Full definition
National Electrical Manufacturers Association — the US trade organization that publishes standards for electrical equipment including motors, enclosures, wiring devices, and power generation. Key NEMA standards for industrial applications: (1) NEMA MG-1 (Motors and Generators) — defines motor frame sizes (143T-449T), mounting dimensions, efficiency levels (Standard, Energy Efficient, NEMA Premium), starting characteristics (Design A, B, C, D), insulation classes (B=130°C, F=155°C, H=180°C), and service factors. (2) NEMA enclosure types — NEMA 1 (indoor, general purpose), NEMA 3R (outdoor, rain/sleet), NEMA 4 (watertight, indoor/outdoor), NEMA 4X (watertight + corrosion resistant — stainless), NEMA 7 (Class I hazardous, explosion-proof), NEMA 12 (industrial, dust/drip tight). NEMA standards are the primary reference for specifying motors in Mexico, the US, and Canada, where NEMA frame sizes (e.g., 184T, 256T) and efficiency classifications are standard purchasing criteria. IEC equivalents exist (IEC 60034 for motors, IEC 60529 IP ratings for enclosures) and are increasingly used internationally, but NEMA remains dominant in the Americas. For belt drive applications, the motor NEMA frame determines shaft height and diameter, which determines pulley and belt selection.