Bently Nevada 330103-10-20-05-02-CN Proximity Probe – 3300 XL

Bently Nevada 330103-10-20-05-02-CN: Eddy-Current Proximity Probe for API 670 Machinery Protection Systems

The 330103-10-20-05-02-CN is a factory-configured 8 mm eddy-current proximity probe within Bently Nevada’s 3300 XL Proximity Transducer System. Its function is singular and non-negotiable in rotating machinery protection: it converts the physical gap between probe tip and target shaft surface into a calibrated DC voltage signal, delivering continuous, non-contact measurement of radial shaft vibration and axial position with a scale factor of 200 mV/mil (7.87 V/mm). This signal feeds directly into the Bently Nevada 3500 Series Machinery Protection System or equivalent monitoring rack, where it drives alarm and trip logic that protects turbines, compressors, and pumps from catastrophic mechanical failure.

The part number encodes the full mechanical and electrical configuration: 10 mil nominal gap, 2.0 m integral cable, 5 mm probe body thread, reverse-mount (02) connector exit, and CN connector type. This specific geometry is specified in OEM documentation for installations where forward-exit cable routing conflicts with bearing housing geometry — a common constraint in steam turbine bearing pedestals and integrally geared compressor casings. The reverse-mount exit routes the cable axially away from the probe tip, reducing mechanical stress on the cable at the connector junction and simplifying cable management in confined spaces.

Within the 3300 XL system architecture, the probe operates as the passive sensing element. It is driven by the 3300 XL NSv Proximitor® Sensor, which supplies the 1 MHz oscillator signal through the integral cable and returns the demodulated DC output voltage proportional to gap. The probe’s 8 mm tip diameter defines the eddy-current field geometry, establishing the linear measurement range of 10–90 mil (0.25–2.29 mm) and the target material sensitivity. Per API 670 Annex D, the target shaft material must be AISI 4140 steel or equivalent to maintain the published scale factor within ±1% across the linear range.

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Technical Parameters

Hardware Logical Analysis

The 3300 XL 8 mm probe operates on the Lenz’s Law eddy-current principle. The Proximitor® Sensor drives a 1 MHz sinusoidal current through the probe coil, generating an alternating magnetic field at the probe tip. When a conductive target enters this field, eddy currents are induced on the target surface, loading the probe coil and reducing its effective inductance and Q-factor. The Proximitor® demodulates this impedance change into a DC voltage output: as the gap decreases, the output voltage becomes more negative (typically –24 VDC supply, output range –2 to –18 VDC across the linear range).

EMC Design: The probe coil is wound on a ferrite core and enclosed in a stainless steel housing with a hermetic epoxy seal at the cable exit. This construction provides inherent shielding against capacitive coupling from adjacent high-voltage cables — a critical requirement in turbine bearing pedestals where proximity probe cables run parallel to thermocouple and power wiring. The coaxial cable construction (inner conductor, dielectric, shield, outer jacket) maintains signal integrity over the 2.0 m integral cable length, with the shield grounded at the Proximitor® end only to prevent ground loop interference.

Reverse-Mount Connector Logic: The 02 exit designation routes the cable 180° from the probe tip axis. This is not merely a mechanical convenience — it eliminates the bending radius constraint at the connector junction that occurs with forward-exit probes in tight housings. In installations where the probe is threaded into a bearing housing boss with less than 30 mm of clearance above the connector, a forward-exit cable would require a sharp bend immediately at the connector, creating a fatigue point subject to vibration-induced failure. The reverse-mount geometry eliminates this failure mode entirely.

Thermal Stability: The probe’s scale factor is specified at 25°C and compensated across the operating range. At the upper limit of 177°C (probe body), the ferrite core permeability decreases, which would shift the resonant frequency of the probe-Proximitor® system. Bently Nevada’s matched-system calibration — where the probe, extension cable, and Proximitor® are calibrated as a set — accounts for this thermal drift, maintaining measurement accuracy within the published ±1% scale factor tolerance across the full temperature range.

