Patent ID: 8669837

Claim:
A laminate stack comprising: individual involutely curved soft magnetic sheets each individual sheet comprising: a first long side, a second long side opposite the first long side, a first short side, and a second short side opposite the first short side, wherein the first long side comprises a recess, wherein when the individual sheet is in an uncurved state, said recess is rectangular and comprises edges that are equidistant from the first short side, the second short side and the second long side respectively; an inner section, having: an inside radius D i , and a front face having a surface A a , and a base having a thickness d, an outer section having an outside radius D a and a thickness c where d = A a π · D i ⁢ ⁢ or d = ( 2 · a + D i ) 2 - D i 2 4 · D i ⁢ ⁢ or d = D a 2 - ( D a - 2 · c ) 2 4 · D i .