The cooling tower fan vibrates heavily
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Our company has a cooling tower fan with a motor of 75 KW. The coupling between the motor and the fan is about 2.8 meters long. Initially, no frequency converter was used; after one was installed, we tried to set the frequency at around 25. However, when the frequency was set below 40, severe vibration occurred, and the entire top of the tower shook noticeably. We would appreciate some advice from experts. (The fan blades were replaced at some point; old and new ones are used together)
Is it caused by falling within the critical speed of the shaft? Check by going beyond that speed range
It seems that the issue is mainly caused by an unbalanced blade
If the blade is unbalanced, shouldn’t the vibration at frequencies above 40 be greater?
Hehe, it was modified to reduce energy consumption. This approach of changing the rotation speed takes into account the angle of the fan blades, the critical speed of the rotor, and the critical speed of the rotor at different blade angles. Typical technical upgrades require the involvement of manufacturers or professionals in the design process.
You’re right; managers only care about saving energy and reducing consumption, never considering the issues with the equipment itself. Once something goes wrong after those changes, they issue strict orders to find out what caused it.
:lol:lol:lol This phenomenon is usually called “three-stroke behavior”: hitting one’s forehead, feeling a feverish sensation in the head, and coupled with the temptation of commissions from sales – that’s enough to drive someone to do it! ； Clap one’s chest twice; when raising an objection, clap the chest to express one’s stance – that works! ! Thump thump thump on the thighs – things have gone wrong, sigh,,,,,. Some say it’s the fourth beat, which means it’s time to leave: lol. Here’s a suggestion for you: come up with an explanation for that frequency at which vibration occurs, and set it to the disabled mode – that way the problem will be solved. Getting the boss’s satisfaction is the best outcome, after all, one is just an employee. If you’re a business owner, you can kick him out and make him go away,,, for reference only. :)
You have experience; I’m still a beginner and don’t have that courage :lol
I’ve also considered this issue, but isn’t this threshold a bit high? Vibrations below 40HZ are already quite significant