All blades have been weighed and grouped according to weight. Their density can vary and therefore cause vibration even when all blades are of the same weight. The following methods can contribute to preventing most vibrations. Check the vibration before each procedure. Please not that a small amount of vibration is normal and does not pose a problem.
Most vibrations occur when one of the blades is not in alignment with the others. Aligning the blades is simply carried out with the aid of a flat ruler. Place the ruler vertically upwards against the ceiling and alongside the blade tip. Mark the distance between the blade side and ceiling. Turn the blades slowly by hand and carry out the same measurements with the other blades. If one of the blades is not correctly aligned, it can be remedied by lightly pressing their holders upwards or downwards in order to align them with the others.
Check that the mounting plate is firmly anchored to the ceiling.