Fixture for the High-Frequency Transfer Path Analysis for Relative Comparison of Fluids of an Electric Motor

Abstract

In a previous paper, it was determined that coolant fluids can have a significant influence on the acoustic emission of an electric motor. There is no appliance that can investigate and compare the transfer path analysis of isolated fluids. For this case, a new fixture is introduced and its suitability is evaluated. Furthermore, the appliance is used to measure and compare different media and their frequency response functions. The results indicate that the fixture and its repeatability are suitable to measure and compare fluids and media. A comparison of different media shows how the air medium has the lowest amplitudes for the transfer path analysis, in relation to incompressible fluids. Furthermore, differences in the transfer path analysis between both considered gearbox oils are marginal. While the utilization of air as a coolant medium is not always possible, due to thermal issues, the presented fixture can help find an acoustically suitable coolant medium for future applications in electric motors. Additionally, it is possible to investigate the influence of temperature and pressure conditions on the transfer path analysis of fluids.