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

[itsu]

i hooked up my 8 magnet (all north up) one coil pulse motor like in this diagram (12V from a battery):
http://overunity.com/16261/rotating-magnetic-fields-and-inductors/msg468654/#msg468654

Difference is that i have 1K across the flyback cap (1000uF) and using a MOSFET (IRF530)

I use my SG to switch the MOSFET (50 Hz) and measure the signals as seen below in screenshot 1

Blue is the gate signal referenced to ground
green is the current (probe) at the junction coil / drain 500ma/div.
purple is the drain signal referenced to ground

When using my SG to drive the MOSFET, i cannot hook up my probe ground to point C in the above mentioned diagram.

I have 22.42V in the flyback cap.
 
There is no difference when stopping the rotor, see screenshot 2.


Itsu

[verpies]

i hooked up my 8 magnet (all north up) one coil pulse motor like in this diagram (12V from a battery):
http://overunity.com/16261/rotating-magnetic-fields-and-inductors/msg468654/#msg468654

I was trying to adapt to Tinman's design when drawing that diagram, thus it was not optimal.

This circuit^* and probe hookups are much more preferable because:
- it allows the potential of the scope's ground to vary only minimally.
- the CSR also measures the current in the L1,D1,C2 circuit
- it separates I & V signals (Itsu's setup does too)

Anyway, your green current waveform is not showing strong signs of flattening out, so I judge that the pulse width is around 2*Tau.  That's better than most people do but still beyond the break-even point shown here.

Also, what is the current waveform induced in the coil measured in this circuit ...when the rotor is spun by hand (or motor)?

I have 22.42V in the flyback cap.

The 22.4V in the recovery cap is about correct.  The Source-Drain voltage waveform shows a peak close to 40V and with 12V power supply that gives 40V - 12V = 28V and the difference from 22.4V is probably wasted between pulses in that resistor in parallel with the cap.


Cheers

^* iso-drivers and double MOSFETs are optional

[gotoluc]

OK, that shows me classical inverted exponential current waveform for an LR circuit. 
Was the magnet attracted to the coil's core when this was taken...or was it away from the core? - I am asking because of saturation concerns.

The magnet was far away from the core.

Also, the voltage should be constant while the transistors are ON.  Since it is not (it is sloping down), I must assume that R_{DS_ON} of these MOSFETS (or wire resistance) is allowing for this voltage drop.

Part of the cause of the voltage drop on the above scope shot is the power supply is limited to 3 amps. Even though I have a 100,000uf tank before the switch my DMM displays a voltage drop when the switch closes. So I added a second power supply and it helped a little. See below new scope shot. However, the current is so demanding (without the magnet rotor assisting) that I have nothing else available that can mantain the 2vdc when the switch closes.

I expected most ringing when the transistor shuts OFF, but that is not the case because D1 starts conducting and keeps the current flowing trough L1.
The CSR does not show this current because it is not in the D1, C1 circuit. 
So the question remains: When does it start ringing after a delay and what determines this delay. D1 stopping conduction.

Anyway, when this current waveform is superposed on the current waveform obtained in this circuit while the rotor is moving, the result should yield the current waveform when the stator is powered externally, while the rotor is moving.

If it does not, then you have an anomaly.

I'll look at this in time.

Are you open to moving the CSR and the scope probes according to the schematic below, to clear these questions?

Yes I would be but unfortunatly I've already built another test device and removed the coil and 1 inch cube magnets from the rotor.
Lets see what the next test device does with the new CSR.
Btw where would the scope grounds be located?

Thanks

Luc

[verpies]

The scope grounds are marked on the schematic with little letters G on black background (photo negative)

[tinman]

i hooked up my 8 magnet (all north up) one coil pulse motor like in this diagram (12V from a battery):
http://overunity.com/16261/rotating-magnetic-fields-and-inductors/msg468654/#msg468654

Difference is that i have 1K across the flyback cap (1000uF) and using a MOSFET (IRF530)

I use my SG to switch the MOSFET (50 Hz) and measure the signals as seen below in screenshot 1

Blue is the gate signal referenced to ground
green is the current (probe) at the junction coil / drain 500ma/div.
purple is the drain signal referenced to ground

When using my SG to drive the MOSFET, i cannot hook up my probe ground to point C in the above mentioned diagram.

I have 22.42V in the flyback cap.
 
There is no difference when stopping the rotor, see screenshot 2.


Itsu

Itsu

Is it hard to change every second magnet in your rotor to south up ?.

It is good to see that even with the all north up rotor,there was no energy cost to spin your rotor as MH seems to think there should be.


Brad