IEEE Standard 1566: standard for performance of adjustable speed drives rated 375 kW and larger, was written to assist users, consultants, and manufacturers of large adjustable speed drives (ASDs). Users and consultants use it to specify a high-quality drive system and more easily compare proposals, while manufacturers easier to produce and compare. IEEE 1566 provides industry-wide alignment of terms that are commonly used in drive discussions as well as descriptions of various common drive functions and requirements.