Rotating Magnetic Field's and Inductors.

[picowatt]

Thinking about what you said,i went and had a look at my rotor again. So here is what i did-->i have marked the N and S to the left side of the magnets-not on top as the timing diagram looks--my mistake. I did this so as i could see the N or S in case the magnet lined up with the core when the transistor switches off--which it dose. So in actual fact,the transistor is switching of just before the magnet reaches the center of the core,and i would think the kickback current flowing through the coil would pull it to the center of the core. I will have to remove the marks i have on the rotor,and mark the center of the magnet in stead to confirm this.

But look at the two scope shots below--what do you notice about the kickback with and without the rotor?. Also lets think about what is happening here.

What scope shots?

The coil is providing the energy to spin the rotor. The rotor in turn changes the (yet to be determined)coil in some way,and this change reduces the P/in to the coil

Based on the original coil and test setup, and the two scope shots associated with that setup, with the rotor installed the rate of rise of the current is slowed, and as the on time is fixed, a lower peak current is achieved.  This reduces Pin.

We know the external magnetic field has to be changing with time,as a static external field dose not alter the P/in--this we seen in the second video. So we take some of the energy out of the coil to drive the rotor-the rotor in turn reduces the P/in-all while the P/out remains the same.

In the last video,we could clearly see that without the external alternating magnetic fields of the rotor,the coil !although receiving the very same P/in at the same frequency!,dissipated much more heat than it did when the rotor was in play. We could also see that the output was less without the rotor,and this is a clear sign that the missing P/out without the rotor in play,was being dissipated as heat from the coil. So what is it that the external alternating magnetic fields do to the coil to reduce the dissipated heat from the coil,and raise the P/out from that coil.

If you had performed that test with the original coil (which I wish you would stick to), I would have predicted the additional Trise in the coil without the rotor merely based on the fact that the coil achieves a higher peak current without the rotor, as seen in the scope shots, hence more heat.

PW-this is what i mean by the magnets are converting the heat into electrical power. If the magnetic fields of the magnets on the rotor are changing the operation of the coil,so as waste heat is reduced,and electrical P/in go's down,or electrical P/out go's up,then those magnets are doing work. You cannot change anything without work being done. Even when you change your mind,work is being done by way of electrochemical signals racing around in your mind. As funny as you may think that sound's,it is true.


Brad

There is less heat due to the lower peak current achieved with the rotor installed because of the slowed rise time.  That seems fairly straightforward.   

Back to the timing/strobe tests, I am not sure what you are saying.  Do you know for certain what is happening when? Try using the original coil and test setup and use the second channel of the FG to drive the strobe.  You will then be able to shorten the strobe pulse and adjust its phase so you can see more timing detail.  For example, set the strobe to come on just as the coil turns off, etc.

I would think any portion of the on time or flyback period that occurs after the rotor magnet reaches TDC would decelerate the rotor and allow recovery of some of the energy that was stored in the rotor's inertia during acceleration.

See if you can determine exactly where TDC is in relation to the coil drive/current waveforms.

PW

[tinman]

Based on the original coil and test setup, and the two scope shots associated with that setup, with the rotor installed the rate of rise of the current is slowed, and as the on time is fixed, a lower peak current is achieved.  This reduces Pin.

If you had performed that test with the original coil (which I wish you would stick to), I would have predicted the additional Trise in the coil without the rotor merely based on the fact that the coil achieves a higher peak current without the rotor, as seen in the scope shots, hence more heat.

There is less heat due to the lower peak current achieved with the rotor installed because of the slowed rise time.  That seems fairly straightforward.   

Back to the timing/strobe tests, I am not sure what you are saying.  Do you know for certain what is happening when? Try using the original coil and test setup and use the second channel of the FG to drive the strobe.  You will then be able to shorten the strobe pulse and adjust its phase so you can see more timing detail.  For example, set the strobe to come on just as the coil turns off, etc.

I would think any portion of the on time or flyback period that occurs after the rotor magnet reaches TDC would decelerate the rotor and allow recovery of some of the energy that was stored in the rotor's inertia during acceleration.

See if you can determine exactly where TDC is in relation to the coil drive/current waveforms.

PW

What scope shots?

Oops-forgot to add the scope shots--see below.
This is from test two video,with the original coil.

[picowatt]

But look at the two scope shots below--what do you notice about the kickback with and without the rotor?. Also lets think about what is happening here.

Tinman,

Ah, those two scope shots.  Those are the two I was referring to.

What I see happening during the "kickback" is that the kickback voltage is clamped at approx 25V (Vbat1+Vbat2+Vdiode drop) in both scope shots for a fairly similar length of time.  Any current flow into the charge battery during the kickback portion of the waveform can only occur during the time the kickback voltage is at or above that approx 25 volts.  A CVR waveform of the charge battery current would provide more details regarding this, as we cannot readily determine the charge current from the voltage waveform.

The edge of the sine wave visible on the falling edge of the kickback provides a clue as to the position of the rotor magnet during the time current is flowing into the charge battery.  However, by the time the sine wave becomes visible, all current flow has ceased (except for leakage, etc).

I believe it most likely that energy is stored in the rotor via acceleration of the rotor during the coil on time and a small amount of that energy is recovered during kickback when the rotor is very briefly decelerated.

It would be a bit more informative if you could determine the precise location of the rotor magnet with regard to the various portions of the waveform.  In particular, precisely where in the waveform does TDC occur?

PW

[picowatt]

Tinman,

If you do further investigation of the rotor timing, see if you can determine exactly where both TDC and BDC occurs relative to the observed waveforms (with BDC being center point between magnets).

PW

[poynt99]

An observation from the two scope shots:

It appears that the reduced current during the ON time is a result of the negative-induced voltage in series with the battery voltage. I presume Pin goes down with the rotor installed.

So is there a problem or something that apparently hasn't been explained?