Takashi Nagayama

AIR-COOLED TYPE INDUCTION MOTOR FOR USE IN VEHICLES HAVING MEANS TO REDUCE EXHAUST AIR NOISE

The air-cooled type induction motor used for railway vehicles such as the electric car generates sound waves (noise) which are uncomfortable to the ears of the human being when it is rotated. An induction motor according to the present invention has therein a plurality of waveguide (or air guide) plates for efficiently exhausting air, which serves to cool the motor, outside the motor. These waveguide plates are arranged not to resonate with the frequency of the sound waves which are generated by the cooling air. The sound waves are guided outside the motor through the waveguide plates before it is amplified to a noise level which is uncomfortable to the ears of the human being. Noise caused when the motor is rotated at high speed can be thus eliminated.