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

[tinman]

At 1:40am here is the last update

Link to video: https://www.youtube.com/watch?v=Qt-eOxo6gjg

Thanks for your participation

Luc

Ah,and i see in this scope shot,there are no question marks after the results,and all the wave forms are within the screen.

[nightlife]

At 1:40am here is the last update

Link to video: https://www.youtube.com/watch?v=Qt-eOxo6gjg

Thanks for your participation

Luc

Nice but why not go further and utilize the flyback from second coil and the next and next until you have no more room for coils?
Another thing to check is magnetic strengh of each coil before and after each one is added.
Another interesting thing to check would be heat differences.

[verpies]

could you please do the calculations on my below scope shot.

The input is exactly 2.00 Volts DC
The CSR is 1% 0.1 Ohm
The Capacitor is 9.92uf (measured)

Your waveforms are pretty spikey due to long lead inductance and lack of starpoint connections, so I could not go by scope's automatic calculations and had to make my own.

600mV across a 0.1Ω resistor would mean that 6A is flowing through it.

So, the approximate energy delivered to L1 by the power supply is E₁ = 2V * 6A * 10ms * ½ = 120mJ  ( *½ because it's a triangle ).
The peak energy recovered by C2 is E₂=½CV² = ½ * 0.00000992 * 50² = ½ * 0.00000992 * 2500 = 12.4mJ

Thus the "backspike" recovery efficiency is E₂/E₁ = 12.4mJ / 120mJ = 10.3%

[Over Goat]

the "backspike" recovery efficiency is E₂/E₁ = 12.4mJ / 120mJ = 10.3%

is this 10% using just one coil, and could using ten coils you know what?

[itsu]

Quoting myself:We cannot trust the L₁ in the formula E₁=½L₁i² because L₁ might not be constant during the ON-pulse, when the rotor is influencing it.

However, if we use the difficult, albeit fool-proof method (V_inst *I_inst * t) of calculating the energy expended by the 12V power supply to bring L₁'s current up to 880mA, we get approximately 45mJ (from ½ * 12V * 1A * 7.5ms, when we assume ideal sawtooth current fitted symmetrically into the real curved-down current waveform - see below).
A Math trace of Ch2*Ch3 integrated between cursors set to the width of the ON-pulse, would give us a more precise number.

We can trust that the capacitance of C2 is constant, so we can trust the formula E₂=½C₂V²

Nonetheless the energy recovery efficiency form L1 into C2 is still E₂/E₁ = 56.18mJ / 45mJ = 1.25 or 125%   


So the first task for Itsu is to confirm, that the constant supply voltage applied to L1 through the MOSFET is really 12VDC and that PEAK current flowing through L1 is really 880mA  and that C2=10μF and that the CSR = 0.1Ω and that scope probe attenuation is set correctly (e.g.: x10).
The second one is to do the Math trace Ch2*Ch3 and to integrate it for the duration of the ON-pulse, to confirm the energy delivered to L1 by the power supply.

Hmmm,   i checked again the coil, and it measures 37.8mH @ 100Hz, the capacitor C2 measures 10.03uF @ 100Hz and the csr measures the mentioned 0.1 Ohm 1%, allthough
that is hard to confirm as my DDM is fluctuating in that low region, but after subtracting the leads resistance, it seems to be the correct 0.1 Ohm.

The battery voltage was/is 12.4V as can be seen on the screenshot below where i toke an input measurement of the battery voltage (12.4V yellow trace) and the
input current with my current probe set to 200mA/div.  This screenshot was in a stopped state, i appearently forgot to save the same situation when running, but i
remember the wattage calculation to be 35mW, so a difference of about 10mA between running (35mW) and stopped (44.78mW).

(Note that the current controller was set to 200mA/div, so the green current value and the wattage values need to be taken x 20, so in the below screenshot
158.6mA RMS current and thus 895.6mW)

Taking more samples did not change the Math mean value.

By the way i have seperated the 555 timer circuit input voltage and the GotoLuc circuit input voltage by using a different 12V battery for both.


I will try to redo that input measurement test, but it is clear that the input wattage increases from 700mW (35mW * 20) when running to 895mW when stopped.

I will also try to come up with the data requested by verpies.

EDIT   i have the input measurement when running on video which i will upload now.  There you can see what happens with the input power when stopping the rotor.
Also it shows that i have changed the R2 resistor again, now for a 50K pot which gives better control over the cap trace.


Regards Itsu