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0066_Frame_C20.fm  Page 126  Wednesday, January 9, 2002  1:48 PM









                       Then, for T  , we obtain
                                y
                                T =  – M x∫  B ez dv +  M x∫  ( B exx –  B exz x) dv
                                                         z
                                 y
                                         v          v
                                                                                       1 2 
                                   =  M –   B z +  -----l +  1  2    1  2       1  2  -----l v
                                                            --R +
                                                                      --R v +
                                                   1 2
                                                                                  --R –
                                       x      B zx(  )x 24  B zy(  )y 8  B zz(  )z 8    B xx(  )z  4   12 
                                   =  – vM B z +  B xx(   1  2  1 2   +  B yy(  1 --R +  B zz(  1  2
                                                                    2
                                                   --R –
                                                        --l
                                                                           --R
                                         x       )z  4   8     )z 8     )z 4
                       Finally, we obtain the expression for T z  as
                                        T =  M x∫  B ey dv +  M x∫  ( B exy xB exx y) dv
                                                                  –
                                          z
                                                 v         v

                                            =  vM B y +  B xx(    1 2  1  2   B yy(  1  2 –  1  2
                                                                                 --R
                                                           --l –
                                                               --R –
                                                                        --R B yz(
                                                x        )y  8   4    )y 8   )z 8
                       Thus, the following electromagnetic torque equations result:
                                       T =  0
                                        x
                                                                           2
                                                          --R –
                                       T =  – vM B z +  B xx(   1  2  1 2   +  B yy(  1 --R +  B zz(  1  2
                                                                                  --R
                                                               --l
                                        y      x        )z  4   8    )z 8      )z 4
                                       T =  vM B y +      1 2  1 --R 2   –  1  2  1  2
                                                                       --R –
                                                         --l –
                                                                                 --R
                                        z     x     B xx(  )y  8   4    B yy(  )y 8  B yz(  )z 8
                       The electromagnetic forces are found as well. In particular, from
                                                       F =  M x∫  B exx v
                                                                   d
                                                        x
                                                               v
                                                       F =  M x∫  B exy v
                                                                   d
                                                        y
                                                               v
                       and
                                                       F =  M x∫  B exz v
                                                                   d
                                                        z
                                                               v
                       using the expressions for the expanded magnetic fluxes, e.g.,

                                           ∫  B exx v =  ∫  ( B xx +  B xx(  )x x +  B xx(  )y y +  B xx(  )z z) vd
                                               d
                                           v         v

                       and performing the integration, one has the following expressions for the electromagnetic forces as the
                       function of the magnetic field:
                                           F =  vM B xx ,  F =  vM B xy ,  F =
                                                                              x
                                            x      x      y     x      z   vM B xz

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