Gearbox spectrum by spectrum analysis typically exclude the possibility of common gearbox failure, combined with the previous analysis of the total amount of vibration, the vibration of the gear box found vertical and horizontal direction than the axial direction of a certain directional vibration, the vibration amplitude increases with the increase of the load, the more sensitive to changes in the load. Moreover, the high frequency component of the frequency of the vibration frequency is 5 times the speed of the vibration amplitude is very large. Thus, the gearbox has a resonance suspected possible. In order to further determine the nature of the failure of the unit, the need to address two issues: first, the forced vibration source is determined; secondly, whether the gearbox vibration frequency coincides with the 290Hz component.

Forced vibration source and determine the frequency of vibration. Forced vibration source is determined first disconnect the gearbox after the compressor, the motor running single drive gear box, for testing. Analysis of test data. Conclusion Based on the analysis of measures, due to the high speed shaft screw compressor drive shaft in the gearbox to send the compressor speed frequency five times lower incentive resonance, causing the unit to generate strong vibration, eliminating resonance eliminate resonance unit, is to take the natural frequency with the excitation frequency separated from the main methods are the following: (l) changes in excitation frequency, so that is no longer consistent with the natural frequencies of the machine or structure, that increase or decrease the speed of the screw compressor to avoid first-order natural frequency gearbox high speed shaft.(2) change the vibration frequency to eliminate resonance. May increase or decrease speed gearbox shaft mass (weight) or rigid, you can change its natural frequency. Increased rigidity may increase the frequency, while increasing the quality of the natural frequencies will be reduced, but before structural changes needed to make a complete analysis of the system is calculated. (3) at the outlet of the compressor installation of the damping buffer, the vibration of the compressor to relieve the gas pulsation excitation, thereby reducing the vibration of 290Hz to force the screw to produce an active, reducing the excitation of the gearbox driven shaft.