| Abstract |
A layer of air gaps has been included along the periphery of a conventional stator structure in order to
isolate the outer surface and reduce the noise emissions. The feasibility of this idea has been assessed
using structural FEM and acoustic BEM simulations. Results using different gap geometries show
that the overall acoustic behaviour of the new structures is not improved. On one hand, the stiffness
of the structure is reduced where the air gaps are introduced, since iron material is replaced by air. On
the other hand, it is shown that the vibrations are also transmitted through the air in the gaps,
providing less acoustic isolation than expected. These results, supported by experimental
measurements of a prototype motor based on the air gap concept, demonstrate that modern
computational tools can be used to assess the effectiveness of innovative ideas on the design of ‘quiet’
motors. |
