Technical and economical considerations in the application of variable-speed drives with electric motor systems

In the European Union (EU), variable-speed drives (VSDs) were identified as the motor systems technology having the most significant electricity savings potential. In the EU, the identified economic electricity savings potential with the application of VSDs, by the year 2015, in industrial and tertiary sectors, are 39 and 8 TWh/year, respectively. However, only a small percentage of this potential is being used. In this paper the characterization of the current market of the VSDs is presented, including the average prices, the installation costs, and the total sales in each EU country, per power range. Selected VSD applications are presented. The key barriers to a wider application of VSDs are identified. In particular, the power quality and reliability problems associated with the use of VSDs are presented and possible technical solutions are discussed.