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darryl
11-08-2006, 03:25 AM
I was reading about one of the new breed of permanent magnet electric motors. Apparently it uses japanese silicon steel for the laminations because of its higher flux density, higher permeability, and lower iron losses. I have a couple applications in mind that would make use of these properties. Now I'm wondering how I can obtain some. In particular, I'm wondering what are my chances of being able to buy some from or through a local metal shop.

This would probably be called electrical steel, even if it is a more modern alloy. If I just asked for electrical steel, what are my chances of getting that? If this would be a stock item in some shop, what might the typical thickness of the sheet material be?

There are some alloys that would be better for my applications, like amorphous or permalloy, but I believe my chances at getting, or affording, a small quantity would be about as low as a pile of teflon coated marbles.

I haven't asked at any of the local metal shops. I doubt I'd get more than a blank look from anyone there, and I'm tired of chasing wild geese.
Where might I find a source?

Forrest Addy
11-08-2006, 04:06 AM
You're referring to "magnetic alloys" I think. There's a zillion kinds and it mostly comes in thin sheet and coil for punching into laminations. If you're looking for solid stock you're our of luck. It not only doesn't come that way it doesn't even work in that form. Your best sources are suppliers of macnetic alloys to the motor and transformer industry. Look them up in the Thomas Register under "Magnetics."

The Japanese and a dozen other nations have researched into this niche and come up with magnetic meterials having dazzling properties but here "dazzling" means modest annual improvements not the doubling of some vital characteristic.

The most effective and lowest loss magnetic materials are ceramics. They are non-conductive and thus have near zero eddy current losses. They do not have a high permeability and the magnetic traction available to a motor circuit are low making the motor larger for its torque.

The most profitable design for very high performance motors is still most likely a shell wound armature where only the winding rotates in the magnetic curcuit. My information is no doubt out of date but not that much. The most compact and powerful servoes in CNC machines are still AC not that much different from when their prototypes first appeared 20 years ago.