Project Overview: A compressor motor was experiencing excessive shaft voltages, with over 40V passing through the bearings, posing a risk of bearing damage due to Electrical Discharge Machining (EDM). Our team was called to the site to diagnose the issue and perform corrective measures, including bearing replacement and the installation of an AEGIS Self Grounding Ring (SGR).
Challenges: During the initial inspection and testing of the compressor motor, we detected significant shaft voltages exceeding 40V, which can lead to electrical arcing and damage to the motor’s bearings. High shaft voltages create conditions for Electrical Discharge Machining (EDM), a process where electrical sparks erode the metal in the bearings.
To mitigate further damage, we recommended the following interventions: Fitting an insulated bearing to the Non-Drive End (NDE) and Installing an AEGIS Self-Grounding Ring (SGR) to the Drive End (DE) to safely discharge stray voltages.
Solution: Our team mobilised to the site, using the Lift & Shift team to dismantle the motor and replace its bearings. The old bearings were removed, and a new insulated bearing was installed at the Non-Drive End (NDE) to prevent electrical arcing. An AEGIS Self-Grounding Ring (SGR) was fitted to the Drive End (DE) with an earth braid to ground stray shaft currents. After reassembly, the motor was tested, showing a drop in shaft voltage from over 40V to under 2V, ensuring safe operation.
Outcome: The onsite works were completed successfully, addressing the excessive shaft voltage issue. The use of insulated bearings and the AEGIS SGR effectively mitigated the electrical discharge risk, protecting the motor’s bearings from further EDM damage. Upon inspection of the removed bearings, visible signs of EDM were confirmed, validating the need for the intervention.
