Totally Enclosed Fan Cooled - This enclosure is often supplied on smaller motors for compressors where isolation of critical motor components from the surroundings is required. Most of these designs use a round, cast-iron ribbed construction design, where the cooling air is pulled through the grill of the external shaft mounted fan and is directed over the frame fins by the fan hood. As mentioned earlier, TEFC motors are often less expensive than WPII within NEMA frame sizes. For smaller NEMA frame motors, TEFC enclosures are often less expensive than WPII enclosures, so be sure to compare during the selection process. If fine dust cannot be kept away from the motor, an enclosed motor should be used.
Sound levels are additive.
If a motor is rated at 85DBA, the overall compressor package will be at least 3DBA higher.