Bently Nevada 330104-00-03-50-02-05 Proximity Transducer System – 3300 XL Series

Bently Nevada 330104-00-03-50-02-05: 8 mm Eddy-Current Proximity Transducer System for Critical Machinery Protection

The 330104-00-03-50-02-05 is a complete, factory-matched 8 mm eddy-current proximity transducer system within Bently Nevada’s 3300 XL Series platform. It comprises three interdependent subsystems — the 8 mm probe body, a matched-impedance extension cable, and the Proximitor® sensor — delivered as a calibrated assembly. This configuration is specified under API 670 (5th Edition) for non-contact measurement of radial shaft vibration displacement and axial position on critical rotating machinery including steam turbines, centrifugal compressors, boiler feed pumps, and high-speed gearboxes.

In a machinery protection loop, the transducer system occupies the first and most consequential position in the signal chain. The probe tip generates a high-frequency oscillating electromagnetic field (typically 1.0 MHz carrier frequency for 8 mm geometry). When a conductive target — shaft or thrust collar — enters the field, eddy currents are induced on the target surface, loading the oscillator circuit and producing a proportional change in output voltage. The Proximitor® demodulates this signal and outputs a DC voltage with a nominal sensitivity of 7.87 V/mm (200 mV/mil), linear across a calibrated gap range of approximately 0.25 mm to 2.54 mm. This analog output feeds directly into 3300 XL or 3500 Series monitor input cards without signal conditioning.

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Technical Parameters

Hardware Logical Analysis

The 8 mm probe geometry of the 330104-00-03-50-02-05 is not arbitrary. Probe diameter directly governs the depth of the eddy-current field penetration and the effective measurement range. An 8 mm probe produces a field depth of approximately 1× the probe diameter, yielding a usable linear range of roughly 0.25–2.54 mm — sufficient for shaft displacement measurement on machines with journal bearing clearances in the 0.10–0.30 mm range, while maintaining adequate standoff margin.

The matched-system architecture is a deliberate EMC and calibration control mechanism. The extension cable is not a generic coaxial cable; its characteristic impedance is tuned to the Proximitor® oscillator circuit. Substituting a non-matched cable alters the resonant frequency of the LC tank circuit within the Proximitor®, shifting the output sensitivity curve and introducing non-linearity at the extremes of the gap range. Factory matching eliminates this variable entirely — the system is calibrated as a unit on a certified calibration fixture traceable to NIST standards.

The Proximitor® sensor employs a differential demodulation topology. The oscillator output is split into two paths: one referenced to the probe gap signal, one to a fixed internal reference. The differential output rejects common-mode noise — including power supply ripple and thermally induced drift — before the signal reaches the output stage. This architecture delivers a noise floor below 25 µm pk-pk in a 10 kHz bandwidth, which is critical for detecting sub-millimeter shaft displacement events that precede bearing failure by hours or days.

The probe body itself uses a hermetically sealed coil assembly encapsulated in a chemically resistant housing. The coil winding geometry is optimized for the 8 mm tip diameter to maximize field uniformity across the active face, reducing sensitivity to minor angular misalignment between probe axis and shaft surface — a practical tolerance of ±3° is maintained without measurable sensitivity degradation. The housing material is selected for resistance to hydrocarbon process fluids, H₂S environments, and steam condensate, consistent with API 670 environmental requirements for turbomachinery installations.

System Integration Benefits

• Direct 3300 XL Monitor Compatibility: The −18 VDC nominal output is natively accepted by all 3300 XL Series monitor input cards (radial vibration, axial position, differential expansion) without signal conditioning or impedance matching at the panel.
• 3500 Series Cross-Compatibility: The Proximitor® output signal is electrically compatible with Bently Nevada 3500 Series monitor input cards in standard configurations, enabling use in mixed-generation protection systems without additional interface hardware.
• System 1® Software Integration: The calibrated sensitivity constant (7.87 V/mm) is directly entered into System 1® condition monitoring software, enabling accurate engineering-unit display (µm pk-pk) without field recalibration.
• Deterministic Alarm Response: The analog output architecture ensures that alarm and danger setpoints in the monitor are evaluated against a continuous, uninterrupted signal — no sampling latency, no digital conversion delay — preserving the sub-millisecond trip response time required by API 670 Section 5.
• Diagnostic Transparency via OK Circuit: The Proximitor® includes an internal OK circuit that monitors oscillator health and cable continuity. A loss-of-signal condition drives the output to a defined fault state (typically −24 VDC), which the monitor interprets as a sensor fault rather than a valid vibration reading — preventing false trips and enabling immediate maintenance dispatch.
• Redundant Voting Architecture Support: In 2oo3 (two-out-of-three) voting configurations, the matched sensitivity of factory-calibrated systems ensures that all three transducer channels produce consistent output for a given shaft displacement, preventing single-channel drift from triggering spurious majority votes.
• Minimal Installation Footprint: The 8 mm probe body accommodates tight radial clearances in bearing housings where larger 11 mm or 25 mm probes cannot be physically installed, expanding the range of machinery that can be brought into API 670 compliance without housing modification.
• Long-Term Calibration Stability: The hermetically sealed coil assembly and matched cable eliminate the primary sources of long-term sensitivity drift (moisture ingress, cable impedance change), reducing the required recalibration interval and lowering lifecycle maintenance cost per measurement point.

Quality Assurance & Global Logistics

Every 330104-00-03-50-02-05 unit offered through siemensplc.com is sourced as genuine Bently Nevada (Baker Hughes) OEM hardware. Units are procured through verified supply channels with documented chain of custody. Prior to shipment, each assembly undergoes a structured inspection protocol: physical integrity check of probe body, connector, and cable jacket; label and part number authentication against Bently Nevada published documentation; and where test equipment is available, bench verification of Proximitor® output voltage at a known gap distance against the published sensitivity curve.

Packaging follows anti-static and shock-isolation standards appropriate for precision sensor assemblies. The probe coil assembly is particularly sensitive to mechanical shock during transit; foam-lined rigid packaging is used to maintain the probe tip geometry and prevent coil displacement. A certificate of conformance is available upon request for each shipment.

Logistics operations are based in Xiamen, China — a major export hub with direct access to international express carriers (DHL, FedEx, UPS) and sea freight consolidators. Standard express delivery to destinations in Southeast Asia, the Middle East, Europe, and the Americas is typically achieved within 3–7 business days from order confirmation. For time-critical plant shutdowns or emergency maintenance windows, same-day dispatch on confirmed orders is available subject to stock status. Export documentation including commercial invoice, packing list, and certificate of origin is prepared in compliance with destination country import requirements.

Contact Information

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