Muller Dynamo

[Scorch]

1/25/13

In terms of a regular rotor with all magnets facing the same direction-
Should timing, or pulse width, of the driver coil even be a consideration with regards to the rest of the system?

Considering that when the driver coil 'fires', on one magnet, all the other magnets are in different positions approaching, or leaving, their respective coils.
So, other than trying to make the driver coil as efficient as possible, I don't think timing, or pulse width, is critical to the rest of the function of the generator coils or accomplishing a resonance in said coils.

In this offset system; the driver coil pair is completely independent of what other coils are doing.
So timing, or pulse width, of the driver coil might only have an effect on ONE of the generator coil pairs at best.
And timing might only be a factor with regards to operating TWO driver coil pairs as you may want one to compliment the other.

But even with two driver coil pairs; it may be best to just make them operate as efficient as possible including BEMF recovery.
Therefore something like an SSG driver circuit may be all that is needed to accomplish desired efficiency, RPM, and resonance in the generator coils.

Or am I totally off track here?

}:>

Probably the best way to go is to just do as the doctor ordered 'first'  Then modify from there if no good results.

You have the hard part done. How did Romero have his hall sensor? Its the little things, that mean a lot. 
Dont worry about drive consumption yet, just get the motor up to speed first, then work on getting better eff. by tuning.

Mags

[Scorch]

1/25/13

I didn't have to run any service calls today so I managed to throw together a new SSG driver circuit for the dynamo.
And I actually still have a few 2N3055 transistors so I used that, instead of MJL21194, because it looks cool and might actually perform a little better.
Hope I don't need to run a second driver coil therefor would have to build another. . .

That is all for now.

}:>

[Scorch]

Had it running today.

Was able to obtain 2,500 RPM without any major vibration issues.
Which is kind of surprising to me because this rotor is not nearly as true, and balanced, as it should be and the center hub is even a little bit offset so it's possible to see the rotor moving up, and down, a little bit when it's turning slowly. And even with the original, grease, lubrication in the bearings, it always stops in the same spot with the heavy side down.
So, this is the first time I have seen this run high at a high RPM and I pretty impressed with the mechanical performance even with all the defects and lack of proper balancing.

As it is, right now, I have to push the coils pretty hard to obtain this RPM and I still intend to continue making improvements.
The alignment of the rotor magnets is a little off as well. I must have screwed up a measurement somewhere because the magnets are not, quite, centered in relation to the coils.
I can see that I do want to go back to ferrite cores, with bias magnets, which is what this whole project is all about.
I can get get a few volts at higher RPM but there is still significant slowing under load.
And considering my current configuration is using well over two amps, just to maintain that RPM, this is not likely to get far with just air cores.

And I am questioning- Is litz wire even needed? I keep hearing this really isn't an advantage unless operating at high frequencies.
And ZFF said he managed to obtain resonance with his device which just had regular magnet wire.

So I am still trying to keep it as simplified as possible and I will, likely, just use regular magnet wire for another coil set.

The SSG drivers actually seem to work pretty good, are easy to build, and I have a full range of RPM control with the benefit of BEMF recovery which could go to a capacitor to supplement the generator output.
There is still a LOT I want to do with this. Including a better rotor, ferrite cores, improved coils, arduino control, etc, etc.

But I did produce a short video of this thing actually running.
See:
http://www.youtube.com/watch?v=WPVzV5Ewj8Q

That is all for now.

}:>

[Magluvin]

Hey Scorch

Do you have cores in the coils, or just the nylon hardware?

Mags

[konehead]

Hi Scorch
looks pretty good to me - good job so far...
you should have ferrite cores, or you probably arent going to get things happening with those backing- magnets behind the cores which is the really unique thing about the RomeroUK machines.
I think keeping the coils wound with litz wire is very good idea myself.   Litz wire is a must with anything high-frequency, and you can think of high frequency not just in HF pulsing-events or AC signal, but also flip-over events like quick  change of core polarity too, and backemfrecoil spikes too
start taking power out of your generator coils see what happens -  whole idea is to get that speed-up under load. and no braking under generator coil load, when pulling power out of the generator coils - this is done by positioning the backing magnets,  and these backing magnets not necessarily "directly" behind the generator coils, and not necessarily all facing same polarity too - only way to find out how and where to place your  backing magnets is when motor runs at certain rpm you finally choose to run it at, with all those generator coils hitting load...also stack the backing magnets up higher or lower in height to make them more or less strength too - this is other variable with the backing magnets besides the placement and the polarity they will face.
Try to take power out all at once, in all generator coils at once into same resistive load - this way its possible for the 9coils/cores vs 8 rotor magnets anti-rotational latching effect to influence the generator coils too, while they are loaded,,,there will be probably an rpm to not go past, as where the anti-latching effect of the odd vs even configuration will have no effect at higher rpms while at lower rpms it will help.
Its good to have the steel washers on back of your generator coils too, so the magnets will stick to it as you expereiment plus theu might help in the way the backing magnets affect the cores.
You should balance your rotor - its not that hard, just pound small pieces of lead into small rod-shapes, and drill hole in rotor and glue them in....use some bearings with all grease cleaned out so you have very little resistance when balancing rotor - I like to use very small tiny bearings when balancing.  Have the rotor horizontal, spin it amd see where it stops at, and so stick the lead-bits on rotor with masking tape until  your get if pretty close so it never settles same spot, spins for long time, and when it  doesnt have any "pull back" reverse rotation is good sign you have it balanced....once you get if balanced with the masking tape holding on the lead, then drill the holes and glue in the lead....you can use old battery terninals from cars for the lead. Its going to take 2 or 3 hrs to do good job balacing it but its worth it.
You should be able to make your motor coils about three times better (same rpms with less draw or same draw but more rpms however you want to look at it) when you put backing magnets behind the cores in the motor coils too...
you might be able to get the speed-up effects with aircores, but its going to be lots harder to do...its probably possible, but I havent seen or heard of it being done yet with aircores and magnets behind aircored coils..