Bently Nevada 330702-00-26-10-11-05 Proximity Probe – 3300 XL Series

Bently Nevada 330702-00-26-10-11-05 — Eddy-Current Proximity Probe for Critical Rotating Machinery Protection

The Bently Nevada 330702-00-26-10-11-05 is a field-proven, non-contact eddy-current proximity probe engineered for continuous shaft vibration and axial position measurement in high-stakes rotating machinery applications. As a core transducer within the 3300 XL Proximity Transducer System, this probe operates on the principle of electromagnetic induction: a high-frequency oscillating magnetic field generated at the probe tip induces eddy currents in the conductive target surface (typically a shaft journal), and the resulting impedance change is converted by the paired proximitor into a calibrated DC voltage output proportional to the gap distance. This mechanism delivers sub-micron resolution without mechanical contact, eliminating wear-induced drift that plagues conventional displacement sensors in high-cycle environments.

The part number structure encodes precise physical configuration: 330702 identifies the probe body family; 00 denotes the standard armored cable jacket; 26 specifies a 26-inch (660 mm) integral cable length; 10 indicates the 10-32 UNF thread form; 11 defines the 11 mm active tip diameter; and 05 designates the standard coaxial connector termination. Each parameter directly governs system compatibility — mismatching any single field against the extension cable or proximitor will shift the system scale factor and introduce calibration error. Engineers specifying replacement units must verify all six fields against the installed system BOM before procurement.

In a typical API 670-compliant machinery protection loop, this probe is installed radially at the bearing journal, paired with a Bently Nevada 330730-series extension cable of matched length, and terminated at a 3300 XL 8 mm Proximitor (330180 series). The proximitor supplies the probe with a regulated 24 VDC excitation and conditions the raw impedance signal into a ±24 VDC output with a nominal scale factor of 200 mV/mil (7.87 V/mm). The linear measurement range spans 0 to 90 mil (0 to 2.29 mm) gap, with a recommended operating gap of 50 mil (1.27 mm) at mid-scale. Output is fed directly into a Bently Nevada 3500 Series monitor rack for alarm and trip processing, or into a DCS analog input card for trend logging.

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Technical Parameters

Hardware Logical Analysis

The 330702-00-26-10-11-05 probe body is machined from 316 stainless steel, selected for its corrosion resistance in oil-mist and process-gas environments and its non-magnetic properties, which prevent interference with the probe’s own electromagnetic field. The 11 mm tip diameter governs the depth of the eddy-current field penetration into the target: a larger tip produces a broader, shallower field with improved sensitivity to surface irregularities, while the 11 mm form factor balances spatial resolution against installation envelope constraints typical of turbine bearing housings.

The integral 26-inch cable is a coaxial construction with a controlled characteristic impedance matched to the 3300 XL system’s operating frequency (nominally 1.0 MHz). The armored jacket (field code 00) provides mechanical protection against abrasion and crush loads in confined bearing pedestals without adding ferromagnetic shielding that would alter the cable’s RF transmission characteristics. The total system cable length — integral probe cable plus extension cable — must equal the proximitor’s calibrated length (typically 5 m, 9 m, or 15 m total); deviating from this sum shifts the LC resonant frequency of the probe-cable network and displaces the scale factor by up to ±5%, which exceeds API 670 accuracy tolerances.

EMC performance is achieved through the coaxial cable geometry itself: the outer shield carries the return current path and attenuates external RF interference before it reaches the center conductor. In installations near variable-frequency drives or high-current bus bars, additional ferrite chokes on the extension cable can suppress common-mode noise above 100 kHz without affecting the 1 MHz probe signal. The 10-32 UNF thread form provides a fine-pitch mechanical lock that resists vibration-induced loosening under continuous dynamic loading — a critical detail in applications where probe gap drift of even 2 mil can trigger nuisance alarms in tightly configured protection setpoints.

System Integration Benefits

• Deterministic gap-to-voltage linearity: The 200 mV/mil scale factor is stable across the full –35 °C to +177 °C operating range when the matched proximitor is used, enabling consistent alarm setpoint calibration without temperature compensation offsets in the monitor.
• Zero mechanical wear: Non-contact measurement eliminates the tribological degradation that affects LVDT and contact-type displacement sensors, sustaining measurement accuracy over multi-year continuous operation between planned outages.
• API 670 compliance out of the box: The probe-cable-proximitor system meets the transducer performance requirements of API 670 Fifth Edition, simplifying documentation for machinery protection system audits in oil & gas and petrochemical facilities.
• Plug-compatible replacement: The 330702-00-26-10-11-05 is a direct form-fit-function replacement for any installed unit sharing the same six-field part number, requiring no re-ranging of the monitor channel or adjustment of the proximitor gap voltage at installation.
• Diagnostic transparency via gap voltage: The DC output voltage at the proximitor terminal provides a real-time, continuous indication of probe-to-shaft gap. Technicians can verify probe seating and target surface condition with a standard voltmeter without interrupting machine operation.
• Broad monitor compatibility: Output signal is compatible with Bently Nevada 3500 Series, 3300 Series, and third-party monitors accepting ±24 VDC eddy-current transducer inputs, providing flexibility in mixed-fleet protection architectures.
• Hazardous area adaptability: When paired with the Bently Nevada 3300 XL Zener Barrier, the system meets intrinsic safety requirements for Zone 1 / Division 1 classified areas, covering LNG, refinery, and offshore platform installations.
• Reduced commissioning time: Factory-calibrated scale factor and documented gap-voltage tables eliminate field calibration iterations, allowing maintenance teams to restore machinery protection coverage within a single shift window during planned outages.

Quality Assurance & Global Logistics

Every Bently Nevada 330702-00-26-10-11-05 unit dispatched from our Xiamen, China facility undergoes a structured pre-shipment verification protocol. Physical inspection covers label integrity, connector pin condition, cable sheath continuity, and tip surface finish. Serial numbers and date codes are cross-referenced against procurement documentation to confirm supply chain traceability. Units are packed in anti-static, moisture-barrier pouches sealed within rigid foam-lined cartons, maintaining probe tip and connector protection through international air freight handling.

Shipments are dispatched via DHL Express, FedEx International Priority, or UPS Worldwide, with typical transit times of 3–5 business days to Europe, North America, and Southeast Asia. Full export documentation — commercial invoice, packing list, and certificate of origin — is provided as standard. HTS classification and ECCN data are available on request for import compliance purposes. Bulk orders of 5 or more units qualify for consolidated shipment pricing and dedicated account coordination. All units carry a 12-month warranty against manufacturing defects from the date of dispatch.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
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