Custom Shaped Stator Core Laminates

[Alkemi]

Hello, I'm looking for laminated sheets, which I can stack together and make a core out of. I'm not looking for standard shapes. I'd like to make a core of custom shape using these sheets. I'll cut them per my need and then use in the motor I have designed.

I need to know where can I buy these laminated sheets? Any link or guidance will be appreciated. I'm in the US, but I'm willing to order from outside too.

OR

How can I make the core laminates at home as DIY project? If that's possible?

[MagnetJuice]

Can you tell us minimum size and the thickness you have in mind?

Ed

[Alkemi]

This is actually for linear motor. So the motor length is about 1 meter. Width 1/3 meter and thickness about 100 mm or so. So the lamination will be cut accordingly. For prototyping I don't mind the laminate thickness, but looks like 0.25 mm to 0.50 mm could be Okay.

[SparWeb]

Hi Alkemi,

These companies makes custom motor cores:
https://www.kienle-spiess.de/kspm.html
https://www.slmti.com/

However, they do it for professional and industrial needs.  They probably need an order of 100 or more before the parts and tools cost becomes economical.

If you just want to make a motor core/stator yourself, it can be done as a DIY project.  You could go about making the core profile you want in CAD and take the CAD file to a laser-cutting shop.  Depending on the shop, they may be able to help you find a source of material with soft iron and low cost.  The rest is surface treatments, assembly, and then winding a few miles of wire!

If memory serves, a former member of Fieldlines went pretty far in this direction: Peter Dingemans, "Dinges":
https://www.fieldlines.com/index.php?action=profile;u=3538

[MagnetJuice]

Alkemi, I found this, it is carbon steel sheets. I don't know if you can use it. Hopefully someone can lead you to a better stock of silicon steel that is better suited for your purpose.

https://www.mcmaster.com/steel-shim-stock

I did some research a while back not on linear motors, but linear alternators. In the future, when I have some free time, I would like to build a linear alternator to be powered by a stationary bike with a large flywheel.

If you don't mind, I would be interested to hear a description of your motor design.

I want to build a linear alternator using the same principle of an axial flux alternator. The only difference will be that it will produce the power from linear strokes instead of circular rotation. I want to compare the two different designs to see if there is an efficiency gain in one or the other.

Ed

[CraigM]

If you live near a larger city try looking at a scrap metal yard. When I lived in Phoenix AZ I found a yard that had shipping containers full of silicon steel scrap. Some pieces as shown in the photo were around 12" wide by 48" long.

Make a few phone calls to scrap yards and you may find just what you need at scrap metal prices.

[SparWeb]

Depending on what you want to accomplish, you could be looking for "the Best"
Carpenter is the metallurgy/foundry supplier that basically writes the standards:
https://www.carpentertechnology.com/en/product-solutions/cartech-hiperco-50-alloy/

Hiperco is specifically designed as a motor/transformer alloy.  Even if you probably don't want to spend on an order like this, you can learn from reading about this alloy (lots of literature). Then you can judge what you can get out of using low-carbon steel instead - and maybe it will do fine.

[Adriaan Kragten]

Stators of electric motors are laminated to reduce the eddy currents. The eddy currents flow in a direction perpendicular to the direction of the magnetic flux. Therefore there must be a thin isolation in between the separate sheets of the stator stamping. If you buy a stator stamping at for instance the German company Kienle and Spiess (they have a very good website and show all dimensions of the stampings which they supply), this isolation is already mounted in between the sheets but if you ask a company to laser cut sheets for you, you will generally get sheets without an isolation. You can't use any sheet material which can become magnetic. It is important that the iron loses its magnetism almost completely if no current is flowing through the coils. It must therefore be pure iron with a very low percentage of carbon. So sheets of stator stampings of this matertial are bending plastic already at a low bending stress.

[Alkemi]

Thank you all for your valuable comments/suggestions.

I was held up in another project and just finished it.

