Please help with an issue. My fan started vibrating with no load. I can't determine the heavy spot. I tried spinning the drum so that it stopped with the heavy spot at the bottom, and placed a weight on top. After this, the drum no longer stops with the heavy spot at the bottom, the vibration improved slightly, but it's still noticeable.

I inspected the bearings, replaced one because I found it loose. The vibration reduced slightly, but the vibration issue remains. How can I eliminate the vibration?

I considered buying balancing instruments, as I also have a mower and drying fans. I looked at some options under $5000: Vibromera, ADASH, ACEPOM322 (Chinese). What other instruments can you suggest?

Your method is known as static balancing, and it works well only for narrow rotors, like grinding wheels. Consider a wide rotor: one side has the heavy spot at the bottom, and the heavy spot on the other side is at the top. When you rotate it 90 degrees, these heavy spots balance out, and the rotor doesn’t turn with the heavy spot down. However, when you start spinning it, these heavy spots generate centrifugal force, leading to vibration. This is called couple imbalance, and it is only fixed by dynamic balancing, as it doesn't manifest in static balancing.

Recently, I ordered drive shaft balancing of my truck using the Balanset device, all without needing to remove it. Initially, I skeptically used clamps to temporarily attach the weights, unsure if it would solve the issue. To my surprise, once the vibration vanished, I permanently welded the weights in place. In summary, the Balanset device proved to be a reliable solution—it's cost-effective, efficient, and performs flawlessly.