Electric motor comprising an acoustic attenuation device

An electric motor, comprising:

• a frame defining an inner volume wherein is accommodated a rotor, a stator and a fan, the frame comprising:
• a first aperture placing the inner volume of the frame in fluidic communication with the outside of the frame, and
• a second aperture placing the inner volume of the frame in fluidic communication with the outside of the frame according to a radial axis perpendicular to an axis of rotation of the rotor,
• the fan being positioned in the vicinity of the second aperture and being configured for generating a gas fluid flow, wherein
• at least one acoustic attenuation device is accommodated in the second aperture so as to partly close the second aperture,
• the second aperture comprises at least one first passage and one second passage for letting through the gas fluid, the at least one acoustic attenuation device accommodated in and closing the first passage,
• the first passage and the second passage are defined at least partially by the frame and are adapted for the passage of the flow of the gas fluid between the inner volume of the frame and the outside of the frame,
• the first passage extends along a first radial axis, the second passage extends along a second radial axis different from the first radial axis, said first and second radial axis extend in a plane perpendicular to the rotation axis of the rotor, and the first passage and the second passage are circumferentially arranged around the rotation axis of the rotor, and
• the motor comprises a casing mounted to the frame, the casing comprising at least one soundless area arranged facing the first passage and not allowing the passing of the gas fluid, and at least one area arranged facing the second passage and allowing the gas fluid and the soundless area of the casing bearing the at least one acoustic attenuation device.