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

[MileHigh]

Fantastic work like usual Itsu.  If I can suggest something it would be to not bother reversing some of the magnets in your rotor.  They are glued in place and there is nothing to be gained and nothing to be learned by doing all of the work to reverse them.

For you scope traces, this time after taking a one-minute look, I cannot see any appreciable differences between the two waveforms.  However, your multimeter is showing slightly higher voltage across the capacitor which is telling us that slightly more current is being drawn by the drive coil when the rotor is stopped.  This is to be expected because there is no influence from any counter-EMF in the drive coil from the moving magnets in the spinning rotor.

With respect to attempting to measure the added power that has to be pumped into the drive coil to make the rotor spin, that could be done.  However, that would require some thought and careful preparation and developing the right measurement regime to detect it.  Right now what is happening is that when the rotor is in place and spinning, the reduced current draw due to the counter-EMF induced into the drive coil is overshadowing the extra power that is added to make the rotor spin.  In other words, the preliminary analysis is that more current draw is reduced due to the counter-EMF than the extra current draw that is required to make the rotor spin.  There are two opposite effects that are happening at the same time with respect to the current draw and it is not necessarily that easy to separate them from each other.

[gotoluc]

It looks much better now. The downward ramp, that illustrates the current flowing into the recovery capacitor (C2) is clearly visible.  If the capacitor was empty, then this current would be a half of a sinewave.
There is still some oscillation at switch-off but that must be caused by the by the lack of starpoint wire connections.

Now it would be good to scope be voltage across the capacitor as it is rising from 0V (even after manual discharge), and if you have more than 2 channels on your scope, then that could scope that voltage simultaneously between points B and D (ground clip on B just like the other channels) with the downside of the small CSR's voltage drop getting added.  Pulsing the MOSFETs only once will make C2 measurements from 0V, easier.

Okay verpies, you should be happy with the below scope shots as C2 is drained to 0v before the next on time.

C2 is now a 60uf motor run cap and has a 47 Ohm 10w resistor across it.
The DC motor is not connected (assisting) in this test.
Input is still at 20vdc

Also, the switch off is much cleaner, see last shot.

Thanks for your help

Luc

[citfta]

Fantastic work like usual Itsu.

For you scope traces, this time after taking a one-minute look, I cannot see any appreciable differences between the two waveforms.  However, your multimeter is showing slightly higher voltage across the capacitor which is telling us that slightly more current is being drawn by the drive coil when the rotor is stopped.  This is to be expected because there is no influence from any counter-EMF in the drive coil from the moving magnets in the spinning rotor.

With respect to attempting to measure the added power that has to be pumped into the drive coil to make the rotor spin, that could be done.  However, that would require some thought and careful preparation and developing the right measurement regime to detect it.  Right now what is happening is that when the rotor is in place and spinning, the reduced current draw due to the counter-EMF induced into the drive coil is overshadowing the extra power that is added to make the rotor spin.  In other words, the preliminary analysis is that more current draw is reduced due to the counter-EMF than the extra current draw that is required to make the rotor spin.  There are two opposite effects that are happening at the same time with respect to the current draw and it is not necessarily that easy to separate them from each other.

MH,

Did you read what you wrote?  You just posted that the magnets are generating more power back into the coil than the extra power it takes to turn the rotor.  That has to mean the system is more efficient with the rotor than without.  I am amazed you can't see that.  Every single person that has done this test for you has shown you that either the rotor made no difference (only one as I recall) or in all other cases the input power went down.  I just don't understand how you can keep saying adding a rotor is not making these systems more efficient.

And by the way you never did comment about why so many industrial motors now have permanent magnets in them since you claim magnets can't do any work.

Respectfully,
Carroll

[MileHigh]

Carroll:

I appreciate your comments but I think that they will be more appropriately addressed after Tinman posts his test results in his thread, presumably in a day or two.  Then I will gladly pick up the discussion with you in that thread.

MileHigh

[gotoluc]

Carroll:

I appreciate your comments but I think that they will be more appropriately addressed after Tinman posts his test results in his thread, presumably in a day or two.  Then I will gladly pick up the discussion with you in that thread.

MileHigh

Thanks MH for taking that discussion somewhere else.

Regards

Luc