Motor enclosures fire, explosion hazards

Except for areas with fire or explosion hazards (hazardous areas), motor enclosures are designed to provide protection to the internal working parts. The development or improved insiilating materials and finishes has affec ted the required degree of protection and consequently the design and classification of enclosures. Examples of several types of enclosures are shown in Fig. 29-4. 

Fire or explosion hazards require special motor enclosures. Hazards include combustible gases and vapors such as gasoline dust such as coal, flour, or metals that can explode when suspended in air and fibers such as textile lint. The land of motor enclosure used depends on the type of hazard, the type and size of motor, and the probability of a hazardous condition occurring. Some available enclosures are explosionproof motors, which can withstand an internal explosion force-ventilated motors cooled with air from a safe location and totallv enclosed motors cooled bv air-to-water heat exchangers and pressurized with safe air, instrument air, or inert gas,... 

Energy Efficient (EE) Motor Designs, 628 NEMA Design Classifications, 630 Classification According to Size, 630 Hazard Classifications Fire and Explosion, 631 Electrical Classification for Safety in Plant Layout, 647 Motor Enclosures, 649 ... 

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