The textbook presents a modified theory of vibration diagnostics of rolling bearings. The methods of technical diagnostics of electrical equipment insulation without high-voltage tests are given. The physical nature of the electric arc inside the tank of an oil-filled transformer is revealed for the first time. The methods of complex technical diagnostics of electric motors and power oil-filled transformers are described. Expert systems of technical diagnostics of electrical equipment are considered. Conditions of damage to cables by partial discharges are revealed. Meets the requirements of the federal state standards of higher education of the latest generation. The textbook is intended for students, undergraduates and postgraduates of energy specialties of universities, as well as for specialists in technical diagnostics of equipment of thermal and nuclear power plants, industrial enterprises.