Much of this information consists of standards defined by the National Electrical Manufacturers Association (NEMA). These standards are widely used throughout North America. In other parts of the world, the standards of the International Electrotechnical Commission (IEC) are most often used.
Nameplate Data Guide
Nameplate data is the critical first step in determining motor replacement. Much of the information needed can generally be obtained from the nameplate. Record all nameplate information; it can save time and confusion.
Important Nameplate Data
Catalog number
Motor model number
Frame
Type (classification varies from manufacturer to manufacturer)
Phase - single, three or direct current
HP - horsepower at rated full load speed
HZ - frequency in cycles per second. Usually 60 hz in United States, 50 hz overseas
RPM - revolutions per minute
Voltage
Amperage (F.L.A.) - full load motor current
Maximum ambient temperature in centigrade - usually +40°C (104°F)
Duty - most motors are rated continuous. Some applications may use motors designed for intermittent, special, 15, 30 or 60 minute duty
NEMA electrical design - B, C and D are most common. Design letter represents the torque characteristics of the motor
Insulation class - standard insulation classes are B, F, and H. NEMA has established safe maximum operating temperatures for motors
Code - indicates locked rotor kVA per horsepower
Service factor - a measure of continuous overload capacity