The sounder is used to check the size and sound quality of the rolling sound of the running bearing. Even if the bearing is slightly peeled off, abnormal sounds and irregular sounds are emitted, which can be distinguished by the sounder. Using auditory to identify irregular movements is a very common approach. For example, using an electronic stethoscope to detect abnormalities in a part is often a method used by experienced operators. 

1. If the bearing is in a good continuous state, it will make a low humming sound. If a sharp voice is heard, the voice and other irregular sounds often indicate that the bearing is in a bad transition condition. Sharp squeaking noise can be caused by improper lubrication. Improper bearing clearance can also cause metallic sound.

2. The indentation of the concave track on the outer ring of the bearing causes vibration and produces a smooth and crisp sound.

3. If the knocking flaw caused by the installation also produces noise, the noise will vary with the speed of the bearing.

4. If there is intermittent noise, the rolling parts may be damaged. This sound occurs when there is a contaminant in the bearing when the damaged surface is crushed. Severe co-response damage can create irregular and huge noise.

5. Bearing damage can be detected by hearing, but usually the bearing must be replaced immediately. Therefore, a better method uses, for example, an skf electronic condition monitoring instrument. Compared to the old method, a wooden stick or a screw is used to abut the bearing housing and the other end is attached to the ear. The new invention ensures a safer and more accurate estimation of the bearing condition.