Qingzhou Bangyuan Agriculture and Animal Husbandry Machinery Co., Ltd. took a three-phase asynchronous motor driven double-support double-suction centrifugal cooling fan as a research object.260 kWversus1487 r / min, The bearing model of the free side and load side of the motor are respectively3 G 3 2222. 3 G 3 2224 (3 G 126), The bearing models on both sides of the fan are1622, The elastic pin coupling is responsible for the connection between the fan and the motor.

Specific maintenance

Combined with the results of fan vibration value detection, it can be intuitively found that the impact value of the fan motor side bearing is abnormal. At the same time, the diagnosis is carried out based on the corresponding frequency spectrum characteristics. It can be confirmed that the bearing outer ring of the fan load side has more serious abnormal wear. The load side bearing method solves the abnormal vibration failure.

In order to clarify the cause of the failure, the maintenance personnel conducted a follow-up test of the cooling fan after maintenance, and found that during the measurement processEMC-2000BversusMCV-021There is a big difference in the measured results, this difference is more distinct in the vibration speed value on both sides of the fan, and because of8month10The fan has just completed the replacement of the free-side bearing, so the maintenance personnel preliminarily judged that the free-side bearing is improperly installed in the fan. The internal airflow is unstable, but during the actual inspection, the maintenance personnel found that the direction of the abnormal axial force confirmed by the actual survey is not consistent with the actual situation, and there is a wide gap between the end surface of the bearing seat and the free end bearing cover of the fan8 mmTherefore, it is confirmed that the fault stems from the installation center of the fan rotor is on the free side, and there is a situation where the bearing side of the fan's free side is much lower than the height of the bearing side of the load side. The resulting abnormal axial force affects the normal operation of the dust removal fan The result of this judgment was confirmed by on-site maintenance personnel.

However, after the installation of the coupling and the load side bearing of the fan was completed according to the standard, the maintenance personnel found that the end cover of the free side bearing seat of the cooling fan could not be properly installed in the bearing seat, and there was75 pxDifferences, from which a deeper analysis was carried out. The maintenance personnel confirmed that the fault originated from the inaccurate positioning of the fan installation foundation during the commissioning stage. The equipment historical maintenance file also proved this judgment. After realigning and adjusting the reference position of the bearing seat, The vibration value of the fan has reached an excellent standard, and the vibration problem has been solved. Until the publication of this article, the fan bearing has not failed.