Synchronous Motors with Cylindrical Rotors for the Petrochemical Industry

Abstract

An important role is played by the compressor in the petrochemical industry. Typical high-speed compressor drivers are turbines and induction and synchronous motors. The cylindrical-rotor synchronous motor and its application as a high-speed compressor driver is discussed. Important tasks within the production processes of the petrochemical industry include gas liquefaction, compression, refrigeration, and heat recovery. Compressor drive systems constitute important components in plants for such processes. In the past, large high-speed radial and axial compressors were driven mainly by turbines, but in recent years electric motors have been used increasingly. In addition to lower plant costs, the advantages Include high operating efficiency, low pollution, and simpler handling and maintenance. The majority of drives are operating at constant speed, using a four-or six-pole motor with stepup gear. For large ratings, synchronous motors are preferred. For these a number of specific characteristics, such as electrically excited oscillating torques during asynchronous acceleration and special cooling conditions, must be considered. The urge for optimum operating characteristics has led to the development of the synchronous motor with laminated cylindrical rotor, derived from the two-pole turbine-driven generator. The design structure, the steady-state and dynamic operating characteristics, and the starting performance during asynchronous acceleration of such synchronous drive systems are the topics covered here. The theoretical background has been excluded from the normal text and is summarized in the Appendices.