Selecting ASD systems

This article covered a large number of issues that are addressed by the NEMA Application Guide for Adjustable Speed Drive Systems that must be considered for successful application of an ASD system. The material covered here should be helpful in bringing issues to light that may be critical for the application engineer to consider while creating an initial specification. It is clear that such a specification must consider the interrelationships between the driven load, the motor, the control, and the utility power supply. The authors believe that all users of ASD systems would be llserved by having a complete copy of the NEMA´s freely available application guide for ready reference when planning and installing a new ASD installation.