Bently Nevada 3300 Series Proximity Probe System

Technical Dossier

Product Details And Specifications

Bently Nevada 3300 Series Technical Notes

The Bently Nevada 3300 Series proximity probe system is one of the most widely deployed non-contact vibration and position measurement platforms in global heavy industry. Installed across petrochemical refineries, nuclear power stations, offshore platforms, LNG terminals, and rotating machinery facilities, the 3300 Series forms the sensing backbone of machinery protection systems (MPS) compliant with API 670. Its eddy-current operating principle enables continuous, non-contact measurement of shaft radial vibration, axial position, differential expansion, and eccentricity — without physical contact with the rotating element. The system's three-component architecture (probe, extension cable, proximitor/oscillator-demodulator) has remained the industry reference standard for over three decades, with installations documented in facilities operated by Shell, ExxonMobil, SABIC, Sinopec, and major nuclear operators across Europe and Asia. The 3300 Series is engineered for continuous operation in ambient temperatures from -35°C to +85°C, with probe tip ratings extending to 177°C in high-temperature variants, making it suitable for steam turbine bearing housings, compressor trains, and boiler feed pump applications.

The Evolution of 3300 Series Architecture

The 3300 Series was introduced by Bently Nevada (acquired by GE in 2002, subsequently integrated into Baker Hughes in 2017) as a successor to the earlier 7200 Series and 3000 Series probe systems. The original 3300 architecture standardized on a 5-meter armored coaxial cable assembly with a 19 mm diameter probe body, operating at a nominal gap voltage of -10.5 VDC at 1.27 mm (50 mil) gap. The proximitor module — designated the 3300 XL 8mm or 3300 5mm depending on probe diameter — converts the oscillator frequency shift caused by eddy-current coupling into a linear DC voltage output, typically -200 mV/mil (7.87 V/mm) scale factor.

Early 3300 deployments (pre-2000) used the standard temperature (ST) probe variants with Teflon-jacketed cables and brass probe bodies. Post-2000 revisions introduced the High Temperature (HT) and Extended Temperature (ET) variants with ceramic-tipped probes and stainless steel bodies rated to 177°C. The introduction of the 3300 XL sub-series brought improved EMI shielding, tighter scale factor tolerances (±1% vs. ±3% on legacy units), and compatibility with the System 1 condition monitoring software platform. The NSv (Non-Standard voltage) variants were developed for installations requiring -24 VDC supply rather than the standard -24 VDC regulated rail, addressing legacy DCS integration requirements in older refinery control architectures. As of 2024, the 3300 Series has entered the mature/end-of-active-production phase for several sub-variants, with Baker Hughes directing new installations toward the 3500 Series rack-based system and the Orbit 60 platform. However, the installed base of 3300 Series equipment in operating plants remains substantial, and replacement probe assemblies, extension cables, and proximitor modules continue to be required for planned maintenance, turnaround support, and emergency sparing.

3300 Series Full Catalog & Functionalities (SKU List)

The following SKUs represent the core and most frequently sourced components within the Bently Nevada 3300 Series proximity probe system. Each entry reflects a distinct functional specification within the system architecture.

330103-00-07-10-02-CN: 3300 XL 8mm proximity probe, 7-inch armored cable, standard temperature, metric thread, reverse mount, CE/ATEX marked.
330103-00-07-10-05-CN: 3300 XL 8mm probe, 7-inch cable, standard temp, metric thread, standard mount, CE/ATEX.
330103-00-07-10-CN: 3300 XL 8mm probe, 7-inch integral cable, standard temperature, metric thread configuration.
330103-00-12-10-02-CN: 3300 XL 8mm probe, 12-inch armored cable, standard temperature, metric thread, reverse mount.
330103-00-12-10-05-CN: 3300 XL 8mm probe, 12-inch cable, standard temp, metric thread, standard mount.
330104-00-07-10-02-CN: 3300 XL 8mm high-temperature probe, 7-inch cable, HT-rated to 177°C, metric thread, reverse mount.
330104-00-12-10-02-CN: 3300 XL 8mm HT probe, 12-inch cable, 177°C rating, metric thread, reverse mount.
330130-080-01-00: 3300 XL 8mm proximitor/oscillator-demodulator module, standard output, -24 VDC supply, DIN rail mount.
330130-080-01-05: 3300 XL 8mm proximitor module, extended output range, -24 VDC, panel mount configuration.
330180-X1-05: 3300 XL 5mm proximity probe, 5-inch integral cable, standard temperature, metric thread.
330180-X1-12: 3300 XL 5mm probe, 12-inch cable, standard temperature, metric thread, general-purpose mount.
330185-02-12: 3300 XL 5mm extension cable assembly, 12-inch, armored coaxial, standard temperature rating.
330185-02-24: 3300 XL 5mm extension cable, 24-inch, armored coaxial, standard temperature, field-replaceable connector.
330190-080-01-00: 3300 XL 5mm proximitor module, -24 VDC supply, standard scale factor output, DIN rail mount.
330191-00-24: 3300 XL 8mm extension cable, 24-inch, armored coaxial, standard temperature, field-replaceable BNC connector.
330191-00-36: 3300 XL 8mm extension cable, 36-inch, armored coaxial, standard temperature, field-replaceable connector.
330191-00-60: 3300 XL 8mm extension cable, 60-inch, armored coaxial, standard temperature, long-reach installation.
330500-00-05: 3300 NSv 8mm proximitor, non-standard voltage variant, -24 VDC input, legacy DCS integration output.

Sourcing Hard-to-Find & Obsolete 3300 Series Parts

For turnaround (TAR) and planned maintenance events, DriveKNMS provides advance reservation of 3300 Series probe assemblies, extension cables, and proximitor modules against confirmed plant schedules. Emergency sparing requests — including urgent RFQ handling for critical rotating machinery failures — are handled through our 24/7 logistics coordination. All 3300 Series units supplied by DriveKNMS are accompanied by full traceability documentation including source records, inspection reports, and functional test certificates. For plants operating under API 670 compliance requirements, DriveKNMS can provide documentation packages compatible with site QA/QC procedures.

Quality Control for the 3300 Series Range

The Bently Nevada 3300 Series presents specific quality verification challenges due to the interdependency of the three-component system (probe, extension cable, proximitor). A proximitor module that passes bench-level DC output testing may still exhibit scale factor drift when paired with a probe of non-matching gap sensitivity. DriveKNMS applies a system-level test protocol that replicates the installed operating condition rather than testing components in isolation.

Each 3300 Series probe assembly is tested for gap voltage linearity across the full measurement range (0 to 90 mil / 0 to 2.29 mm) using a calibrated target disk of the same material specification (AISI 4140 steel) as the API 670 reference standard. Scale factor verification is performed at three gap points (25 mil, 50 mil, 75 mil) with tolerance acceptance of ±1% for XL-series units and ±3% for legacy standard units. Extension cables are tested for coaxial impedance continuity, shield integrity, and connector contact resistance. Proximitor modules undergo supply current draw verification, output voltage accuracy at reference gap, and thermal stability testing at 25°C and 70°C. Units exhibiting scale factor deviation, oscillator frequency instability, or connector degradation are rejected and not returned to inventory. All test data is recorded and available for customer review upon request.