Rotating Magnetic Field's and Inductors.

[tinman]

Brad:

>>> Magluvin referenced a book where a a coil with a ferrite core can be "preloaded" under the influence of an external magnetic field.  Considering in my example the two magnetic fields are 180 degrees diametrically opposed I think that will apply in this case.  It looks like when the coil first energizes it has to do the work to "clear out" the biasing of the core which is in the opposite direction that the coil wants to fire.  That sounds to me like it will increase the effective inductance - in this case.

I am talking about the simple controlled test that I described in my posting.  It's separate and distinct from your pulse motor so why are you making a connection when there is no connection?

Beyond that, I don't get that feeling or remember statements like that from you.  If you can show me where you said that that would be appreciated.

>>> On the other hand, if a static and unmoving magnet was "behind" the coil and biasing the core in the "right" direction, then when the coil was energized then in short order the core would get saturated and go "air core."  That sounds like it would reduce the effective inductance to me.  See?  You actually have to think these things through.

One more time, I am talking about the simple controlled test that I described in my posting.  It's separate and distinct from your pulse motor so why are you making a connection when there is no connection?

One more time, please go ahead and show me what you have been telling me.  Or are you just saying something for the sake of saying something with no context?

I assume that your frame of reference is your clips where you narrowed the pulse from the signal generator as much as possible so that the rotor was still turning.  This was done with your lossy coil.   I will just repeat again that has nothing to do with the controlled test that I described in my posting:

<<<<<<<<<<<<<<<<<<<<<<<,
For how it's happening, a simple test that anybody can do:

Suppose you pulse a fixed coil and it produces a north field that is facing the north end of a movable magnet:   

[S-coil-N]   [N-magnet-S]

So naturally the magnet will get pushed away when you pulse the coil.

Now, what happens if you have the coil open circuited and on your scope, and you pull the magnet away?

My expectation is that you will see an EMF generated by the coil that is opposite the applied voltage of the battery that you used in the first part of the test.

The conclusion:  When the battery pulses the coil, and the magnet gets pushed away, then the moving magnet will induce EMF in the coil that effectively reduces the voltage applied across the coil.  Even though you can't see it on your scope, it's still happening "inside" the coil.  That internal EMF opposing the battery voltage will reduce the rate of current rise when you energize the coil.  WOW - two things are happening simultaneously inside the coil.
>>>>>>>>>>>>>>>>>>>>>>>>>>>

So I would say that all the righteous indignation is misplaced and saying, "That's what I have been saying to you all along" is not even applicable considering we are discussing two separate things.   Nor can I recall cases where you say what you are alleging you said.   Lots of postings have passed under the bridge, so if you want to cite specific examples I will try to respond.

MileHigh

Post 270--The reduced P/in with the rotor is more to do with the induced flux into the inductors core,and not the induced negative voltage.

Post 676 on Luc's thread i also go into detail as to the possible !domain alignment. There are many more i have posted,but not going to waste time looking for them throughout both threads.

I would also like to repost a quote from your self MH.
Quote:   No, if anything, the presence of an external magnetic field should interfere with the core material's normal domain flipping and effectively reduce the inductance and therefore make the current waveform rise more quickly.

Well ,as we know,this is not the case. So this can only mean that your theories do not represent the effect that is taking place here. It is obvious that if this theory of yours is from your book's or known laws,then something is wrong with those known laws. It is obvious from your own quote that the inductance is not being reduced,as we do not see the  increase in the current wave form that you state should happen with a reduction in inductance--we see the opposite,a decrease in the rise time of the current wave form,which going by your own rules and laws means an increase in inductance.


Brad

[tinman]

@ MH

Now lets look at the peak current flow with and without the rotor.
Is it not clear that the peak input current flow without the rotor is higher than it is with the rotor--and yet,the peak current flow on the P/out side remains at the same value in both cases,but continues to flow for a longer period of time with the rotor in play,as can be seen by the dime duration on the yellow voltage trace.

So i ask once again,how can this be if it is not the inductance of the coil rising?.