System Integration Benefits

• Non-Contact Measurement Eliminates Wear: The eddy-current sensing principle requires zero mechanical contact with the rotating shaft. There is no wear mechanism, no lubrication requirement, and no periodic replacement interval driven by contact fatigue — the probe service life is limited only by environmental degradation of the cable jacket and connector.
• DC-to-10 kHz Bandwidth Captures Full Vibration Spectrum: The flat frequency response from DC to 10,000 Hz allows simultaneous measurement of slow-roll runout (near-DC), 1× and 2× synchronous vibration, sub-synchronous instability (oil whirl/whip at 0.43–0.48×), and high-frequency structural resonances — all from a single probe channel without signal conditioning changes.
• Direct 3500 Series Rack Compatibility: The 330103-10-20-05-02-CN is a drop-in replacement within any existing 3300 XL system installation. The Proximitor® Sensor does not require recalibration when replacing a probe of identical part number, reducing maintenance downtime to the time required for physical probe replacement and gap setting.
• API 670 Compliance Simplifies Engineering Documentation: Specifying an API 670-compliant transducer system eliminates the need for custom acceptance testing in regulated industries. The probe’s compliance with API 670 Annex D target material requirements and Annex E calibration procedures is documented in Bently Nevada’s published datasheets, directly satisfying EPC contractor and operator quality requirements.
• Deterministic Output Signal for Trip Logic: The Proximitor® output is a low-impedance DC voltage signal (output impedance <100 Ω), immune to the noise pickup that affects high-impedance piezoelectric accelerometer signals in electrically noisy environments. This deterministic signal characteristic is essential for machinery protection trip circuits where false trips carry significant operational cost.
• Dual-Purpose Measurement (Vibration + Position): A single 330103-10-20-05-02-CN channel can simultaneously provide radial vibration (AC component, filtered above 1 Hz) and average shaft centerline position (DC component) to the monitoring system. This eliminates the need for separate position sensors in applications where both parameters are required for machinery health assessment.
• Hazardous Area Certification Reduces Zener Barrier Complexity: The ATEX/IECEx certification of the 3300 XL system, when used with the appropriate Zener barrier or galvanic isolator, allows installation in Zone 1/Zone 2 hazardous areas without custom intrinsic safety calculations, accelerating project engineering timelines.
• Matched-System Calibration Traceability: Each 3300 XL probe is calibrated as part of a matched system (probe + extension cable + Proximitor®). The calibration data is traceable to NIST standards, satisfying the measurement traceability requirements of ISO 9001-certified maintenance programs and regulated industries such as nuclear power and offshore oil & gas.

Quality Assurance & Global Logistics

Every 330103-10-20-05-02-CN unit shipped from our Xiamen, China facility is sourced directly from authorized Bently Nevada (Baker Hughes) distribution channels. Each unit arrives in original OEM packaging with intact factory seals, date codes, and serialization. Before dispatch, our technical team performs a multi-point verification protocol: part number and date code authentication against OEM documentation, physical inspection of the probe tip, cable jacket, and CN connector for mechanical integrity, and impedance continuity verification of the probe coil circuit.

Packaging is engineered for international transit: anti-static inner wrap, closed-cell foam suspension, and a rigid outer carton rated for air freight handling. Humidity indicator cards are included for shipments to tropical and high-humidity destinations. Export documentation — commercial invoice, packing list, certificate of origin, and certificate of conformance — is prepared to the standards required by customs authorities in the EU, North America, Southeast Asia, and the Middle East.

Standard international dispatch from Xiamen is 3–5 business days for in-stock units via DHL Express, FedEx International Priority, or UPS Worldwide Expedited, with tracking provided at time of shipment. For urgent plant maintenance requirements, same-day dispatch is available for orders confirmed before 14:00 CST. Volume orders for OEM and EPC procurement programs are supported with consolidated shipment scheduling and advance shipping notifications (ASN) compatible with SAP and Oracle ERP receiving workflows.

Contact Information

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