抄録
This paper introduces phenomena causing damaging torsional vibration of rotating machinery driven by Variable Speed Drive (VSD) Motor. Inter-harmonic frequencies contained in excitation torque generated by motor, because of its distinctive pattern, may coincide with natural frequencies of rotating machinery during operation even though the machinery was designed so that fundamental frequency and its harmonics can avoid coincidence with natural frequencies in the operating speed range. Torque of rotor shaft and output current of VSD were measured during product test. Quantitative guidelines for torque associated with sideband frequencies of VSD output current and modal damping ratio for VSD driven rotating machinery are proposed. Integrated mechanical (rotating machinery) and electrical (motor with VSD system) simulation was also conducted and its results were compared with measured data.
