Muller Dynamo

[hartiberlin]

http://www.youtube.com/watch?v=YYRVwIw0azo&feature=youtube_gdata_player

This is a simular replication . It seems to run very long time on this supercap.

[Groundloop]

For those of you that want to build an "old fashion" 7 segment LED
based RPM counter to your Muller project.

All HW and SW files here: http://home.no/ufoufoufoufo/RPM.rar

Attached is a image of my built and tested first prototype version.
The printed circuit board can be cut in two to get a more easy
mounting of the display part.

GL.

[Tudi]

about litz. I think what romerouk wanted to say is that using he's home made coils made the wire coupling a lot more loose then using normal wire( just see a screenshot of he's coils ). Since the paralel wires in a core WILL generate an oposing magnetic force on each other and will try to cancel out each other ( thus the oscilating circuit definition ), having a loose wires will allow the coil to store more energy ( less loss / slower oscilations inside the coil )

Skin effect = larger distance between wires = less loss

Ofc, this has a specific formula at what distance you start to loose mor ethen gain. The magnetic field drops faster then with a linear formual depending on the material it propagates. You have a magnetic field from the permanent magnet, and you want to use this as much as possible. So you have a goal to put as much wires in this field as possible. But you also want to use loose coupling to reduce the "skin effect" => you see there is a middle way.

Since these days using uber magnets is something you can aford, I think it would be more advised to use a "flat and loose" coil instead of a long and close winded.

Yes i know there is a skin effect definition that relates to current strength versus voltage. I'm just trying to translate what romero might have wanted to say.

[lanenal]

Various rod sources may explain the variability in the placement of romerouk's stator magnets and why he needed to adjust them independently. 
Consistent core material may yield a more uniform post tuning arrangement.

Good observation. From the rod material, it might also explain why attraction mode is better: because the rod is probably near saturation with the helper magnet on the stator, and repulsion needs the driving coil to further strengthen the magnetic field but clearly the strengthened magnetic field will be clipped/plateaued by the saturation effect, therefore the efficiency won't be good. But with attraction, the magnetic field in the rod will need be reduced by the driving coil, there is no problem of clipping by saturation, the efficiency will be good. However, caution must be paid: even under the attraction mode, the rod should not be saturated when the driving coil is activated, otherwise the efficiency won't be good because the driving coil will spend some of its induced field to counteract the part of the magnetic field that is above the saturation point (the clipped part must be neutralized first). This probably explains why Romero says when the "helper mags" are too close it will be less efficient too.

In summary: the magnetically biased ferrite rod should not be saturated. If it is near the point of saturation, then the driving coil should work in attraction mode. If the ferrite rod is way below saturation, repulsion mode might work just as well as attraction mode.

[lanenal]

In summary: the magnetically biased ferrite rod should not be saturated. If it is near the point of saturation, then the driving coil should work in attraction mode. If the ferrite rod is way below saturation, repulsion mode might work just as well as attraction mode.

About magnetically biasing the rod: people here still remember the Flynn Motor? Basically, the principle one can learn from there is this: when magnetic field were "added" together, the magnetic force usually are not just "added" together, the total effect will be much larger. Then by biasing the rod, it is like magnifying the magnetic force resulted from the driving coil (as an electromagnet) by a multiplier greater than 1. This could be a factor that contributes to the overall COP. Of course, there are other possible factors, as many here have already been discussing. It is too early, but with those ideas it might direct us towards tuning...