I'm trying to balance a rotatating drum on a prototype machine I'm building, and I have never done any dynamic balancing before. Most people use accelerometers for this but I don't have any so I'm using Piezo flex sensors with little overhung weights (https://www.sparkfun.com/products/9197). I have them held in my scope probes and just taped the probes onto the bearings on either side of the shaft. I'm running the motor (4 pole) on 50Hz so I expect to see a 25Hz waveform on both ends corresponding to to the imbalance. I do get the expected 25Hz on one end but on the other I get 50Hz.
Is this due to the small weight on the piezo sensor vibrating at a multiple of the vibration frequency seen at the bearing? Or is it possible that the bearing itself is actually vibrating at 50Hz? If it is the bearing then how would that be possible?
Is this due to the small weight on the piezo sensor vibrating at a multiple of the vibration frequency seen at the bearing? Or is it possible that the bearing itself is actually vibrating at 50Hz? If it is the bearing then how would that be possible?
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