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Updated: Oct 7, 2025

Design, Instrumentation and Usage Protocols for Distributed In Situ Thermal Hot Spots Monitoring in Electric Coils using FBG Sensor Multiplexing
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Electrical Discharges in Oil-Lubricated Rolling Contacts and Their Detection Using Electrostatic Sensing Technique.

Kamran Esmaeili1, Ling Wang1, Terry J Harvey1

  • 1nCATS, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton SO17 1BJ, UK.

Sensors (Basel, Switzerland)
|January 11, 2022
PubMed
Summary

Electrical discharges in rolling element bearings, even at low currents, damage components and reduce life. New sensors effectively detect and quantify these discharges, aiding WEC formation studies.

Keywords:
WEC formationdetection and diagnosiselectrical dischargeselectrostatic sensorquantification algorithmvoltage measurement technique

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Area of Science:

  • Tribology
  • Electrical Engineering
  • Materials Science

Background:

  • Parasitic and stray currents in rolling element bearings cause damage.
  • High current densities lead to fluting/corrugation; low current densities (<1 mA/mm²) cause white etching cracks (WECs).
  • Limited understanding of low current density discharges due to lack of in-situ quantification techniques.

Purpose of the Study:

  • Investigate electrical discharges in rolling contacts at low current densities.
  • Evaluate the effectiveness of voltage and electrostatic sensors for in-situ discharge quantification.
  • Understand the influence of mechanical and electrical conditions on discharge behavior.

Main Methods:

  • Utilized a TE74 twin-roller machine with an oil-lubricated steel-steel contact.
  • Employed voltage measurement and electrostatic sensors for in-situ discharge detection and quantification.
  • Varied electrical and mechanical conditions (temperature, load, speed, slip).

Main Results:

  • Discharge events are significantly influenced by temperature, load, and speed.
  • Sensor effectiveness demonstrated for detecting, characterizing, and quantifying discharges.
  • Established a link between discharge behavior and lubricant film thickness/contact area.

Conclusions:

  • Developed and validated a sensor-based method for studying low current density electrical discharges.
  • The sensors provide a robust tool for investigating the impact of discharges on WEC formation.
  • Findings advance the understanding of bearing degradation mechanisms under electrical stress.