The Error Sources and Uncertainty Assessment for Single -Plane Fan Dynamic Balance System

摘要

The dynamic balance system is a basic measurement instrument to measure the imbalance value generated by a small fan or rotor. The purpose is to provide the standardization of measurement instrument for products in a production line. Signals measured by that system include computer-controlled signal output, rotor speed detected by a laser and vibration signals measured by an accelerometer, which can determine the imbalance location of a rotor and balance level after the calculation as well as verify the rotor system of dynamic balance by the methods in ISO 1940-2. This study empirically assesses the uncertainty of dynamic balance system, which follows “Guide to the Expression of Uncertainty in Measurement (referred to as ISO GUM below)” to assess the performance of dynamic balance system as a standard of balance level for measurement instrument. After assessed, the best status of the balance level for system capability conforms to the balance level G 0.2 of ISO 1940. Using a plastic screw as known standard mass 30 mg adds the system to simulate the mass of imbalance standard. After the system uncertainty with and without mass is assessed, the mass difference is very small and the angle difference is about 10 %. The system is assessed at different rpm without mass. The results show the uncertainty of fan dynamic balancing machine is higher at 10000 rpm, which can achieve the mass error < 1 mg, compensation degree error < 2o and minimum measured balance is 0.2 g mm. The uncertainties at different mass and rpm can be assessed in the future to provide each kind of on-line fan manufacture.