Simply put, a variable speed drive is a controller that allows a machine to run at different speeds depending upon automated input from an industrial process. That in turn provides the ability to provide smoother operations, and most importantly, energy savings by slowing down machinery when a process does not have to run at full speed. Long a leading book on this class of controllers, this new edition by industry authority David Spitzer will provide the latest improvements to variable speed drives, including automated 'smart' feedback systems. Readers with both basic and advanced controller knowledge will find this book to be extremely useful introduction to how variable speed drivers work, how they are best used, and what to do and what to avoid when employing them as part of an overall automated industrial enterprise, all with an eye on energy savings. The reader will find: * A basic overview of electrical, hydraulic, and instrumentation principles of variable speed drives * Coverage of the role that variable speed drives can play in overall plant energy requirements and energy savings * Coverage of developments in variable frequency drives * Coverage of new integrated manufacturing applications for variable speed drives * Newly added examples of real-world applications that help make the theory and knowledge more clear and understandable.