Muller Dynamo

[DeepCut]

colzilla, you should join Romero's forum :

www.underservice.org

DC.

[DeepCut]

It's running really nicely scorch. As far as power input to the SSG driver, i have run multiple coils from one SSG and got more RPM for less input when you get the timing between coils right.


All the best,

DC.

[wasabi]

Wouldn't there be an advantage to closing the magnetic circuit paths?
As they are configured now, the air provides a lot of resistance to the magnetic flux (reluctance) decreasing the efficiency of the whole system.

[Scorch]

Just another quick update.
Was able to get the current draw down quite a bit as the lubricant in the new bearings started to loosen up and 'break in'.
Now able to maintain 2,000 rpm, with coils only getting a little warm, and current draw down around 600ma. per SSG.
Of course some of that current is going back to the destination battery.

And, in response to Konehead, I have already completed some basic balancing.
At first I didn't think it was vibrating much because I couldn't really feel it by holding onto the dynamo at my work station.
But, then, I moved it to another room and started noticing that while the dynamo doesn't really shake, or walk across the table, the entire table, and floor, was amplifying the vibration.
So I did some balancing, not by adding weight but by merely drilling shallow holes, into the edge of the rotor, wherever it settles at it's low spot.
And this has helped significantly.

The best way to balance something like this is to use a pair of straight edges, on a level surface, then set the rotor, with shaft, across the straight edges.
The heavy side will always roll to the bottom. Then just mark it and drill, or grind, away some material. And I will do this the next time I take it apart.

I am most definitely going to want to upgrade to ferrite cores.
At 2,000 RPM I am only getting about 5.5VAC from one generator coil pair.
And I was surprised that, without cores, a backing magnet does nothing at all.
My first build (with larger coils that liked to fall off) had almost double the voltage just by adding one backing magnet. . .

So back to the workshop I go.
Have ordered some 1/4" X 10" Lexan disks to build new stator plates.
1/4" thick stator plate will allow my ferrite cores to be flush on the back of the stator plate and about 1/16" protruding from the coil faces.
5/16" acrylic, or Lexan, stator plates would be perfect but nearly impossible to find. . .

Will stick with litz wire, for now, since I have lots of it.
Plan to wind a whole new set of coils and will be a lot more precise this time versus just filling them up on the sewing machine.

Question: What is preferred for matched coil winding? Exact length of wire? Or exact number of turns?
Most coil specifications call for a number of turns but, unless using a precision coil winding machine, hand winding is not always layered perfectly.
So, it seems to me, the best way to ensure matched inductance is to make sure all coils have the exact, same, length of wire versus number of turns.

What do you think?

}:>

[Scorch]

I have run multiple coils, or even multiple windings, on one SSG.
With one trigger and separate transistors for each coil, or winding, but those always had an alignment, with the rotor, so everything triggered, at the same time, with each passing magnet.

In this case the timing is different. . .
If there is a way to operate two driver coils, triggering at different times, on a single SGG, do tell more!
Can you provide a schematic? How do you adjust the timing, between coils, on a single SSG?

}:>

It's running really nicely scorch. As far as power input to the SSG driver, i have run multiple coils from one SSG and got more RPM for less input when you get the timing between coils right.


All the best,

DC.