axial generator with lamination core

[mbouwer]

People are sometimes really driven to build a savonius.

[Bruce S]

The "mill" in that picture is not a true Savonius as it is set up.
Typical "S" types have the "buckets" overlapping.

Not sure that the one pictured would even stay up in a decant wind.

However, I do agree, some will go to strange lengths :-)

Cheers
Bruce S

[mbouwer]

What to think of Mingyang's new 22 MW concept?
Which transmission and generator will be used there?

[mbouwer]

What I read is that they use a medium speed gearbox and a permanent magnet generator.
Should we for diy also go in that direction with a small axial generator driven via an acceleration stage?

[Mary B]

What I read is that they use a medium speed gearbox and a permanent magnet generator.
Should we for diy also go in that direction with a small axial generator driven via an acceleration stage?

Would only be viable in larger machines... a 2 meter rotor would lose to much power in the gearing... have to balance tower needs(larger the rotor the more robust the tower needs to be!) against rotor size, and cost of both... sure step up to a 2 1/2 or 3 meter rotor, but then step up your tower design...

[mbouwer]

For example this small generator with a 2- stage gear chain drive mounted in front of it.

[Bruce S]

Very nice windings! What size is the wire?

Cheers
Bruce S

[mbouwer]

@ Bruce,
It's one of those small axial generators that you can buy on the internet for a price for which you can't make it yourself for.

[MattM]

Looks like Aliexpress.  Scammers.

[Bruce S]

@mbower
IF you still have the link, would PM me with it please?
I'm curious about the wire as it looks like it's either very thin wire, or flat wire.
IF it is flat wire, then it is not worth the time due to the same issues using flat wire that even the guru's from years past on here have had.
IF it is very thin wire, then the voltage will be interesting.
I'm also betting the 2-stage is an external step not internal to this built unit.

@MattM  I've ordered from Ali--express for years now and have always gotten what I ordered.
However, I always read and copy the description of the stuff I'm ordering and expect an answer from the seller long before I place an order.


Cheers
Bruce S

[mbouwer]

@Bruce,
Search for: 100 Watt DIY Micro Generator.



Should the iron core and the backplate consist of laminations?

[MattM]

Why go this route when they sell more similar to Piggott for either 9 coils at $100 or 12 coils at $110?  These tall coils look too deep relative to the DIY versions.

[mbouwer]

These coils have the great advantage that they have an iron core.
But I don't know what material the core is made of.

[MattM]

Sure looks like steel rather than simple iron.  They do leave the steel core open in their set ups.  Eddy currents need 2 dimensions to form.  The open cores removes depth to the steel.  You may get some eddies forming vertically but those should have minimal impact on cogging.  Metal under a moving magnetic field will still heat.  Is the open steel core able to cool off relative to the copper is the real question.  They have different expansion rates and the steel will expand 10x faster than the copper.

[mbouwer]

Isn't this just an axial version just like a radial version where there is a stator with teeth built up from stator sheet laminations.
The iron of the stator and the cores of the coils must be able to change polarity very quickly and must not become permanently magnetic.

[MattM]

It would be interesting to see if that was the case by mounting freely rotating magnets under each coil.  If a north magnet was above the coil then the magnet under the coil should rotate its south pole towards the coil.  But I believe that all the magnets interact simultaneously.  The magnetic fields and coils do not match in numbers, so in reality only one coil at a time should truly be under polarization.  The others are all in a state of transition.

[brandnewb]

Ok here goes nothing.

At my dear dutch brother in arms. Do you have a test bench to test several configurations?

I am still working on mine. Perhaps we can share notes on how to make a viable test bench.

After all I have come to trust that demonstrations are worth "1 million dollars wink with pinky at mouth" famous quotes dr evil. Austin powers films.

I propose that the sooner we are able to break out of hypothesis{1} or gut feelings, or leaning on notions or in general not really carefully looking into the matter at hand{1} with field data the faster we can help advance the field.
{2}perhaps this is not the correct thread to demonstrate the importance of this concept But I have been unable to demonstrate that stacking a specific type of magnets would result in a specific type on field increase. Even though it was generally assumed it would have been{2}

[mbouwer]

Small axial generator to build a working model of a windmill.

[mbouwer]

9 coils / 12 magnets.
According to the Bavaria Winding Diagram Table, 9 coils / 10 magnets would be a better combination.