@MagnetJuice : About linear motor, I'm dreaming about the drone launcher platform based on linear motor track... Linear motors can achieve very high speed, so launching a drone using it as Gun is the concept. I'm still in design phase of it. Not sure I'd be able to get the speed, required for the launch.

@CraigM : Thank you for this suggestion, I'll try to find, if anything is available nearby DC area. It it's available somewhere far, I think, if they ship, I can order it.

[Alkemi]

Stators of electric motors are laminated to reduce the eddy currents. The eddy currents flow in a direction perpendicular to the direction of the magnetic flux. Therefore there must be a thin isolation in between the separate sheets of the stator stamping. If you buy a stator stamping at for instance the German company Kienle and Spiess (they have a very good website and show all dimensions of the stampings which they supply), this isolation is already mounted in between the sheets but if you ask a company to laser cut sheets for you, you will generally get sheets without an isolation. You can't use any sheet material which can become magnetic. It is important that the iron loses its magnetism almost completely if no current is flowing through the coils. It must therefore be pure iron with a very low percentage of carbon. So sheets of stator stampings of this matertial are bending plastic already at a low bending stress.

I know the Lamination plates/shims/layers are in perpendicular to the winding plane in all motors. Just curious to know what happens when they are in parallel to winding plane/layer? What's advantage, disadvantage of this setup (apart from manufacturing/assembly issue)?

[JW]

know the Lamination plates/shims/layers are in perpendicular to the winding plane in all motors. Just curious to know what happens when they are in parallel to winding plane/layer? What's advantage, disadvantage of this setup (apart from manufacturing/assembly issue)?

As science there talk this is a motor.

https://patents.google.com/patent/US8261575

[SparWeb]

Eddy currents.  As the field passes through any conductive material (not just ferromagnetic, any) the changing field generates an eddy-current that is at right-angles to the field passing into the material.  So if you put the N pole face against a block of aluminum, the field lines to straight into the aluminum block, so a circle drawn on the face of the aluminum block illustrate the path of the eddy in the aluminum.  That eddy absorbs a lot of energy so you want to break it up. 
If the lamination is edge on to the face of the magnet, then the eddies are very small (only passing across the thickness of the lamination).  If the aluminum block is solid, or the lamination is flat against the face of the magnet pole, then the eddy can be as large as it wants to be, and it will waste a lot of energy that the magnet could otherwise deliver into the field it's creating around itself.

[Alkemi]

Eddy currents.  As the field passes through any conductive material (not just ferromagnetic, any) the changing field generates an eddy-current that is at right-angles to the field passing into the material.  So if you put the N pole face against a block of aluminum, the field lines to straight into the aluminum block, so a circle drawn on the face of the aluminum block illustrate the path of the eddy in the aluminum.  That eddy absorbs a lot of energy so you want to break it up. 
If the lamination is edge on to the face of the magnet, then the eddies are very small (only passing across the thickness of the lamination).  If the aluminum block is solid, or the lamination is flat against the face of the magnet pole, then the eddy can be as large as it wants to be, and it will waste a lot of energy that the magnet could otherwise deliver into the field it's creating around itself.

Oh, that means if we change the lamination orientation from vertical to horizontal, then its as bad as having a solid core and not laminated core.

[JW]

I think "motor design" differs alternator design ?
I have one of these GE E20  Elec-Trak garden tractor

Im trying to figure out how to run a motor using SCR's

 kansaswindpower.net came UP which I find interesting.

https://www.kansaswindpower.net/GE%20ElecTrak%20Electric%20Garden%20Tractors.htm

 


 

[JW]

https://www.fieldlines.com/index.php/topic,149991.msg1050064.html#msg1050064

there's where the photo to my mower is.

[SparWeb]

Oh, that means if we change the lamination orientation from vertical to horizontal, then its as bad as having a solid core and not laminated core.

Yes.  That exactly it.

[SparWeb]

Here's a graphic to help everyone else visualize.
That eddy-current loop (in blue) can't form if the plate is replaced with a series of thin strips.