The Measurement of Very Low Frictional Torques in Rotating Equipment

Abstract

In the design of high precision, rotating equipment such as air bearings, gyroscopes, etc., it has become possible to reduce the frictional torques to “almost zero” values. The measurement and classification of the sources of these minute torques during rotation is exceedingly difficult, but very important for correct application and further design improvement. It is the purpose of this paper to present two techniques for the measurement and discrimination of the torques, and an example showing the accuracy of these techniques. Although these methods were designed specifically for the measurements of low torques, they work equally well for any magnitude and as such present a good evaluation technique. A comparison made with the values obtained by one of the better “direct” methods indicates that the direct method is inadequate.