Abstract: A muffler for an air-cooling system used for channeling air for cooling an electric motor comprises a housing mounted on the electric motor and formed with an air inlet; and an air outlet and an air passage extending between and connecting the inlet and the outlet. Air from outside the housing employed to cool the motor enters through the inlet, flows through the passage and exits through the outlet. Noise having a spectrum of frequencies including a relatively low main discrete frequency, which corresponds to a relatively long wave-length, and a plurality of higher frequencies is generated in the cooling air during operation of the motor and its cooling system. A baffle is positioned within the housing adjacent to the outlet to interrupt lines of sight from the air passage to the outside of the housing. The housing and the baffle are made of a metal or plastic and have sufficient mass to attenuate the higher frequencies of the noise spectrum to a substantial degree.

Abstract: The present invention provides an improved rotor and end connector for an induction motor. The end connector adjoins a rotor core. The rotor core includes a plurality of spaced ventilation openings and defines an aperture for capturing a motor shaft. The end connector should preferably surround and be concentric with the inner ventilation openings. To increase ventilation efficiency, the end connector has a plurality of spaced fan blades. Each of the fan blades has a sloping inner surface and backward curving outer surface. The backward curving outer surface is substantially perpendicular to the end connector, and directs air flow radially outward.