Muller Dynamo for experimentalists

[nueview]

thank you woopy and lidmotor
i found this today after watching a you tube by lidmotor about the muller motor i have seen the effect staring at me but needed to have it jogged from my mind it is very interesting and will do a better vid again please watch it as it may help you all.

http://www.youtube.com/user/geshbeddin?feature=mhee

motor test 3
martin

[e2matrix]

Sounds great plengo!  Fascinating results you are getting.  Sounds like you are on the right track. 

[plengo]

my video with my second run test.

http://www.youtube.com/watch?v=pG3OshMBwrs

Fausto.

[EMdevices]

ALL,

I want to give you some insights that I have into this dynamo that might help you understand it better. 


1)  this generator conducts current into the output capacitor in short pulses, which come from each coil in a sequential order.   At 2400 RPM there are approximately 5700 pulses per second or a 5.7 kHz frequency.  This speed is higher due to the ODD/EVEN ratio of magnets to coils, and different sets of coils and magnets come into alighnment every 5 degrees of rotor rotation.

2)  the pulses occur around the maximum induced voltage, when the voltage increases ABOVE the output capacitor voltage.   RomeroUK's dynamo produced around 15 Volts unloaded, and 12 volts when loaded with that 12 volt light bulb,  and on the graph below I drew the red lines where this corresponds on the normalized curve.   (12/15 = 0.8 )

3)  notice that the flux is ZERO at maximum voltage according to the laws of electrodynamics, and the flux in this region of current pulses is linear (I drew thicker lines in this region)

4) However, the most important thing to note is the short duration of the pulses, approximatley 0.5 ms.   Why is this important?   It's because it is a shorter duration than the TIME CONSTANT of the coils when shorted, which is calculated as:   

tau = L/R = (5 mH) / (1 ohms) = 6 ms        (approximate, I think Romero said one coil was about 1.5 mH, and doubling the turns increases it by 4 times if coupling is 1, which gives 6 mH, but I'll derate it to 5 mH as an approximation, and 1 ohm resistance as an approximation)

and we know that it takes 4 or 5 time constants for steady state to be reached, where the magnetic induction stops and the voltage drop is all due to the resistance of the coil wire.

So what this is saying is that the flux interaction is very efficient and I^2 R losses are minimized or eliminated at higher speeds.

Design Guidelines:

1) Use big coils with lots of turns, that will give higher inductance and results in longer time constants.
2) Keep the coil wire resitance low, by using thicker litz wire or even solid wire if Litz is not available.  This will also result in longer time constants.
3) Faster speed is desirable, but with higher speeds more losses occur from air friction and bearing viscosity, etc.. however, the higher speed will compensate for a shorter time constant.
4) Biasing magnets reduce hysterisis loses in the ferrites as they cycle their magnetization.

EM

P.S.   Nice work Fausto,  I'm trying to catch up, winding coils this weekend.

[EMdevices]

Here's something that should raise your eyebrows!

With the light bulb load,  Romero has about 2 amps continuous current flow from the output capacitor.   The input to the capacitor is from the current spikes generated in the coils, but these are of short duration, so they must be much higher in current than 2 amps.    The duration of the pulses is approximately  1/10 the duration of one cycle, or the period T.    Remember the coils don't conduct current only when their voltage goes higher than the capacitor voltage plus the diode bridge forward voltage drop.


So to have an energy balance into the output capacitor,   we need pulses 10 times higher in current, or approximately 20 amps !


Now you should realize how important it is to use Litz wire or thick wires to handle the large current bursts.  Litz wire is better to handle the higher frequency and will have a lower AC resistance at the same frequency as a comparable sized solid conductor.  But you can use a solid conductor of thicker size, but then you will have a larger coil.   It's all about optimization and minimizing unnecessary losses.

Here's an approximate calcualtion of I^2 R losses in the coil:

(20 amps)^2 * (1 ohm) = 400 watts pulsed

so averaging over one period we get a continuous power loss of:

400/10 = 40 watts !

So this generator outputs 25 watts into the light bulb, and loosing 40 in the coils, for a total of 64 watts, but this lost energy is NOT COMMING FROM THE INPUT (12 watts), IT IS GENERATED FROM THE MAGNETS  ? 

If this is the case:   the COP is (64-12) / 12 =  4.3

This dynamo is actualy generating a net 52 watts out of "thin air."

So shouldn't this be COOLING DOWN THE MAGNETS SIGNIFICANTLY?

EM