This standard is formulated based on the technical progress and development of hydropower units and the experience of bidding, design, manufacturing, installation and operation of large and medium-sized hydro-generators in the past 20 years. The main technical contents include: scope of application, reference standards, operating environment conditions, general technical requirements, overall structure, ratings and parameters, temperature and temperature rise, insulation and withstand voltage, electrical and operating characteristics, mechanical characteristics, thrust bearings and guide bearings, braking systems, fire extinguishing systems, cooling systems, excitation systems, detection systems, other auxiliary equipment, tests, nameplates, packaging, transportation, storage, trial operation and warranty period. SL 321-2005 Basic Technical Conditions for Large and Medium-sized Hydro-generators SL 321-2005 SL321-2005 Standard download decompression password: www.bzxz.net