Bently Nevada 330801-16-04-075-00-02 Proximity Transducer Assembly – PROXPAC XL

Bently Nevada 330801-16-04-075-00-02 PROXPAC XL: Eddy-Current Proximity Measurement for Critical Rotating Machinery

The 330801-16-04-075-00-02 is a factory-assembled, pre-calibrated eddy-current proximity transducer system manufactured by Bently Nevada (Baker Hughes) for deployment within the System 3300 and System 3500 machinery protection platforms. Unlike field-assembled probe-cable-proximitor configurations, this PROXPAC XL unit ships as a matched, impedance-verified assembly — eliminating the single most common source of measurement error in rotating machinery monitoring: mismatched component calibration. The assembly integrates a 16 mm diameter probe, a 4-meter extension cable, and an integral proximitor module, all factory-characterized to a unified scale factor of 7.87 V/mm (200 mV/mil) across the full operating gap range.

In turbomachinery protection architecture, shaft radial displacement is a primary trip parameter. The 330801-16-04-075-00-02 feeds a continuous DC-coupled voltage signal — proportional to the instantaneous air gap between probe face and target shaft — directly into Bently Nevada 3300 or 3500 series monitor input cards. The monitor rack then applies alarm and danger setpoints per API 670 logic. Because the PROXPAC XL assembly is pre-characterized, the scale factor deviation across the operating temperature range is held within ±1%, a tolerance that field-assembled systems rarely achieve without dedicated calibration equipment.

This part number is specified by OEM turbine manufacturers, EPC contractors, and plant reliability engineers across petrochemical, LNG, power generation, and offshore platform applications. It is a direct-fit replacement for existing 330801 series installations and is interchangeable with System 3300 radial vibration and axial position monitor modules without firmware or configuration changes.

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

Technical Parameters

Hardware Logical Analysis

The 330801-16-04-075-00-02 operates on the principle of high-frequency eddy-current induction. The probe coil, driven by the proximitor oscillator at approximately 1 MHz, generates an electromagnetic field that penetrates the conductive target shaft surface. As the air gap changes, the eddy-current loading on the coil alters its impedance — specifically its effective inductance and Q-factor. The proximitor demodulates this impedance variation into a linear DC voltage output.

Several hardware design decisions distinguish the PROXPAC XL from generic eddy-current assemblies:

Impedance-matched cable architecture: The 4-meter extension cable is not a generic coaxial run. Its characteristic impedance is factory-matched to the probe coil at the operating frequency. A mismatch of even a few ohms at 1 MHz introduces a measurable shift in the effective scale factor — a failure mode that is invisible during static bench checks but manifests as a calibration offset under operating conditions. The PROXPAC XL eliminates this by characterizing the probe-cable-proximitor system as a single electrical network.

EMC shielding topology: The extension cable uses a double-braid shield construction with drain wire, providing greater than 60 dB of common-mode rejection against conducted and radiated interference. In turbine environments where variable-frequency drives, high-current bus bars, and ignition systems coexist within meters of the measurement chain, this shielding margin is not a specification luxury — it is a functional requirement for measurement integrity.

Thermal compensation in the proximitor: The proximitor circuit incorporates passive thermal compensation networks that counteract the temperature coefficient of the probe coil inductance. Without compensation, a probe operating at 150°C would exhibit a scale factor drift of approximately 3–5% relative to its 25°C calibration value — sufficient to cause nuisance alarms or, more critically, to mask a genuine shaft displacement event. The PROXPAC XL holds scale factor deviation within ±1% across the full –35°C to +177°C probe range.

Solid-state construction: No mechanical contacts, no moving parts, no wear surfaces. The MTBF for the 330801 series in continuous service exceeds 100,000 hours under standard API 670 installation conditions. This is a direct consequence of the all-solid-state signal chain from probe coil to proximitor output terminal.

System Integration Benefits

• Zero-configuration rack compatibility: The 330801-16-04-075-00-02 connects directly to Bently Nevada 3300 and 3500 series radial vibration and axial position monitor input cards. No jumper changes, no firmware updates, no scale factor re-entry — the monitor reads the standard 7.87 V/mm output natively.
• Elimination of field calibration risk: Factory pre-calibration removes the dependency on field calibration equipment and technician skill. The assembly arrives characterized; the installer verifies gap voltage at the nominal operating gap and commissions. This reduces installation time by 40–60% compared to field-assembled systems.
• API 670 compliance out of the box: The assembly meets the measurement chain requirements of API Standard 670 (5th Edition) for radial shaft vibration and axial position monitoring. No additional documentation or characterization is required for API 670 compliance audits.
• Deterministic frequency response: The flat frequency response from DC to 10,000 Hz ensures that the monitor rack receives an undistorted representation of shaft motion across the full spectrum of interest — from slow-roll runout at 1× to high-frequency blade-pass events at 10× and beyond.
• Diagnostic transparency: The DC-coupled output allows the monitor to distinguish between static gap (DC component) and dynamic vibration (AC component) simultaneously. This dual-channel information enables the monitor to detect both shaft centerline migration (a bearing wear indicator) and dynamic vibration amplitude within a single measurement channel.
• Reduced spare parts complexity: A single PROXPAC XL part number replaces three separate line items (probe, cable, proximitor) in the plant spare parts inventory. This simplifies procurement, reduces storage requirements, and eliminates the risk of stocking mismatched component combinations.
• Wide environmental tolerance: The probe’s rated operating temperature of –35°C to +177°C covers the full range of turbine hot-section installations without derating. The proximitor’s –35°C to +85°C range accommodates junction box installations in both arctic and tropical ambient conditions.
• Intrinsically safe options: The 330801 series is available in FM and CSA intrinsically safe configurations for Zone 1 / Division 1 hazardous area installations. The -02 suffix in this part number designates the standard (non-IS) configuration; IS variants are available upon request.

Quality Assurance & Global Logistics

Every 330801-16-04-075-00-02 unit stocked at siemensplc.com is sourced through verified supply channels and subjected to incoming inspection prior to listing. Inspection covers physical integrity of the probe body and connector, cable continuity and shield resistance, connector pin condition, and original Bently Nevada / Baker Hughes labeling and part number verification. Units that do not pass inspection are not listed for sale.

All shipments originate from our warehouse in Xiamen, China — a major international logistics hub with direct access to DHL Express, FedEx International Priority, UPS Worldwide Express, and SF International services. Standard export documentation (commercial invoice, packing list, certificate of origin) is prepared for every shipment. For plant and EPC applications requiring traceability, a Certificate of Conformance is available upon request at no additional charge.

Packaging follows ESD-safe and shock-protective standards: anti-static inner wrap, foam-cushioned outer carton, and moisture-barrier sealing for ocean freight options. Transit time to major industrial hubs — Rotterdam, Houston, Singapore, Dubai — is typically 3–5 business days via express courier. A 12-month warranty covers all units against manufacturing defects and functional failure under normal operating conditions.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
© 2026 siemensplc.com. All rights reserved.