The background of verifying the vibration value of multi-stage centrifugal blower bearings and determining whether the blower bearings are damaged can be achieved through three dimensions: visual inspection, operation status observation, and professional instrument testing. The specific methods are as follows:

1、 Typical appearance and abnormal operating symptoms

Abnormal noise characteristics: Continuous buzzing sound, periodic shaking sound, friction noise, or resonance sound similar to a flute at a specific speed when the fan rotates, are typical signals of bearing raceway, ball or cage damage.

Functional abnormality: After turning on the device, abnormal noise is emitted from the glove box/fan compartment, the wind speed regulation fails and can only maintain low gear, and even internal short circuits occur, causing the fuse to melt.

Abnormal temperature rise: The temperature of the bearing area rises rapidly, exceeding 70 ℃, accompanied by obvious local heating, far exceeding the temperature range for normal equipment operation.

Vibration exceeding the standard: The effective values of vibration velocity in the horizontal, vertical, and axial directions of the bearing seat far exceed the qualified threshold of 4.5mm/s specified in ISO 10816 standard, and the amplitude exceeds 0.04mm.

2、 Simple manual troubleshooting method

Manual turning test: After power off, rotate the fan spindle by hand. If the rotation is stuck, there is a noticeable sense of obstruction, or if there is a loud friction noise during the rotation process, it can be preliminarily determined that the bearing is damaged.

Listening method investigation: Find a screwdriver, press the top of the screwdriver with your thumb, and place one end of the screwdriver against the bearing housing. Place your ear against your thumb and listen carefully for internal sounds. Normal bearings produce continuous and smooth raceway sounds. If you hear raceway damage sounds, ball impact sounds, or cage shaking sounds, it can be determined that the bearing is damaged.

3、 Professional instruments for precise diagnosis

Resonance demodulation method: Use a professional vibration meter to collect vibration signals, extract bearing fault characteristic frequencies through envelope analysis, and accurately determine bearing damage if there are obvious characteristic frequency harmonics corresponding to the bearing inner ring, outer ring, rolling element or cage in the frequency spectrum.

Oil analysis method: For bearings with lubricating grease, extract a small amount of old grease for iron spectrum analysis. If a large number of metal abrasive particles are detected, it indicates that severe wear has occurred inside the bearing.