Bill (Professor) Drury 
Control Techniques Drives and Controls Handbook [PDF ebook] 

Variable speed drives and the associated electrical motors play a central role in industry as well as the buildings in which we live, work and are entertained. They are arguably the most potent tool we have in the quest to save energy and thereby reduce our carbon footprint. Their rate of development has been rapid and today”s product is in many ways unrecognisable from its ancestors of even twenty years ago. Development continues apace for the components used in the products, the products themselves and the ways in which the products are used.