Rotor Passing Through Critical Speed with Assistance of Electromagnetic Damper

Active electromagnetic damping technology has plenty of advantages, such as convenient parameter setting, fast response speed, suppression of vibration in a wide frequency domain, and so on. In this paper, an electromagnetic damper with PID controller is designed and assembled. Function of shock absorption and effect on rotor passing through critical speed are studied respectively under different combinations of damper parameters. Response behavior of the damper under static conditions is obtained experimentally through data acquisition board after applying displacement impact to the damper mandrel. Then, the damper is installed to the rotor test system set to accelerate to the first-order bending critical speed, at which vibration response of the rotor is investigated. Results show that the form and effect of the damper attenuating the displacement disturbance and whether the system passes through critical speed smoothly or not are all restricted by setting of damper parameters. Under specific parameter combinations, the effect of the electromagnetic damper on passing criticality has shown to be better than that of the oil film damper. Moreover, a controller with additional zero and pole pairs connecting in series is proved to be able to further optimize the response behavior of the rotor-damper system in low frequency region. Through the experiment, effectiveness of design function of the electromagnetic damper is proved, which provides a reference for the selection of the working parameters and a research basis for further optimization of the damper.