Brad

[MileHigh]

You want to talk about the motor industry.  Then explain why these magnets that can do no work are now used in almost all small DC motors used in industry?  Why aren't they still using field coils?

Tesla is not mentioned for a very simple reason.  There are many who for whatever reason are rewriting history to reflect their agenda.  I did learn about Tesla in high school.  I learned of his fantastic genius and amazing engineering skills.  I am appalled to see how his name is misused today and only an extremely ignorant person would even attempt to minimize the great achievements he accomplished.

Regards,
Carroll

You take a motor and measure 100 electrical watts in, 95 mechanical watts out, and 5 watts of waste heat.  Now where do you think the power came from to make the motor output 95 watts of mechanical power?

Those are the facts.  If you willfully chose to ignore the facts I don't know what to say.

The average 25-year-old has probably never used a record player or a cassette deck.  They would consider CDs and DVDs to be "old technology."   They would not even know what a "vertical hold" knob is.  There is no rewriting of history with respect to Tesla.  He only did basic fundamental research, and then it was improved upon.  An average 30-something computer programmer has probably never written code for an 80386 chip or even seen one.  Times change.  There is no rewriting of history or "agenda."

MileHigh

[poynt99]

Let's say you are right Brad, that the apparent inductance increases momentarily. I believe that it is possible, and I posted to that effect. Let's say we are both correct, and both are happening at the same time.

Now what? What are you going to do with this information? What is the purpose of all this to begin with? If the purpose is simply to make the most efficient IK power source, then see below.

You up for my challenge? Here is is again:

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. 

[MileHigh]

Post 270--The reduced P/in with the rotor is more to do with the induced flux into the inductors core,and not the induced negative voltage.

Post 676 on Luc's thread i also go into detail as to the possible !domain alignment. There are many more i have posted,but not going to waste time looking for them throughout both threads.

I would also like to repost a quote from your self MH.
Quote:   No, if anything, the presence of an external magnetic field should interfere with the core material's normal domain flipping and effectively reduce the inductance and therefore make the current waveform rise more quickly.

Well ,as we know,this is not the case. So this can only mean that your theories do not represent the effect that is taking place here. It is obvious that if this theory of yours is from your book's or known laws,then something is wrong with those known laws. It is obvious from your own quote that the inductance is not being reduced,as we do not see the  increase in the current wave form that you state should happen with a reduction in inductance--we see the opposite,a decrease in the rise time of the current wave form,which going by your own rules and laws means an increase in inductance.

Brad

This is shorthand:

The reduced P/in with the rotor is more to do with the induced flux into the inductors core,and not the induced negative voltage.

Your point is valid but are you just expecting the readers to fill in the blanks?  Is it all so obvious?  Just using the term "induced flux" is potentially misleading because we are talking about the energy required to flip the magnetic domains in the core - but you are not stating that so I am not going to remember it as "the energy required to flip the domains."  Perhaps stuff like this is obvious to you when you are in your own technical and bench bubble - but it's not obvious to the readers.  You have to state things more clearly.

If we assume that both flipping the domains and the negative induced EMF come into play, I am going to guess that the negative induced EMF is the larger of the two factors.

I would also like to repost a quote from your self MH.
Quote: No, if anything, the presence of an external magnetic field should interfere with the core material's normal domain flipping and effectively reduce the inductance and therefore make the current waveform rise more quickly.

But that was a generic discussion, it was not a discussion about your motor.  You and Luc reported the same observation and agreed with the statement.  Then later on I qualified that some more and talked about the direction component of the vector addition, etc.  I also said that this situation has to be looked at on a case by case basis and you can't make a generic statement about the effect.  It's just another bait and switch.

Well ,as we know,this is not the case. So this can only mean that your theories do not represent the effect that is taking place here

That's another bait and switch.  I have stated about 10 times that when a coil pulses to drive a rotor the current waveform for the coil rises more slowly.

It is obvious that if this theory of yours is from your book's or known laws,then something is wrong with those known laws.

You are just going back to your comfort zone and playing the "laws" card.

MileHigh