Important role of enclosure
The enclosure of the motor must protect the windings, bearings, and other mechanical parts from moisture, chemicals, mechanical damage and abrasion from grit.
NEMA standards MG1-1.25 through 1.27
define more than 20 types of enclosures under the categories of open
machines, totally enclosed machines, and machines with encapsulated or
sealed windings.1. Open Drip Proof (ODP)
Allows air to circulate through the windings for cooling, but prevent drops of liquid from falling into motor within a 15 degree angle from vertical. Typically used for indoor applications in relatively clean, dry locations.
2. Totally Enclosed Fan Cooled (TEFC)
Prevents the free exchange of air between the inside and outside of the frame, but does not make the frame completely air tight. A fan is attached to the shaft and pushes air over the frame during its operation to help in the cooling process.
The ribbed frame is designed to increase the surface area for cooling purposes.
The TEFC style enclosure is the most versatile of all. It is used on pumps, fans, compressors, general industrial belt drive and direct connected equipment.
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