Brushless DC-a modern approach to variable speed drives

The concepts of brushless DC and how it works are described. Similarities and differences with respect to other types of drives are discussed, and the use of the term brushless DC is justified, since many consider it simply a variant of the variable frequency drive rather than a separate type. The operating characteristics and parameters of brushless DC are compared to those of traditional DC drives in the small to medium horsepower range to 150 hp. Particular emphasis is placed on the advantages to the end user of the drive and how these advantages affect production, service, and cost to operate. Included is such information as efficiency, power factor, motor heating, and breakaway torque. Application benefits are discussed, demonstrating some of the advantages of brushless DC, given that it is inherently a digital system rather than an analog one