Muller Dynamo

[hartiberlin]

Hello Stefan,
I also have the same dc to dc convertor and I did a test for you. Up to 12v input, the dc to dc convertor puts out what you put in. So if you put in 5v it puts out 5v. Only up until 12v input, it starts regulating it to a fixed 12v output. So if you put in 14v it will put out 12v. So there is no "under voltage cutoff"

Hi Nali2001,
many thanks for the test.
COuld you maybe do another test by putting around 10 Ohms as a load resistor
to the output and then use a 47000 uF cap charged to 15 Volts at the input as
the input of this DC2DC converter and let us know, how long the LED will be
on and how the voltage at the 10 Ohm resistor goes down ?

Many thanks.

Regards, Stefan.

[i_ron]

@all,
I did some thinking and simulations on the driving coils.
It seems there are two interesting options:
1) connect them in series
2) connect them in anti-series

Option 1, series:
BEMF, induced by the rotor magnet, adds up for each driving coil.
The pulse source needs to compentate for the BEMF, or even over drive the BEMF to get some effect.
The cores will likely stay out of saturation, causing both cores to be attracted by the rotor magnet.

Option 2, anti-series:
BEMF is cancelled out.
The upper coil core will stay out of saturation
The bottom coil core will get into saturation.
Causing only one core to have a clear attraction by the rotor magnet.

So, either use the setup in attraction or repelling, each of this will have benifit if the right coil connection is chosen.

[editted]

Edit: deleted, no interest

Ron

[hartiberlin]

Hi Stefan, Tinu,

I have the exact same DC-DC converter and the LED is bright from 3-9V DC with output open circuit. Current draw open circuit is around 18mA.

Hope this helps.

Many thanks.

So the question is now, what does this DC2DC converter do,
when it has about 13 to 20 Ohms load on it.?

As RomeroUK had at 12 Volts 0.9 amps draw into his driver coils,
that means that it was a load of about 13 Ohms at this RPM he used.

in his last video:
http://www.youtube.com/watch?v=jzO0-p0NF7E

at minute 0:14 you see that also the DC2Dc converter LED is on
although the RPM is pretty low.
So  that means, that the LED is still on down to 3 Volts as Hoppy
confirmed..

So does it take about 43 seconds that the DC2DC converter
will drain the 15 Volts charged 47000uF cap to 3 Volts down ?

[lumen]

Hi Nali2001,
many thanks for the test.
COuld you maybe do another test by putting around 10 Ohms as a load resistor
to the output and then use a 47000 uF cap charged to 15 Volts at the input as
the input of this DC2DC converter and let us know, how long the LED will be
on and how the voltage at the 10 Ohm resistor goes down ?

Many thanks.

Regards, Stefan.

I believe the battery charging diode may have also been left in place, so some of the rotor generation would continue to feed back into the output of the DC/DC converter until the rotor stops spinning possibly keeping the LED on.

[Nali2001]

Hi Nali2001,
many thanks for the test.
COuld you maybe do another test by putting around 10 Ohms as a load resistor
to the output and then use a 47000 uF cap charged to 15 Volts at the input as
the input of this DC2DC converter and let us know, how long the LED will be
on and how the voltage at the 10 Ohm resistor goes down ?

Many thanks.

Regards, Stefan.

Hi Stefan,
I only had a 440000 uf cap.
So I charged it to 15v and with 10ohm on the dc to dc (set to 12v)
The led stayed on for 3 seconds. (resistor was smoking)

Without the resistor it takes about 26 seconds for the led to die down.

This is what the dc to dc output wire looks like btw.