or am i going in the complete wrong direction?

help will be greatly appreciated.

Well, you got NI = flux*reluctance right, so what's preventing you from solving for I? And yes, you need to divide by √2 to get rms current. The formula NI = R*flux is for instantaneous values of I and flux.

To get the two winding voltages you go to Mr. Faraday.


(Realize that there are two reluctance paths, right?)

 

[rezeew]

I would first suggest double-checking your calculations and equations to ensure they are correct. It is important to have accurate values and equations before moving forward with the problem.

Assuming your equations and values are correct, you are on the right track. To calculate the RMS current required in coil a, you can substitute the given peak flux value of 1.2T for B in your equation. Then, solve for I. This will give you the RMS current required to maintain an alternating flux of 1.2T in core section a.

Next, to calculate the RMS voltage at the two coil terminals, you can use Ohm's Law (V = IR) to find the voltage drop across each coil. Since the resistance of the coils is neglected, the voltage drop will be equal to the RMS voltage at the terminals.

I hope this helps guide you in the right direction. Remember to always double-check your calculations and equations to ensure accuracy. Good luck with your problem!