Motors & Pump Repairs in Sarasota, FL

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Fan Balancing Tips and Best Practices

Mike Jeffries | April 26, 2021

Balancing rotors is an established practice for keeping the motors running smoothly. The need to balance the fan is equally important, but often overlooked. Here are some of the best ways to balance the fan of your motor:

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3 Tips to Help Balance Your Fans

1. Balance Mandrel

In this method, the rotor is balanced first, and then used as a balance mandrel for balancing the fan. Since the rotor is heavier than the fan, you can use bar stock for creating the balancing mandrel.

For quicker and more efficient balancing, place the fan between the balancing shaft trunnions. Make sure the mandrel has been trim-balanced.

For easy reference, you can keep a color-coded chart with the step diameter of the correspondingly color-coded mandrel so you know which one to use while balancing fans of various sizes.


2. Precision Shafting

You can use precision shafting that has been ground to the required size to balance the fan. Minimize aerodynamic forces by rotating the fan backwards in the balancing stand.

You'll also need to monitor the current to make sure the drive motor does not get overloaded. If the fan is larger than average, you can wrap duct tape around its blades so air turbulence does not interfere with the rotation.

3. Hidden Factors

If a fan was built properly and running smoothly for some time before suddenly showing signs of not being well-balanced, the reason could be some internal problem other than simple unbalance.

You need to look for structural welds, defective bearings, or dirt that has lodged in the fan's crevices. Sometimes, moisture can also reach the fan due to rain or a nearby water source, and that leads to mud clinging to the blades of the fan.

Fans that have hollowed out blades can begin rusting from the inside. Loose fasteners or broken welding can also be responsible for a fan's uncharacteristic vibration.

In order to deal with these problems, the fan will need to be taken down and examined. Scrape away the rust or replace the blades if possible. Drill tiny holes at the tips of the blades to allow moisture to run off its body. Finally, give the fan a good cleaning, wipe off the water and let it dry off.

Following these fan balancing tips will help ensure that your fan does not produce unnecessary vibration the next time you use it, but instead produces smoother and more well-balanced rotation. If you have any other questions, feel free to contact us today to speak with an expert member of our team.

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Topics: motor, fan balancing

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