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

[gotoluc]

So there is something seriously wrong.
Are you sure that you have the point A connected to the negative terminal of C2 ?

I think I see the problem now. Point A was connected to C1 as per you schematic, but the negative leg of C2 was on the other side of the CSR.  However, this means the flyback will be going though 0.05 Ohms of resistance and waste a little .

I'm just not use to looking or using schematics

I'll try it now and post the new shots

Luc

[verpies]

However, this means the flyback will be going though 0.05 Ohms of resistance and waste a little .

Yes, but negligibly at 0.05Ω. The up side is that this configuration allows you observe the current pulse charging the recovery capacitor C2.
Later, when all the measurements are done, you can remove the CSR from the L1, D1, C2 circuit ...or remove it altogether.

[gotoluc]

Okay, sorry about the schematic screw up.

Please find the new shots. First is with the rotor then the next is without and below is the same but with math.

Thanks for your help and interest

Luc

[verpies]

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.

[itsu]

I setup the circuit as in the below diagram, only i still have all 8 magnets facing north to the coil.
I use a 555 timer to sync the rotor with, presently running at 50Hz @ 31% duty cycle (12V input).

So i put the scope ground points as mentioned in the diagram (point B)

See screenshot 1 for a running situation, screenshot 2 with the rotor stopped (coil inbetween 2 magnets).

Blue is the CSR voltage (0.1 Ohm @ 1%) point A to ref. B
Green is my current probe set at 500mA/div. taken next to the CSR
Purple is the drain voltage point C to ref. B
yellow is the cap voltage point D to ref. B  (not shortend/emptied)


The DMM across the cap showed 5.8V when running, and 5.9 when stopped.


Regards Itsu