Bently Nevada RAO00027 Accelerometer – Casing Vibration Sensor for Centrifugal Compressors

The Bently Nevada RAO00027 is an OEM-grade accelerometer for mounting on centrifugal compressor casings to capture reliable vibration data for protection and diagnostics. It’s designed for harsh rotating equipment environments and typically pairs with Bently Nevada 3500/3701 monitors, SCOUT portable systems, or ADRE data acquisition for condition monitoring. From my experience, this model family is favored when you need clean acceleration signals across a broad frequency range without fuss.

• Optimized for compressor casing vibration – Ideal for trending unbalance, misalignment, looseness, and flow-related issues such as surge or stall.

• Piezoelectric, IEPE-compatible output – Provides a stable mV/g signal that most industrial monitors and analyzers accept; typically works with 2–10 mA constant-current power.

• Broad usable bandwidth – Suits both low-frequency machinery trends and higher-frequency fault signatures (bearing, gearmesh, blade-pass), in many cases with a single sensor.

• Rugged, hermetically sealed design – Stainless-steel construction with high ingress protection for oily, hot, and vibration-intense areas around the compressor.

• Secure stud mounting – 1/4-28 UNF (typical) mounting provides solid mechanical coupling on machined pads near bearing housings.

• GE/Bently Nevada ecosystem compatibility – Integrates smoothly with 3500/3701 racks, SCOUT portable systems, and ADRE—reducing integration time.

• Field-proven in hazardous areas – Variants typically available with ATEX/IECEx certifications; many sites run these in Zone 1 environments. Always confirm the exact rating on your part number.

You’ll typically see the RAO00027 specified on:

• Centrifugal compressors in oil & gas (upstream, midstream, downstream)

• Petrochemical and chemical process compressors

• Refrigeration and air separation units

• Power generation auxiliaries and turbocompressors

Use cases range from routine casing vibration trending and balancing to early bearing fault detection. One thing I appreciate is how it captures blade-pass and flow instabilities when mounted correctly; you might notice cleaner spectrum peaks compared to lower-cost sensors.

• Reliability under heat and oil – The build holds up in compressor galleries where temperature and oil mist can cause cheaper sensors to drift.

• Drop-in ecosystem fit – Compatible with GE/Bently Nevada monitoring chains, reducing configuration time and minimizing field surprises.

• Lifecycle cost control – Stable calibration over years means fewer rework cycles and less troubleshooting during turnarounds.

• Support and documentation – In many cases, you’ll find reference mounting locations and recommended torque guidance in Bently Nevada packages, which keeps commissioning predictable.

Customer feedback from a midstream gas facility: “We bolted the RAO00027 onto the compressor discharge end, wired it to a 3500 rack, and the noise floor stayed low even near 120°C surfaces. Trend alarms were easy to set; no nuisance trips during startup ramps.”

• Mounting surface – Use a flat, clean, machined pad near the bearing housing. Avoid welded brackets where possible. Apply a thin film of grease for coupling if your site spec allows.

• Torque – Tighten to the manufacturer’s recommended value (often 2.8–8 N·m depending on stud size). Re-check torque after first thermal cycle.

• Cabling and shielding – Route away from high-voltage cabling and VFDs. Maintain proper shielding and grounding to keep the noise floor low.

• Junction boxes – For long runs, use sealed JB/termination boxes rated for the area classification. BNC or MIL connectors simplify maintenance.

• Maintenance – Visual inspection during outages, connector cleaning, and verification of cable integrity. Calibration check annually or per site QA. No firmware on the sensor, but keep monitor firmware current.

• Safety – De-energize IEPE power before disconnecting. Respect hazardous area work permits; use certified variants in classified zones.

• CE and RoHS compliance on most builds; documentation available on request

• ATEX/IECEx hazardous area certifications typically available for compressor service variants

• Manufacturing quality aligned with ISO 9001 systems

• Standard manufacturer warranty (commonly 1 year); extended service options may be available

• Bently Nevada 3500/3701 monitor channels for casing acceleration

• Portable analyzers such as SCOUT for route-based data collection

• Shielded IEPE sensor cables (MIL 2-pin or integral cable assemblies) and sealed junction boxes

• Stud mounting hardware (1/4-28 UNF), calibration adapters, and protective boots

Note: RAO00027 details can vary by suffix/build. If you share your compressor model and monitoring system, I can match the exact sensitivity, connector type, and certifications to your site standard before you commit.