Sharing ideas on how to make a more efficent motor using Flyback (MODERATED)

[poynt99]

That is a very interesting phenomenon that does not occur very often.

When the PM aligns the domains in the same direction as the coil's current, then the apparent inductance decreases.
However, when the PM aligns the domains in the opposite direction as the coil's current, then the apparent inductance increases.

In other words, the inductance is measured relative to the equilibrium level of the domains.
The equilibrium level is the level of domain polarization to which the domains return spontaneously, when the current in the coil falls back to zero.

When the PM polarizes the domains one direction and the coil's current - in the opposite direction, then more headroom is created to accept the energy delivered by the coil before saturation occurs.
Without the PM, the coil can polarize the domains only from 0 to some maximum positive domain polarization.
With the PM, the coil can polarize the domains from some negative domain polarization to the maximum positive domain polarization - that increases the headroom a lot.

While analyzing such problems, it is useful to be mindful of the distinction between the "differential permeability" and the "absolute permeability" of the core and the entire magnetic circuit.
Actually it is about the non-linearity of the BH curve and the directional opposition of polarization vector components, but let's not split hairs.

Sounds like you read my post.
http://overunity.com/16261/rotating-magnetic-fields-and-inductors/msg470331/#msg470331

[verpies]

Sounds like you read my post.
http://overunity.com/16261/rotating-magnetic-fields-and-inductors/msg470331/#msg470331

No, I didn't but evidently you were first with this line of thinking.

Magluvin also:

So when we pulse a coil on the rod core with dc, we are only able to use half of the magnetization curve of the core. But when we bias the core with a magnet, with biasing in the opposite polarity of what the coil produces when pulsed, we now have access to the full magnetization curve of the core. By doing so we get almost twice as much ampere turns capability from the same coil/core with magnet bias vs without the magnet.
And it also increases inductance..  Its in the book.

[MileHigh]

Note in essence it's a zero sum game.   If you reverse the current flow through the coil, the inductance is decreased.

[gotoluc]

That is a very interesting phenomenon that does not occur very often.

When the PM aligns the domains in the same direction as the coil's current, then the apparent inductance decreases.
However, when the PM aligns the domains in the opposite direction as the coil's current, then the apparent inductance increases.

I'm glad you find it interesting and so did I when I saw it back in 2011.
Now, is there a way we can use this in our favor before they remove consumer access to Finmet cores?

BTW, I have your circuit on a project board ready to test.
Do I need any caps on the MIC4451YN mosfet drivers chip?
Will the 5vdc input be enough for the MIC4451YN mosfet drivers to switch the mosfet's on?

Thanks for your help

Luc

[poynt99]

Let's have some fun and put this to bed. You up for a challenge Brad?

I challenge you to an efficiency battle using only flyback from a coil. You stick with your iron core coil and rotor of magnets, and I'll use whatever coil I choose, but with no rotor, and no resonant tank. What do you say?

Let me know if you're up for it, then we can agree on some goals for the challenge.