P2.5 - High-Precision Online Sensor Condition Monitoring of Industrial Oils in Service for the Early Detection of Contami¬nation and Chemical Aging

SENSOR+TEST Conferences 2011
2011-06-07 - 2011-06-09
Proceedings SENSOR 2011
P2 - Calibration, Maintenance, Monitoring
M. Mauntz - cmc Instruments GmbH, Eschborn, U. Kuipers - University of Applied Science Südwestfalen, Hagen, J. Gegner - Universität Siegen (Germany)
702 - 707


A new online diagnostics system for the continuous condition monitoring of, e.g., lubricating and insulating oils in industrial gearboxes or transformators is presented. Characteristic features of emerging component damage, such as wear or chemical aging, are identified in an early stage. The OilQSens® Sensor effectively controls the proper operation conditions of bearings or gears.

The online diagnostics system measures components of the specific complex impedance of oils. For instance, metal abrasion due to wear debris, broken oil molecules, forming acids or oil soap result in an increase of the electric conductivity, which directly correlates with the degree of pollution in the oil. The dielectrical properties of the oils are particularly determined by the water content that becomes accessible via an additional accurate measurement of the dielectric constant, in the simplest case for products not enriched with additives. For additivated oils, statements on the degradation of additives can also be derived from changes in the dielectric constant.

For an efficient machine utilization and targeted damage prevention, the new OilQSens® online condition monitoring system allows for timely preventative maintenance on demand rather than in rigid inspection intervals. The determination of impurities or reduction in the quality of the oil and the quasi continuous evaluation of wear and chemical aging follow the holistic approach of a real-time monitoring of a change in the condition of the oil-machine system.

The measuring signals are transmitted to a webbased condition monitoring system via LAN, WLAN or serial interfaces of the sensor system. Monitoring of the damage mechanisms during proper operation below the tolerance limits of the components enables specific preventive maintenance independent of rigid inspection intervals. The function of the online condition monitoring system is successfully tested on a bearing and gear test rig applying various stress cycles.