摘要 |
A rotor windage noise damping system for an induction motor cooling vent A duct having a duct airflow path has a proximal end opening in communication with the cooling vent and the distal end opening is for communication with ambient air. The duct includes a plurality of baffles. The baffles are oriented in a generally parallel mutually spaced symmetrical or asymmetrical array relative to each other and the duct airflow path. Dimensions for baffle array symmetry or asymmetry, parallel spacing, baffle thickness and baffle inset from one of the duct openings are chosen to restrict distance between adjacent baffles to less than a wavelength of windage noise at selected propagation frequencies, yet provide for sufficient cooling airflow through the duct. The duct may be tuned to dampen selected propagation frequencies by changing the baffle array. |