Muller Dynamo

[toranarod]

I am trying to get a team together to replicate this . One problem with replication can be , do you try to exactly copy  the working example or do you use materials to hand to save money . I plan to compromise by building a good shaft and rotor and then experimenting with the other bits .
           Here is an important question . What is the orientation of the magnets on top of the coils? If we assume that all rotor magnets are north pole up , are the magnets on top of the coils north pole up or south pole up . Also I need to learn more about Hall effect switches .Obviously , the motor drive coil needs to be energised as a magnet approaches it , and switched off as the magnet comes to its closest point to the coil . I am not quite clear at the moment what causes it to switch off at this point .

I am doing both
for speed and diversity i am building with what i have in stock. and I almost have all the materials anyway. left for dozens of other projects.
will also replicate to the exact specification, thats a longer term project it will take a week or so to get stuff made and shipped in.
 

[toranarod]

just trying to get an idea of the wire required to wind the coils. this is based on 7 strands of .2  so .125 will be inside this figure.

[romerouk]

Hi all,

I see there are questions about the rotor being smaller that the magnets lenght.
I am not at home now to recheck but I know for sure that the rotor was made from 4  0.3mm discs.
During the initial building and testings I have changed the rotor, changed the magnets,... It might be a 1cm + 0.5mm magnets togheter, I remember having that on the rotor at one point, but I am not sure, I must check later.
I had to use the heat gun to take the magnets off, initially I dan them in NSNS configuration.
I had measured the inductance and it is 1.203mH plus and minus, not all coils are exact value but with the magnets on the rotor being close to them that might not be exact.

[alan]

What's the secret? The even/odd arrangement?
Is it really necessary to use litz wire?

[sigis]

Hi all,

I see there are questions about the rotor being smaller that the magnets lenght.
I am not at home now to recheck but I know for sure that the rotor was made from 4  0.3mm discs.
During the initial building and testings I have changed the rotor, changed the magnets,... It might be a 1cm + 0.5mm magnets togheter, I remember having that on the rotor at one point, but I am not sure, I must check later.
I had to use the heat gun to take the magnets off, initially I dan them in NSNS configuration.
I had measured the inductance and it is 1.203mH plus and minus, not all coils are exact value but with the magnets on the rotor being close to them that might not be exact.

Thank you RomeoUK,
I will wait for answer. Just be careful do not destroy working unit.
May I ask make oscillograms from motor coils to, also from couple of generator coils, and to measure amplitude and period of pulses.