Eddy current sensors in tribology testers

Eddy current sensors from Micro-Epsilon are once again being used in a new high-performance test system at the Institute for Tribology at the Clausthal Technical University. The new tester, which is currently under construction, will be used to examine the tribological, flow mechanics and rotor dynamic processes of highly loaded sliding bearings at maximum circumferential speeds of the shaft. Based on previous positive experiences with Micro-Epsilon eddy current sensors used on existing testers for examining hydrodynamic radial plain bearings or plain bearings with particularly high loads, eddyNCDT series sensors will also be used in the new tester. In doing so, the shaft reaches circumferential speeds of up to 200m/s; conventional test systems achieve a maximum of 120m/s.

The position of the test bearing housing and the relative movement between the rotor and the test bearing is detected in the tester using eddy current displacement sensors. The bearing gap of the plain bearing between bearing surface and rotor is also measured using eddy current sensors. Or this, 22 sensor channels will be integrated in the test structure. Miniature eddyNCDT sensors with 0.5mm measuring range are used due to their high cut-off frequency and high resolution. Another key criterion is the sensor’s small installation footprint. Therefore, measuring points for very tight installation requirements are possible without requiring any disruptive modifications to the test design. High environmental compatibility is also a key reason for selecting eddy current sensors: oil or water in the measuring gap, high temperatures or strong electromagnetic interference fields.