Found the problem: I used the divergence theorem incorrectly.
Volume integral of field divergence is equal to the closed surface integral of the field itself, not its divergence.
F = \int_{V} \mathbf{f} \mathrm{d} V = \int_{V} (\nabla\cdot\sigma)\mathrm{d} V = \oint_{S}...
Thank you. I forgot to mention that the iron has ideal (linear) magnetic properties such that:
B_{iron} = \mu_{r} \cdot \mu_{0} \cdot H_{iron}
Also, the permanent magnet has a linear loading curve:
B_{mag} = B_{R} \cdot (1-H_{mag}/H_{c})
Motor control engineer here (so my answer is not really physics-based):
Torque - EM torque developed by an electric machine
External torque - torque imposed by load (positive - generators such as gas/wind, negative - fans, compressors, etc.)
(this is not a hw)
Assume you have a magnet of dimensions x_m, h_m, remanent flux density Br, and coercive field density Hc. The magnet is placed in a magnetic "C" structure (perfect iron) such that it is connected on one side but there is an airgap on the other side.
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Not all non-charity related funds are spent on missionaries. I can write about the local RC church here on our block-- masses are free though most people donate a few dollars here and there. To my understanding, most money is redistributed back into society through the priest- I believe some...
Claude,
I think we both agree on this.
To my knowledge, the single switch forward converters have a mechanism to reset the magnetizing current each cycle. Also, why would you store energy in a transformer core when the energy is not needed?
I do not deny the fact that one could use a...
cabraham,
While I am not refusing your reasoning and I do not want to bicker over pedantry, I could not help myself to write at least the following paragraph. In case I am wrong, I will be happy to learn something new or correct my mistakes.
Xfrm action can happen with a flux DC offset just...
A couple of things to do in case you would like to proceed with a flyback converter:
* You can ditch the diode in series with the BJT.
* Replace the BJT with a MOSFET (100V / 10A should suffice)
* Output diode must be fast-recovery diode. SiC carbide diode should do wonders.
* The primary...
There are ways of adding inductive element on the same core; however, those are not easy to implement.
An inductor will limit the current only in current-control mode. In such a mode the duty ratio is dynamically changed to maintain constant input/output current.
The volt-second balance must be maintained on all windings. Otherwise, the voltage component would have a DC component and your transformer will quickly saturate.
What you can do is to use a rectifier secondary topology for non-flyback converter:
1) Half-wave
2) Full-wave
3)...
What's difficult about pulse transformer design? The only problem is the usual high required turns ratio that allows quite large core flux leakage and thus leakage inductance proportional to magnetizing inductance.
Also, 80 kHz is a standard frequency for power converters.
This is false. Once a voltage is applied across a transformer winding, magnetic flux starts increasing in the entire core, producing voltage on all other windings. Voltage is the time derivative of magnetic flux divided by number of turns. Since materials are not perfect, their do not possesses...
To my understanding the two approaches are (and ought to be) equivalent in the end.
In the big picture we could:
1) Use the usual circuit model, set up differential equations, do a nightmarish trigonometry (or transform to vectors and then do complex algebra to get the result.
2)...
Ratch,
this also means that reactance is negative for capacitors and positive for inductors (e.g. -500 Ohms for a capacitor as suggested by sophiecentaur).
This pretty much boils down to this question:
Is reactance jX or X? According to Agarwal & Lang (MIT - Foundations of Analog and Digital Electronic Circuits, 1st Edition):
Let us examine first the power delivered to some arbitrary impedance Z =
R + jX by a sinusoidal source, as depicted...