Patent ID: 8240429

Claim:
An induction motor windage noise damping system, comprising: a motor having a housing, a cooling vent formed in the housing, a rotating shaft and rotor within the housing generating windage noise, and a cooling airflow path defined within the housing that is in communication with the cooling vent; a duct having proximal and distal ends defining respective openings and a duct airflow path there between, the proximal end opening in communication with the cooling vent and the distal end opening for communication with ambient air; a plurality of first baffles in the duct; a plurality of second baffles in the duct; and wherein the first and second baffles are oriented in an generally parallel mutually spaced array relative to each other and the duct airflow path, and wherein dimensions for at least one of baffle array parallel spacing, baffle thickness or baffle inset from one of the duct openings differ between the first and second baffles, and said dimensions are adjusted to restrict distance between adjacent baffles to less than a wavelength of windage noise at selected propagation frequencies between 400 Hz and 4000 Hz.