Alternator core material

[KatyDave]

What material would work best as core material in a high frequency (>250 KHz) 3-phase, permanent magnet alternator? Thanks!

 

[sreid]

You need to supply more information. PM alternator rotors are usually made from solid iron/steel. For high RPM operation, strength and retaining the magnets are usually the primary considerations rather than magnetic properties.

 

[UKpete]

At those very high frequencies obviously the iron losses are the main issue and you are at the extreme range of capabilities of electrical steel laminations. You will need to use 0.1mm I think, these are expensive. Surahammars Bruks and Spang are possible suppliers but I think the best material is from JFE in Japan, formerly NKK - they have a process to manufacture 6% silicon steel laminations using a diffusion process. Basically, the higher the silicon content the better from a losses point of view (it increases the resistivity).

http://www.jfe-steel.co.jp/en/products/electrical/index.html

There are possible alternatives to laminated steel: soft ferrites, powder iron or amorphous steel; ferrites have low flux density capability, powder iron (e.g. Hoganas) has high hysteresis loss and only moderate flux density, and amorphous steel is almost impossible to manufacture into a slotted structure.