How to judge fault by listening to the sound

This takes a lot of effort, without long-term experience accumulation and diligent summarization of good skills.* Habits cannot be judged accurately.

During normal operation, first use the listening needle to listen to the sound under normal operation to deepen your impression. When you hear sounds that are different from normal, there may be a problem.

This needs to be accumulated slowly in daily life, and you can tell when abnormalities occur by listening more.

Listen once every hour when inspecting the equipment on duty for a year. You will know whether the pump is running abnormally without anyone's guidance.

* Once you get used to it and get familiar with it through experience, you will know how to do it, but you just have to be careful.

* It becomes natural if you get used to it. Use the stethoscope stick to listen to the sounds in key parts. If you listen to more normal sounds, you will be able to hear abnormal noises clearly. a little experience: If you don’t bring a stethoscope and the noise at the scene is too loud, you can wear earplugs when listening to the sound. Don’t plug them too tightly to filter out some noise, and then listen to the sound of the machine and pump, which will be clearer and more comfortable.

I think we must first master the structure of the device, then know the operating frequency of each component, and finally analyze and judge based on the sound (of course this requires time to accumulate experience). For example, the bicycle you are riding now has a fast, sharp, metal-like abnormal sound of "cluck, cluck, cluck" (because you are specifically riding it, so you know that the sound is abnormal), then you can first look at it without looking at it with your eyes. You can first rule out that the sound is the collision of the brake pad and the wheel hub (because the brake pad is made of rubber material). Secondly, you can rule out that the small marble in the front fork is damaged, and it cannot be the chain and the cover (because their rotation frequency is relatively slow). The only remaining moving parts are the front, middle, rear axles and flywheel. You can make further judgments based on the location of the fault sound. . . . When you go to a car repair shop to repair your car, you can compare your judgment by observing the area where the problem occurred. I think as long as you have this thought, if the bicycle makes abnormal noises in the future, you will be able to accurately determine the fault location immediately. Isn’t the bicycle you are riding just a running machine? !

The noise in the pump body is mainly loudest outside the outlet of the turbine shell. It reflects the sound of the impeller running and in contact with the medium. It can be inspected to see whether there is cavitation in the pump.； If the bearing is short of oil or the components are damaged, it will also make abnormal sounds. ； Motor noise is mainly caused by whether there is a lack of grease, whether the motor cooling fan is experiencing abnormal friction, whether the fan blade connection is detached, etc.