Bently Nevada 330876-02-10-01-00 Proximity Probe – 3300 XL Series

Bently Nevada 330876-02-10-01-00: 50 mm Eddy-Current Proximity Probe for Continuous Shaft Monitoring in the 3300 XL Transducer System

The Bently Nevada 330876-02-10-01-00 is a 50 mm (2-inch) tip-diameter eddy-current proximity probe manufactured for the 3300 XL Proximity Transducer System. Its primary function within a machinery protection architecture is the continuous, non-contact measurement of radial shaft vibration, axial thrust position, and differential expansion on rotating equipment — turbines, centrifugal compressors, boiler feed pumps, and large motor-driven trains operating under API 670 protection requirements.

Unlike smaller-diameter probes (8 mm or 25 mm), the 50 mm tip geometry produces a substantially larger electromagnetic field cone, extending the linear measurement range to 0–2.54 mm (0–100 mil) and improving signal-to-noise performance on large-diameter shafts where surface finish variation and runout can otherwise introduce measurement uncertainty. The probe integrates directly into the three-component Bently Nevada transducer chain — probe, extension cable, and proximitor — without requiring recalibration when replacing a like-for-like unit.

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Technical Parameters

Hardware Logical Analysis

The 330876-02-10-01-00 operates on the principle of high-frequency eddy-current induction. An internal oscillator within the paired 3300 XL proximitor drives a resonant LC circuit whose inductive element is the probe coil wound at the 50 mm tip. When a conductive target (shaft surface) enters the electromagnetic field, eddy currents are induced in the target material, loading the LC circuit and reducing its Q-factor. The proximitor’s demodulator stage converts this impedance shift into a DC voltage linearly proportional to the probe-to-target gap — the fundamental measurement signal.

EMC Design: The armored coaxial cable construction provides continuous RF shielding from probe tip to proximitor input, suppressing common-mode interference from adjacent VFDs, high-current bus bars, and switching power supplies — all typical in turbomachinery control rooms. The hermetically sealed 316 SS housing prevents moisture ingress and eliminates the capacitive coupling paths that degrade measurement accuracy in steam-laden or oil-mist environments.

50 mm Tip Geometry Advantage: The larger coil diameter increases the effective sensing area, which reduces the sensitivity of the output to localized shaft surface anomalies (scratches, pitting, plating variations). This is particularly relevant on older machinery where shaft surface condition may not meet new-equipment standards. The wider field cone also provides a more uniform response across the full 0–100 mil linear range, maintaining scale factor accuracy at both near-gap and far-gap extremes.

Target Material Compensation: The standard calibration is performed against AISI 4140 steel. For shafts manufactured from non-standard alloys — Inconel 718, titanium 6Al-4V, or aluminum — the electrical conductivity and magnetic permeability differences alter the eddy-current loading characteristic. Bently Nevada publishes material correction curves; applying the appropriate factor to the scale factor restores measurement accuracy without hardware modification.

Thermal Stability: The probe’s internal coil assembly is wound with temperature-compensated wire and potted in a thermally stable compound. Over the full –35 °C to +177 °C operating range, scale factor drift is held within the system specification, ensuring that temperature excursions during startup, load changes, or ambient variation do not introduce false alarm or trip conditions.

System Integration Benefits

• Direct 3300 XL / 3500 Series compatibility: The probe interfaces plug-and-play with Bently Nevada 3300 XL proximitors and 3500 Series monitoring rack I/O modules. No firmware changes or recalibration are required for like-for-like replacement, minimizing planned maintenance downtime windows.
• API 670 compliance: The transducer system meets the measurement chain requirements of API Standard 670 (Machinery Protection Systems), making it directly applicable to new installations and retrofit projects on API-governed equipment without additional engineering justification.
• Deterministic DC output: The –2 VDC to –18 VDC analog output is a low-impedance, noise-immune signal that feeds directly into DCS or PLC analog input cards (4–20 mA conversion via signal conditioner, or direct voltage input on compatible modules) with deterministic latency — no protocol overhead, no network jitter.
• Flat frequency response to 10 kHz: Sub-synchronous instabilities (oil whirl at 0.4–0.5×), synchronous 1× unbalance, and high-frequency structural resonances up to 10,000 Hz are all captured within the probe’s bandwidth without amplitude attenuation, supporting both protection and diagnostic trending functions from a single transducer.
• Non-contact, zero-wear operation: The absence of mechanical contact between probe and shaft eliminates wear-related drift over time. The probe maintains its calibration state across continuous 24/7 duty cycles without scheduled replacement intervals driven by mechanical fatigue.
• Diagnostic transparency: The DC gap voltage is directly readable at the proximitor output connector, enabling field technicians to verify probe-to-shaft gap without removing the probe from the machine — a critical capability during commissioning and post-maintenance verification.
• Redundancy architecture support: The probe’s compact form factor and standard coaxial interface support dual-redundant transducer installations (two probes at 90° separation per API 670 radial vibration requirement) without mechanical interference, enabling 2-of-2 or 2-of-3 voting logic in the protection system.
• Long cable system reach: When paired with Bently Nevada 330130-series extension cables, the total probe-to-proximitor cable system can extend to 5 m, 9 m, or longer standard lengths, accommodating installations where the proximitor must be located outside the hazardous area or in a remote junction box.

Quality Assurance & Global Logistics

Every Bently Nevada 330876-02-10-01-00 unit supplied by siemensplc.com is sourced through verified distribution channels with full part number traceability. Pre-shipment inspection covers visual examination of the probe tip and housing, connector integrity and coaxial continuity verification, and confirmation of original manufacturer labeling against the Bently Nevada part number structure. A Certificate of Conformance (CoC) is available with every shipment upon request.

Our anti-counterfeit incoming inspection protocol is aligned with AS6081 practices for industrial automation components. Each unit is cross-referenced against known-genuine samples for dimensional, marking, and connector characteristics before dispatch.

Logistics are managed from our warehouse in Xiamen, China. Standard international 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, Southeast Asia, and the Middle East. Express next-flight-out options are available for critical plant shutdowns. All shipments include commercial invoice, packing list, and CoC documentation to support customs clearance in regulated markets. Export compliance is verified against applicable trade control regulations prior to dispatch.

Contact Information

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