This book is written to share my knowledge and experience of over 40 years in the field of commissioning and trouble shooting of problems of hydro-sets in various projects in India, during the service period of BHEL and thereafter. Commissioning requires specialized knowledge of Excitation and Governing systems, Controls and Protections of the machine. However, some overall knowledge about the project involving main TG erection activities and other equipment like Transformers, S/Y etc. as well as civil activities of concreting and grouting related to machine foundations etc., is also highly desirable to achieve the goal of successful commissioning and O&M of the machine.