Muller Dynamo

[mondrasek]

By the way I agree with itsu you should change probe1 and ground...

I also agree.  But you know I am no expert with an o-scope.  Still, it showed me what I was looking for.  Sorry for hooking it up wrong.

My build is sailing along with 3 pairs of mono-filer coils at 120 degrees.  No noticeable harmonic /resonance now on the acoustic side.  Very smooth.  But I have the coils far enough away that I only have 6 V ptp on each single coil.  After the FWBR and with all three in parallel it can raise the unloaded cap to 5.16V.  Not too bad overall IMHO.

I swept a load from 390 down to 50 Ohms in the increments that I could make with the resistors I had at hand.  I noticed an anomaly when I graphed it and double checked a specific resistance range.  The first pass I was only recording the resistor's stated value, but on the recheck pass I put them on the meter.  After a bit of double checking I found that the results in the narrow resistance band (130~140 Ohm) that I was checking was not repeatable.  So I assume this anomaly was just due to a vibratory resonance in the system that I cannot hear or that my bearings truly have a problem.

Anomaly aside, the graphs of resistance vs. RPM and resistance vs. o/p V are NOT linear.  I'm not sure about the relationship of rotational inertia and output V (no I measured) on this type of system, so I welcome any analysis from the group.

Still thinking about the next test.  Any input is appreciated.

M.

[slapper]

hi mondrasek. i hope you don't take this as any criticism because you are first rate on the mechanical physics of things. your input on this thread is greatly appreciated.

it's just that out of all of the scope shots yours appears to be the closest match to romerouk's.

can you please double check how you have your full wave bridge connected to your circuit.

thanks.

take care.

nap

[mondrasek]

hi mondrasek. i hope you don't take this as any criticism because you are first rate on the mechanical physics of things. your input on this thread is greatly appreciated.

it's just that out of all of the scope shots yours appears to be the closest match to romerouk's.

can you please double check how you have your full wave bridge connected to your circuit.

thanks.

take care.

nap

No problem at all.  I have 3 hooked up identical right now and paralleled.  How would you like me to double check?  Would a picture be best?

M.

[chalamadad]

Hi everyone, been following this thread for some time. Also trying to replicate. Thanks to everyone for contributing and sharing the experience. (new at this but learned alot already!)

Here is something interesting. Made three scopeshots.

1. is no load, just loading cap.
2. is running a small motor from the cap. Rotor doesn't slow down sigificantly. When the wave is going down you can see it's sawtoothed. Hint to resonance?
3. is shorting the coil by reed switch. Coil is ringing, resonance waveform is displayed. (There are two images overlapping cam is too slow, repainted the interesting part below.) Rotor slows down. Voltage peaks over 200V on meter if measured w/o cap connected. If connected, cap voltage goes down. 

I am putting in 6V and there is only one generator coil connected. Fills the cap to +7V. With small motor (as load) running still 3.5V in cap. When holding the shaft (increasing the load) of the small load motor amp draw goes up and cap empties. When it's empty the rotor slows down.

Is this good? Am I on to something here?

[slapper]

No problem at all.  I have 3 hooked up identical right now and paralleled.  How would you like me to double check?  Would a picture be best?

M.

ok thanks. in your schematic, reply #4134, your bridge is not connected to the circuit correctly, conventionally speaking.

your output(?) cap is connected across what normally would be the ac input and your coils are connected as the dc output.

thanks again.

nap