Stator core material for low rpm axial generator?

[lovetolearn]

Hello. I love this place! So many good, full answers everywhere!

I'm designing a windmill, aiming for the 800-1000 watt range. My idea is to build my stator core out of strips of steel, bent into circle. It will be perhaps 20 strips in concentric circles. My girlfriend works in a factory that makes little metal thingy's, so I should be able to get it cut into strips easily. But what material should I use?

I heard somewhere that 1006 low carbon steel is good. I can get 1008 pretty easily. I have found no information on the properties of these steels. I think I need low coercivity and high saturation.

Any help? Thanks!

Greg

 

[jbartos]

Suggestion: Visit

http://www.metrohitech.com/html/fans_menufecturing.html

http://www.ee.sc.edu/classes/Fall02/FECP2003/slides/Patterson_092302.pdf

http://www.iet.auc.dk/~aer/ironloss.pdf

etc. for more info

 

[lovetolearn]

Thanks jbartos... The third link was helpful. The first link is about the processes of factories that make fans. Second link is good concise theory. But I still haven't found anything about 1008 steel. The third link mentions some steels, but only by part number for a particular company. Are electrical steels standardized? Or more specifically, will 1008 steel work well for a generator core? The goal is a low rpm windmill.

Greg

 

[ScottyUK]

Try getting hold of the book 'Electrical steels for rotating machines' by Philip Beckley, published by the IEE in the UK.

http://www.iee.org/Publish/Books/Power/Po037c.cfm

This article might be of interest:

http://www.key-to-steel.com/Articles/Art101.htm

Try a google search on "electrical steels" or "silicon steels", including the the "".

Here's some possible suppliers:

http://www.aksteel.com/markets_products/electrical.asp

http://www.wcisteel.com/products/non.html

http://www.cogent-orb.com/

Hey! I've got more links than jbartos!!

Have you considered salvaging the stator and rotor cores of a machine someone else has already made, and winding it yourself for your application? You are going to need a lot of diverse skills to make it all yourself. Good luck!

 

[UKpete]

Industrial machines use "electrical" steels and these differ from regular steels because they have added silicon to increase their resistivity (and therefore reduce eddy current loss). They also have about 25% higher saturation flux density. So using electrical steels means that for the same power you get a smaller and more efficient machine.

However it is perfectly possible to use a low carbon steel in a machine such as yours (low speed) provided the laminations are thin enough, say 1mm or less, and provided you do not over-saturate it magnetically. Also note that laminations are insulated on one or both sides eg by steam blueing, or spraying with a resin.

I presume from your description you won't be having teeth as the core will be toroidal, and I guess you will use a permanent magnet rotor. In which case you have an airgap winding, and you need to keep the radial thickness of this as low as possible in order to keep the total airgap down.

 

[jbartos]

Suggestion: Visit

http://www.aksteel.com/markets_products/electrical.asp

posted by ScottyUK, and
focus on:
"Laser scribing TRAN-COR H electrical steels provides additional beneficial core loss reductions through domain refinement."
This process tend to be omitted by some steel manufacturers.

 

[jbartos]

Suggestion to lovetolearn (Electrical) Aug 30, 2003 ///\\Thanks jbartos... The third link was helpful. The first link is about the processes of factories that make fans. Second link is good concise theory. But I still haven't found anything about 1008 steel. The third link mentions some steels, but only by part number for a particular company. Are electrical steels standardized? Or more specifically, will 1008 steel work well for a generator core?
///Visit

http://www.kentuckyelectricsteel.com/products/carbon_steel.html

and ask the manufacturer for applications of 1008 electrical steel, and further treatments available.

http://www.cioinsight.com/article2/0,3959,1164670,00.asp

for a little story about 1008 versus sheet steel 10 Gauge HRS.\\The goal is a low rpm windmill.
///A good idea. It will last longer.\\Greg