BALANCING A DUCTED FAN UNIT
There are several ways to perform EDF balancing. Regardless of which method is preferred, it is important to understand that EDF units are high powered machines that contain a lot of energy at high speeds. If any of the blades were to break off they become fast moving projectiles. Plan accordingly and stay safe.
The method that will be covered here is a method that takes in to consideration the balance of the motor and the fan as a single unit. In order to complete this type of balancing technique, trial and error method is used where the fan must spin up to operating speeds several times. Extra care must be taken and proper safety equipment must be worn.
– EDF STAND
– Scissors or hobby knife
– Marker to mark blades
– All electrical equipment to run the fan
– Safety Glasses
Step #1 – Prepare the fan blades by marking each blade one, two, three, four, until all blades have a number.
Step #2 – Mount the fan unit securely to an EDF mount on a work bench or table.
Step $3 – Wire up the fan for operation.
Step $4 – Run the fan up to speed and take note of the vibrational tone. Stop if there is excessive amounts of vibration.Record the amount of vibration on your own scale ranging from 1-10.
Step #5 – Rotate the fan unit 90 degrees on the motor shaft and repeat step 4 followed by step 5. Complete this so you have recordings for 0 degrees, 90 degrees, 180 degrees, and 270 degrees.
Step #6 – Choose the recording and angle from above that provided you with the least amount of vibration. Spin up the fan to confirm and take not of the vibrations. Continue on to step #7 if this does not apply to you or did not help.
Step #7 – Using scissors or a hobby knife to cut a small section of tape and place it on the inner hub of the fan blade marked number one
Step $8 – Spin up the fan unit to the same speeds as in step #6 and note of the difference. Stop if there is excessive amounts of vibration.
Step #9 – If vibration is reduced, cut off another strip of tape and add it to the inner hub of the fan. If vibration increased, remove the tape from the inner hub of blade one and place it on blade two.
Step #10 – Spin up the EDF unit once again. Note the vibrations. If you added tape and it improved, try adding more. If it did not, remove the tape and try the next blade number.
Step #11 – Continue trying these combinations until each blade has seen a piece of tape on the inner hub. If there is ever excessive vibration, stop the motor and continue the method of balancing.
Once Completed, the EDF unit should be in balance to provide smooth operation through out the RPM range. A smooth operating EDF unit will provide maximum life expectancy from the EDF unit, motor bearings and will also provide the best sound.