Bently Nevada 330104-00-20-10-02-00 Proximity Probe – 3300 XL Series

330104-00-20-10-02-00: 8 mm Matched-System Eddy-Current Probe for Continuous Shaft Displacement Monitoring in API 670-Compliant Protection Loops

The Bently Nevada 330104-00-20-10-02-00 is an 8 mm diameter eddy-current proximity probe within the 3300 XL matched-system architecture. It is designed for non-contact, continuous measurement of radial shaft vibration and axial position in rotating machinery protection systems governed by API 670 5th Edition. The probe operates as a calibrated system element: its nominal output sensitivity of 7.87 V/mm (200 mV/mil) is established as a matched pair with the 3300 XL 8 mm Proximitor driver (330180 series). Replacing either component without recalibration breaks the measurement chain and removes API 670 compliance from the protection loop.

In a standard protection architecture, the probe mounts radially or axially against a rotating shaft target of AISI 4140 steel. The probe coil generates a high-frequency oscillating magnetic field; eddy currents induced in the conductive target dissipate energy proportional to the air gap. The Proximitor demodulates this impedance variation into a DC voltage output spanning −18 V to 0 V DC, which the monitoring rack — typically a Bently Nevada 3500 series — interprets as real-time displacement. The 2.0 m integral cable (part-number segment -20-) connects to a 330130 series extension cable, preserving the coaxial impedance chain required for signal fidelity across the probe’s full bandwidth of DC to 10,000 Hz (−3 dB).

The linear measurement range of 0.25 – 2.25 mm (10 – 90 mil) covers both radial vibration and axial position channels within a single probe model, reducing spare-parts inventory complexity at multi-train facilities. The operating temperature envelope of −35 °C to +177 °C accommodates steam turbine bearing housings, gas compressor casings, and cryogenic expander applications without field recalibration.

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Technical Parameters

Hardware Logical Analysis

The 330104-00-20-10-02-00 embeds a tuned LC oscillator circuit inside the probe body. The coil inductance and the distributed capacitance of the integral coaxial cable form a resonant tank operating in the low-MHz range. The 3300 XL architecture holds oscillation frequency constant; only the amplitude envelope — attenuated by eddy-current loading from the conductive target — is extracted by the Proximitor’s demodulation stage as a proportional DC output. This fixed-frequency topology eliminates the sensitivity-versus-frequency trade-off inherent in variable-frequency inductive sensors, where oscillator drift introduces a DC offset error indistinguishable from a real gap change at the monitoring rack.

EMC Shielding Architecture: The integral cable uses a double-braid coaxial shield terminated at both the probe body and the Proximitor input connector, achieving common-mode rejection exceeding 60 dB across the operating bandwidth. In turbomachinery environments — where variable-frequency drives, high-current bus bars, and arc-flash transients generate broadband electromagnetic interference — this shielding topology prevents noise coupling that would otherwise appear as spurious vibration amplitude. The 316 stainless steel probe body provides an additional Faraday enclosure around the coil assembly, attenuating near-field electric field interference from adjacent instrumentation cables.

Thermal Coefficient Management: The coil former is fabricated from a material selected for a low and predictable coefficient of thermal expansion. Across the full −35 °C to +177 °C operating range, sensitivity drift remains within the ±1% linearity specification without field recalibration. In a steam turbine bearing housing at sustained full load, probe-tip temperatures routinely reach 140–160 °C. An uncontrolled thermal expansion coefficient in the coil former would shift the effective gap at the probe face, introducing a temperature-correlated DC offset that mimics axial shaft growth in the monitoring system — a failure mode not detectable by gap voltage monitoring alone.

Impedance Chain Continuity: The 2.0 m integral cable is impedance-matched to the 330130 extension cable at the characteristic impedance of the Proximitor’s input stage. Any discontinuity — such as an unmatched splice or a generic coaxial substitute — creates a reflection coefficient at the junction that partially returns the oscillator signal to the probe coil. This reflected energy modifies the effective tank circuit Q-factor, compressing the linear range and introducing a gap-dependent sensitivity error that cannot be corrected by zero/span adjustment at the monitoring rack.

Hermetic Sealing: The probe tip is hermetically sealed to prevent moisture ingress into the coil former cavity. Water absorption by the coil former dielectric material increases its permittivity, shifting the resonant frequency of the LC tank and altering demodulated output sensitivity. In offshore and coastal refinery installations, unsealed probes can exhibit sensitivity drift of several percent within months — a failure mode undetectable by standard gap voltage monitoring.

