Jim Bryan
EASA Technical Support Specialist (retired)

The nameplate of an electric motor reveals much valuable information about the capability and performance of the machine. NEMA MG1-2014 (National Electrical Manufacturers Association Motors and Generators 1) and IEC 60034-8 (International Electrotechnical Commission) provide information required to be included on the plate to conform to the standards. 

This varies by the type and size of the motor. For instance, rated field and armature voltages are required for direct current (DC) motors but obviously are not required for alternating current (AC) motors. A table is included that lists the basic requirements applicable to motors. Not all motors will comply with these requirements. These include motors built before the implementation of the standards or outside the jurisdiction of the standards agencies.  Some motors, such as synchronous and wound rotor motors, will have additional requirements. To cover all these is beyond the scope of this article.

Topics covered include:

• Identification
• Power
• Maximum ambient
• Speed
• Phase and voltage
• Code letter
• Design letter
• Efficiency and service factor
• DC motors
• Power factor
• Altitude

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