Weather Protected Type I (WPI) - IP23
A weather protected Type I machine is an open machine with its ventilating passages so constructed as to minimize the entrance of rain, snow, and airborne particles to the electric parts, and having its ventilation openings so constructed as to prevent the passage of a cylindrical rod 0.75"/19mm in diameter.

Weather Protected Type II (WPII) - IP24W and IP44W
This enclosure is designed for use outdoors in adverse conditions and can be modified to include filters for extreme environments with excessive airborne particles. Air passage includes several abrupt 90 degree changes in direction plus an intake area or reduced velocity to allow solid particles or moisture to drop out before the ventilating air contacts active parts of the motor.

Totally Enclosed Air-to-Air Cooled (TEAAC) - IP54 or IP55
TEAAC provides isolation of critical motor components from the surroundings. The construction of this enclosure utilizes a top mounted air-to-air heat exchanger. External air is drawn in by a shaft mounted fan enclosed in a housing on the opposite drive end or blower mounted fan for larger frames. The air is forced through the cooling tubes at high velocity to promote efficient cooling and cleaning the tubes. Cooling is accomplished by circulating the internal air over the heat exchanger tubes where the heat is dissipated and the cool air is returned to the active parts of the machine.

Totally Enclosed Water-to-Air Cooled (TEWAC) - IP54 or IP55
TEWAC enclosure provides isolation of critical motor components from the surroundings. Consequently, it can be used indoors or out in clean or dirty environments. It is provided with a water-cooled heat exchanger mounted in top portion of the motor for cooling the recirculated ventilating air. Motor heat is conducted away by circulating water and not by discharged hot air, this it is suitable for confined areas. It is also the quietest of all available enclosures.