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Brush · Slip ring · Galvanic protection
Shaft Earthing Device
Shaft earthing brushes, slip rings, hull-to-shaft potential monitoring, anti-stray current protection.
Service available at all US ports — 24/7 worldwide. Our next available technician contacts you within 1 hour.
Symptom checklist
What we hear from the bridge.
- ›Shaft-to-hull voltage rising above 50 mV trend
- ›Worn brush, sparking visible on slip ring
- ›Mounting bracket vibration loose
- ›Cable to monitoring panel corroded
Likely root causes
Where the fault usually lives.
- ›Brush wear beyond minimum length
- ›Salt deposits on slip ring
- ›Aged copper braid
Equipment we bring
Calibrated test equipment, class-acceptable reports.
- Fluke 87V multimeter
- Calibrated mV shunt for shaft potential
- Vibration meter for bracket
Reports compatible with DNV · BV · ABS · Lloyd's · TL · RINA · ClassNK · IRS.
Often needed together
Parts most often requested with this service.
- shaft brushes
- slip rings
FAQ
Common questions for this system.
- Which shaft earthing brands and configurations do you service?
- Wartsila/Cathelco shaft brush units, MORGAN AM and electro-graphite brushes on bronze or silver slip rings, plus Cathelco hull ICCP reference cells where the shaft earthing reading is corrupted by the ICCP loop. We rebuild the brush gear, true the slip ring with fine emery, verify spring pressure, and bond down to the main earth bar with tinned copper strap to MIL/IACS recommended sub-1 milliohm shaft-to-hull resistance.
- How long does a shaft brush refurbishment take alongside?
- With the shaft stopped and locked out by the Chief Engineer, brush bar refurbishment, slip-ring polish, new brush set and shaft-to-hull millivolt verification run three to five hours. We use a Megger DLRO10X for the bond resistance and a Fluke 289 logging on millivolt range to capture the potential shift over a five-minute window. If the slip ring requires lathe truing in workshop, we arrange it through a local US machinist and return next day.
- Do you log the shaft potential reading for class records?
- Yes. The before/after shaft-to-hull millivolt reading, brush wear measurement and bond resistance are logged in the report format expected by DNV, BV, ABS, Lloyd's Register, ClassNK, RINA, TL and IRS. We reference the relevant class guidance (e.g. DNV-CG-0339 for shaft earthing) and attach a photo of the new brush set. The chief engineer's PMS card is updated with the next monthly potential check interval before we leave the engine room.
Have a vessel calling?
Three quick questions — port, when, contact. Our next available technician will contact you within 1 hour.