What is a Balanced Fan? Think “Finishing the Job.”

A balanced fan must stay below specific vibration limits for safe operation while running at full speed. Excessive vibration will decrease the life of your fan and can lead to catastrophic failure.

Our factory takes the issue of balance very seriously. With our focus on building high-quality and reliable fans, every fan is designed to go through 2 stages of balancing – 1) dynamic balance and 2) trim balance.

Stage One: Dynamic Balance

Dynamic balance is required in accordance with standards established by the International Organization for Standardization (ISO). At this stage, we balance the wheel by itself, and it’s referred to as two-plane ISO dynamic balancing.

To accomplish this, we suspend the fan wheel between a center-hung shaft and run it at about one-sixth of the maximum operating speed, dynamically balancing it until we achieve the maximum imbalance allowed to meet the minimum fan balance quality grade of G6.3. We measure the fan’s maximum imbalance allowed on each side in grams based on the size of the fan wheel.

This dynamic industrial fan balancing process is meticulous, measuring amplitude and phase. This determines adjustments needed which are made through welding (adding) and/or grinding (removing) weight. Getting this step right makes the next step much easier, but no less important.

Stage Two: Trim Balance

After dynamic balancing is complete, the fan wheel goes into the housing and the entire fan is assembled. Now, it’s time to run the fan at full operating speed and perform the trim balance.

Trim balancing includes three phases: vertical, horizontal, and axial. We make sure that it is balanced within certain limits in those three phases before we consider it to be a balanced fan ready for shipping and installation. This involves nuanced tweaks: grinding a little weight off, welding a little weight on, or adding stiffness in your system to get the fan to the required balance levels. 

Final Check, Post Installation

Don’t forget to check final vibration levels after installation in the field! As your new fan is in transit to its destination, components can shift. Most shipping carriers are careful, but things like potholes, fast stops, or loading/unloading errors can cause damage you don’t always see. With this in mind, it is critical post installation to check for loose parts and perform a vibration test.

Hear it from an Application Engineer

Chet White, Senior Application Engineer / Sales & Marketing Manager, discusses the two stages of industrial fan balancing in this brief video.

To ask questions, get more details, or discuss your application, reach out and connect with one of our application engineers.

Related Content

Can’t get enough or need to know more? Several additional posts might interest you as you think about balance, vibration, and long fan life.

We welcome comments and questions via our LinkedIn Page, and you can always contact us for more details.