The influence of the sensor position on the quality of the vibration measurement of rotating machinery on flexible supports

Every machine has mechanical moving parts in recent generate internal stresses in its structure. These efforts are manifested by the vibration of the whole structure of the machine. For the collection of data necessary to analyze the origin of these efforts are often used vibration sensors, whose function is to transform mechanical energy into a proportionate and measurable electrical signal. In the present work, we limited our study to the search for the best position of the sensor and the measurement point of taking a significant vibration. For this, we considered nine measurements points regularly distributed over half the circumference (180°) of the driving motor of a motor-fan group mounted on flexible substrates, so measurement points that have a pitch equal to 22,5°. In this installation, we have identified three zones; A, B, and C there is seen that amortization is only provided and limited by zone B. The measurements made, have led us to confirm that the measurements points to this type group of motor-fan, will be performed on the horizontal plane and loins of the amortized zone B. In addition, we have taken for this analysis both measurement, one without unbalance and another with the presence of unbalance. In the end, the FFT calculation under Matlab software of the time signal data delevred by the sensor to an oscilloscope is used.