Bently Nevada 330880-28-35-017-00-02 Proximity Transducer – PROXPAC XL

Bently Nevada 330880-28-35-017-00-02 PROXPAC XL Proximity Transducer Assembly — Shaft Vibration Measurement for Critical Rotating Machinery

The Bently Nevada 330880-28-35-017-00-02 is a factory-matched, complete proximity transducer assembly from the PROXPAC XL series, designed for continuous, non-contact measurement of radial shaft vibration and axial position in high-speed rotating machinery. Unlike field-assembled transducer chains, this assembly ships as a pre-calibrated, impedance-matched system — probe, extension cable, and connectors are factory-paired to a single sensitivity curve, eliminating the calibration drift that arises when components are mixed across production lots.

The model number encodes the physical configuration directly: 28-inch probe cable, 35-foot extension cable, and a 17 mm probe tip diameter. This dimensional specificity is not cosmetic — eddy-current proximity systems are highly sensitive to cable impedance, and any substitution of cable length outside the matched set will shift the output sensitivity away from the nominal 200 mV/mil (7.87 V/mm), introducing measurement error that no software compensation can fully correct. Specifying the exact part number is therefore a functional requirement, not a procurement formality.

siemensplc.com maintains verified stock of the 330880-28-35-017-00-02 sourced through traceable industrial supply channels. Each unit is cross-checked against OEM documentation before dispatch. Fast export from Xiamen, China with DHL Express and FedEx International Priority.

Real-time Stock & RFQ: [email protected] | WhatsApp: +86 18359268345

Technical Parameters

Hardware Logical Analysis

The 330880 series operates on the eddy-current principle: a high-frequency oscillator (typically 1.0 MHz carrier) drives the probe coil, generating an electromagnetic field that penetrates the target shaft surface. As the gap between probe tip and shaft changes, the induced eddy currents alter the coil’s impedance, which the oscillator-demodulator (Proximitor® sensor) converts to a DC voltage proportional to gap distance. The 200 mV/mil sensitivity figure is the slope of this voltage-gap transfer function across the linear operating range.

Impedance Matching and Cable System Integrity: The 330880-28-35-017-00-02 is a factory-matched assembly. The probe coil, probe cable (28 in), and extension cable (35 ft) are characterized together as a single electrical network. The Proximitor® sensor’s internal compensation is calibrated to the aggregate impedance of this specific cable length combination. Substituting a different cable length — even within the same 330880 family — shifts the resonant frequency of the LC network formed by the coil inductance and cable capacitance, displacing the linear range and altering sensitivity. Field engineers should never mix cable lengths from different assembly part numbers.

EMC Design and Shielding Architecture: The extension cable uses a double-shielded coaxial construction with a drain wire bonded to the connector shell at both ends. This topology provides common-mode rejection of conducted interference from variable-frequency drives, high-current bus bars, and RF sources common in turbomachinery enclosures. The shield is grounded at the Proximitor® sensor end only (single-point grounding), preventing ground loop currents from appearing as low-frequency noise on the measurement signal — a critical design choice in plants where multiple monitoring channels share a common rack ground.

Probe Tip Geometry and Target Material Considerations: The 17 mm tip diameter defines the effective sensing area and, consequently, the spatial resolution of the measurement. Larger tip diameters increase signal amplitude but reduce sensitivity to localized surface features. The 330880 series is calibrated against AISI 4140 steel targets; for shafts made of non-ferrous alloys (titanium, Inconel, stainless steel), a material correction factor must be applied at the monitor level. Failure to apply this correction introduces a systematic offset error proportional to the difference in electrical conductivity and magnetic permeability between the calibration target and the actual shaft material.

Thermal Stability: The probe’s rated operating range of −35 °C to +177 °C accommodates bearing housing temperatures in steam turbines and gas compressors without requiring active cooling. The extension cable’s lower upper limit (85 °C) reflects the thermal rating of the cable jacket material; routing the extension cable through high-temperature zones requires thermal isolation or conduit protection.

System Integration Benefits

• Zero-calibration replacement: Factory-matched assemblies install as direct drop-in replacements for existing 330880-28-35-017-00-02 units without requiring re-calibration of the Proximitor® sensor or monitor channel, reducing planned maintenance downtime to the physical swap time only.
• Deterministic signal latency: The eddy-current measurement chain introduces no sampling delay beyond the Proximitor® sensor’s analog bandwidth (typically >10 kHz), making the output suitable for real-time protection logic in the 3500 Series with sub-millisecond trip response.
• Diagnostic transparency via gap voltage: The DC gap voltage output provides a continuous, observable proxy for probe-to-shaft clearance. Trending this value over time reveals bearing wear, shaft thermal growth, and probe fouling — all without interrupting the measurement function.
• API 670 compliance path: When integrated with a 3300 XL or 3500 Series monitor configured to API 670 alarm and trip setpoints, this assembly forms part of a machinery protection system that satisfies the standard’s requirements for radial vibration and axial position channels.
• Multi-channel rack density: The 3500 Series accepts up to 16 transducer input channels per rack, and the 330880 assembly’s standard coaxial interface is directly compatible with all 3500/40M and 3500/42M I/O modules, requiring no signal conditioning adapters.
• DCS integration without signal conversion: The Proximitor® sensor’s 4–20 mA or ±10 V analog output connects directly to DCS analog input cards (Emerson DeltaV, Honeywell Experion, ABB 800xA) without intermediate signal converters, preserving measurement accuracy across the full transmission path.
• Predictive maintenance data quality: The 200 mV/mil sensitivity and >10 kHz bandwidth support spectral analysis up to at least the 10× running speed harmonic, providing sufficient frequency resolution for rotor dynamic fault signatures including unbalance, misalignment, oil whirl, and rub.
• Reduced spare parts complexity: Stocking the complete PROXPAC XL assembly as a single line item eliminates the need to maintain separate probe, cable, and connector inventories, reducing the risk of assembling a mismatched transducer chain during an emergency shutdown.

Quality Assurance & Global Logistics

Every Bently Nevada 330880-28-35-017-00-02 unit dispatched from siemensplc.com is sourced through verified industrial supply channels with full part-number and date-code traceability. Physical inspection covers label integrity, connector shell condition, cable sheathing continuity, and probe tip surface condition. Part numbers and revision markings are cross-referenced against Bently Nevada OEM documentation prior to listing.

Units are packed in anti-static, moisture-resistant packaging with individual tracking. Export documentation — commercial invoice, packing list, and certificate of origin — is prepared for every international shipment. HS code guidance is provided for customs clearance in regulated destinations.

Shipping from Xiamen, China: In-stock units typically ship within 1–3 business days via DHL Express, FedEx International Priority, or UPS Worldwide. Bulk orders (5+ units) qualify for volume pricing and sea freight options. All units carry a 12-month warranty from the date of shipment covering manufacturing defects and verified non-conformance to published specifications.

Contact Information

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