A shaft-grounding ring offers a deliberate discharge path, but performance depends on shaft contact, contamination, mounting and the rest of the high-frequency grounding system. It cannot cure every circulating or common-mode bearing current.
A grounding ring is one part of the bearing-current strategy
Identify the current mechanism before selecting hardware. Circulating bearing current, shaft-grounding current and capacitive discharge do not share one universal remedy. Motor size, frame construction, cable and drive topology matter.
Mitigation map
| Item | Engineering purpose | Review action |
|---|---|---|
| Grounding ring | Shaft-to-frame path | Inspect contact and wear |
| Insulated bearing | Interrupt selected current loop | Confirm correct end and insulation |
| Cable shield | Drive-to-motor return | Use low-inductance termination |
| Common-mode filter | Reduce excitation | Coordinate with drive supplier |
Evidence required before approval
Measure shaft voltage with appropriate instrumentation and inspect both bearings. Maintenance must include ring wear, fibre condition and shaft-surface cleanliness. Approve a scheme only when the complete return path is documented.
Retain the equipment revision and test record. Name the reviewer. Keep open assumptions visible.
Commissioning decision
Never approve a copied setting. Confirm interface compatibility and operating limits. Exercise the intended response during a functional test.