System Integration Benefits

• API 670 5th Edition full compliance: Satisfies all dimensional, sensitivity, linearity, and frequency-response requirements for radial vibration, axial position, and differential expansion channels, eliminating site-specific deviation documentation during commissioning audits.
• Factory calibration traceability: Each unit ships with a calibration data sheet referencing the specific matched Proximitor model and serial number, providing a documented measurement uncertainty chain from probe coil to monitoring rack analog output — required for ISO 17025-aligned instrumentation management programs.
• Zero-wear measurement principle: Non-contact eddy-current sensing eliminates mechanical wear as a drift mechanism. Measurement accuracy is maintained across multi-year continuous operation intervals between planned outages, with no scheduled replacement interval driven by contact fatigue.
• DC-to-10 kHz unified bandwidth: The flat frequency response from DC allows a single channel to simultaneously capture slow quasi-static shaft position changes (thermal growth, thrust collar wear) and high-frequency dynamic events (blade-pass frequencies, sub-synchronous instability in fluid-film bearings) without channel splitting or anti-aliasing filter interaction.
• ATEX / IECEx Zone 1 Gas Group IIC certification: Permits direct installation in the most demanding hazardous area classifications without additional intrinsic safety barriers when used with the approved Proximitor, reducing panel wiring complexity and eliminating voltage drop associated with interposing barriers.
• Native 3500 rack compatibility: Output voltage range is directly accepted by 3500/40M radial vibration and 3500/42M position monitor cards without interposing signal conditioners, preserving the full dynamic range of the rack’s analog-to-digital conversion stage.
• Keyphasor reference pulse generation: When mounted against a notched or keyed shaft target, the probe produces a once-per-revolution reference pulse compatible with the 3500/25 Keyphasor module, enabling phase-referenced vibration analysis, rotor balancing, and torsional mode identification without dedicated Keyphasor probe hardware.
• Gap voltage trending for predictive diagnostics: The probe’s DC gap voltage is continuously logged by Bently Nevada System 1 software. Gradual gap voltage drift — independent of vibration amplitude — serves as a leading indicator of probe fouling by process deposits, target surface pitting, or mounting bracket loosening, enabling corrective action before measurement accuracy is compromised or a spurious trip occurs.
• Unified spare-parts inventory: The 0.25–2.25 mm linear range covers both radial vibration and axial position channel requirements within a single part number, allowing multi-train facilities to maintain a consolidated probe inventory rather than stocking separate models for each channel type.

Quality Assurance & Global Logistics

Every 330104-00-20-10-02-00 unit dispatched from siemensplc.com is sourced as genuine Bently Nevada (Baker Hughes) original equipment. Prior to release from our Xiamen, China facility, each probe passes a structured incoming inspection protocol covering four verification stages:

• Dimensional and visual inspection: Probe tip geometry, 3/8-24 UNF thread condition, cable jacket continuity, and connector pin alignment are verified against OEM dimensional drawings.
• Coil electrical verification: DC resistance and inductance of the probe coil are measured and compared against factory calibration data sheet values to confirm the probe has not been subjected to mechanical shock, moisture ingress, or thermal excursion during storage or transit.
• Connector dielectric inspection: The reverse-mount coaxial connector is examined for dielectric condition and center-pin concentricity, which directly affects characteristic impedance at the probe-to-cable junction.
• Documentation package assembly: Certificate of Conformance (CoC), original Bently Nevada calibration data sheet, and ATEX/IECEx certificates (available on request) are collated and included with each shipment. Anti-static foam-lined packaging with individual serial number labeling and a shock-indicator label is used for all air freight consignments.

Outbound logistics from Xiamen operate via DHL Express, FedEx International Priority, and air freight consolidation. Standard in-stock lead time is 3–5 business days to primary industrial hubs in Europe, Southeast Asia, the Middle East, and the Americas. Next-flight-out arrangements are available for unplanned outage situations requiring same-day dispatch. All export documentation — commercial invoice, packing list, and HS code declaration (HS 9031.80) — is prepared in compliance with Chinese customs export regulations and destination-country import requirements. A 12-month warranty against manufacturing defects applies from the shipment date, with return authorization available within 30 days of receipt for units that fail incoming inspection at the customer’s facility.

Contact Information

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