NEMA Releases Standards on AC Power Drive Systems

March 21, 2005 by Jeff Shepard

The National Electrical Manufacturers Association (NEMA, Rosslyn, VA) released two standards that are adaptations from IEC standards. The ICS 61800-2-2005, "Adjustable-Speed, Electrical Power Drive Systems, Part 2: General Requirements-Rating Specifications for Low-Voltage, Adjustable-Frequency, AC Power Drive Systems," and ICS 61800-4-2004, "Adjustable-Speed, Electrical Power Drive Systems: Part 4: General Requirements-Rating Specifications for AC Power Drive Systems above 1,000 Vac and Not Exceeding 35 kV."

Both documents contain amendments to identify those specifications in the original IEC standard that are not applicable in the United States. The ICS 61800-2 addresses performance requirements only; safety requirements are contained in other documents. Both standards contain tutorial information and terminology to enable practical application of the devices. The standards specifically address line harmonics and motor considerations.

The ICS 61800-2 may be purchased for $105 by visiting; the ICS 61800-4 may be purchased for $123 by visiting