A chip international companies in Ningbo, Zhejiang province, 12 sets of pipeline pumps, on-site installation for air conditioning water system, there is a water pump noise value as high as 102 dB, the other 5 pumps have interval noisy, in 2021 has been to the factory reflect the noise problem, also send service personnel with a noise problem, through the way of grinding and polishing impeller mouth ring, Deal with noise. Now half of them have noise problems, and the owner directly suspects that there are problems with this batch of motors.
（一）现场检查噪音问题最严重一台 Site inspection noise problem is the most serious one
Noise phenomenon: when the motor is running normally, the noise is high. During the shutdown stage, there is a metal scraping noise.
Check the loosening of the fastening bolts between the pump, the motor and the base. Part of the gasket is in a free state. The reason is that the rubber pad is used for the gasket. (The scene picture is as follows)
When disassembling the motor, check the bearings at both ends of the motor. When disassembling the non-driving end of the motor, it is found that there is a lot of dust on the dust-proof outer cover of the bearing and the grease, and the grease is slightly emulsified by water. Bearing condition of driving end, no obvious abnormality. Dustproof seal ring and bearing seal cover are not damaged, dust and slight water do not exclude improper storage in the process of civil construction. (The following figure shows the non-driven end, which is taken after disassembly. The arrow points to a large amount of dust and grease emulsified by slight water)
The rotor of the motor, dust cover and other parts have not been found abnormal after inspection, as shown below:
Polishing impeller mouth ring and wear ring (the picture below is before polishing)
1, the pipeline pump using rubber pad block, rubber deformation, resulting in the installation of the pump, the pump is forced when the screw is tied, resulting in the distortion of the impeller during operation, resulting in the problem of vibration and noise. In addition, when the rubber is stressed for a period of time, deformation occurs and cannot be recovered, resulting in loosening of the locking screw.
2, in addition, the rear bearing water into a large amount of dust superimposed poor installation, resulting in this pump becomes the most serious noise.