Magnet coil cores, demagnetization power and Lenz delay.

[synchro1]

This is gibberish.

Hysteresis (from the Greek to lag behind). When retentivity of a ferromagnetic substance interferes with its re-magnetization in the opposite direction it (Lags behind).

[MarkE]

Hysteresis (from the Greek to lag behind). When retentivity of a ferromagnetic substance interferes with its re-magnetization in the opposite direction it (Lags behind).

Your post: 

Quote from: synchro1 on Today at 01:23:32 AM

    @MarkE,

    A rotor magnet passes a ferrite core and the magnetic field from the passng magnet transits from point A to point B through the core. What happens to the timee interval if we increase the magnetizem in the core? Why would anyone want to bypass all the conventional theories and jump to the Lorentz force to help solve this simple problem?

Is still gibberish.  Adding random references to hysteresis does not make it less so.

[synchro1]

OK so you've got a mag amp.  Those have been used for over a century.  Before the invention of thyratron tubes they were the method of choice for switching large AC power sources.  Under the right circumstances they only dissipate a small percentage of the controlled power.  The Steorn Orbo "core effect" motor is at its heart a mag amp operated device that only consumes net energy from its battery power source each cycle.

Now we have the basis for a formula: High core saturation yields increaseed electrical conductivity along with magnetic phase lag. Low core saturation delivers higher resistance to electricity and increased  permeability for magnetic flux change. This simple relationship is all we need know to understand the way magnets effect a ferrite core without resorting to an overly complex theory like "Lorentz force". No big deal MarkE!

[MarkE]

Now we have the basis for a formula: High core saturation yields increaseed electrical conductivity

It does no such thing.

along with magnetic phase lag.

It is just the opposite:  Saturated core = low inductance, introduces low phase lag in a series RL, or LC circuit.  Unsaturated core = much higher inductance and much greater series phase lag in the same series RL or LC circuit.

Low core saturation delivers higher resistance to electricity and increased  permeability for magnetic flux change.

The permeability is higher as is the inductance.  The resistance is unaffected.

This simple relationship is all we need know to understand the way magnets effect a ferrite core without resorting to an overly complex theory like "Lorentz force". No big deal MarkE!

Yes synchro1 it is no big deal, and relatively easy to learn.  Please learn it correctly.

[synchro1]

Let's take the Lorentz force situation first:

Just take two parallel copper wires each suspended between two posts.   Drive a current through each wire.  If the currents go the same direction, the Lorentz force between the wires pushes them apart.  If the currents oppose then the Lorentz force pulls the wires towards one another.  The delay between change in current in one wire and mechanical force applied to the other wire is s/(c*(uR*eR)^0.5)  Where: is is the distance between the two wires, c is the speed of light in a vacuum, uR, and eR are the relative permeability, and relative permittivity of the material between the wires.  As that material is air, uR and eR are for practical purposes both 1.0, and the delay reduces to: s/c.  If the wires are 10cm apart, the delay is about 333ps.  It would take very specialized instruments to detect the delay. For practical purposes in problems of designing electrodynamic machines like motors, or generators, we can safely treat the delay as zero.

Now change each wire to an air core solenoid.  Two effects result:  For any given DC current the number of Amperes per meter increases by the number of turns per meter.  This also increases the inductance of each lead so that the amount of time that it takes any given voltage to change the current in each lead has now gone way up.  However, all our materials still have uR and eR effectively equal to 1.0 so the electromagnetic field between each conductor assembly still propagates at the speed of light.  Any current change in one winding will be sensed as a mechanical force change on the other winding in a few hundred picoseconds.  IE for any practical motor or generator it is an ignorable delay.

Next insert a material with a uR of 1000 but highly resistive material into the solenoid cores.  Now the magnetic fields are far more concentrated by the permeability of the core material, resulting in much greater Lorentz forces and much greater inductance in the windings. The higher core permeability also slows the propagation of the E/M field through the radius of each of our solenoids.  Our sub nanosecond propagation delay over  is now in the ~10 nanosecond range.  That's still such a short delay that we would ignore it in any practical motor or generator.

Next substitute a core material with the same permeability but with a low resistance.  The magnetic field change in either core that results from any change in current in the winding induces eddy currents in the core.  Those eddy currents establish an image field that opposes the change in magnetic flux.  The external E/M field is suppressed.  The faster the changes in current, the more suppressed that field is due to the induced eddy currents.  If we step the current and hold it, externally the field builds-up as the eddy currents die down.  If the resistance of the core material is very low, like in ingot iron it can take milliseconds for the eddy currents to die down after a current step.  If the cores were superconductors, the eddy currents would never die down and the external field would never respond to the change in winding current.

This is the sort of thing that you have been talking about.  Note that what is happening is energy is put into the system, and the action of the eddy currents is to oppose that energy doing external work.  The eddy currents convert useful energy into heat.  They create loss.  They are a direct result of:  Faraday induction.  Their orientation is determined by Lenz' Law.  The induced eddy currents are not delayed.  The image field that they develop opposes the change in field that induced them and the external result is that the net field changes much more slowly than the applied current.

When you have digested the above we can move on.

This comment says absloutly nothing about magnetic phase lag in core material. This is just a phony punk showing off!