If we know all parameters like inductance of coil, time of shorting , time of disconnecting, voltage of the source and capacitance of capacitor - can we compute the end voltage on capacitor as a function of current in inductor exactly at the end of Toff (disconnect time) ?
Yes, if the resistive losses are neglected (e.g. because the transfer of energy from the coil to capacitor happens very quickly) then the final voltage in the capacitor will be V = i*SQRT(L / C)
I wrote about this
here.
Verpies, you posted about the timing 0.5757tau where tau is R/L constant.
Oh, the nuances of the English language.
Tau is a "time constant" in the equation but it does not mean that Tau is constant in all circumstances.
In fact the Tau "constant" can be variable if inductance (L) or resistance (R) changes in time, because e.g.: a soft ferro core moves closer to the coil or the wire heats up, respectively. That's what parametric systems are all about.
Does the equation E=L*I^2/2 energy stored in magnetic field always apply , also in the 0.5757tau time moment ?
Yes, but it should not be named that way. It is the energy stored in an entire coil/inductor system (not only in its H magnetic field).
This distinction is meaningless in an air coil, but as soon as a soft ferro/ferrimagnetic core is introduced in the neighborhood of the coil, then the polarization of the domains inside that core (M) also has to be accounted for.
That is why I like to think of the ½Li
2 as the total magnetic energy of the coil system.
If Toff is short (less then 1/4 of the period of resonant frequency of LC) - like 0.5757tau , how to compute the amount of energy transferred from coil to the capacitor and the final voltage ?
Also by using the relation V = i*SQRT(L / C) where "i" is the instantaneous current flowing in the coil at the moment of disconnect.
If you cannot measure this current then you can calculate it from the
Transient State equations of the Circuit theory.
Let assume that the coil is connected in series with power source so the generated EMF add to the power source in moment of disconnecting.
That is an imprecise assumption because you did not write what type of the power source it is, e.g. a constant current or constant voltage power supply.
Such power supplies have very different internal impedances. Depending which one it is a coil in series with it, is either powered or shorted.
Nontheless, the energy stored in the coil system can be recovered and returned to the power supply.
I do it all the time in my lossless clamps circuits, which return the energy of switching spikes to the power supply, instead of wasting them as heat in RC snubbers or Transorbs or Transils or Zener diodes, etc...
See the schematic below (the orange windings and C3, C4, D3, D4 form these lossless clamps)
Verpies, are you willing to continue your essay about inductor energy transfer http://www.overunityresearch.com/index.php?topic=2684.msg43692#msg43692 ? 
Yes.
If you want to help, divide E
L by E
R and graph it in time (expressed in Taus)
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Topic: Flux Gate Interrupter, BEMF Redirector (Read 335740 times)
