Bently Nevada 330171-08-24-10-02-00 Proximity Probe – 3300 XL Series

Bently Nevada 330171-08-24-10-02-00 — 8 mm Eddy-Current Proximity Probe in the 3300 XL Matched System Architecture

The 330171-08-24-10-02-00 is an 8 mm diameter, non-contacting eddy-current proximity probe manufactured by Bently Nevada as a core sensing element within the 3300 XL matched measurement system. It is engineered for continuous shaft vibration, radial position, and axial displacement monitoring in API 670-compliant machinery protection installations. The probe ships as a complete assembly: a 24-inch (610 mm) armored extension cable is factory-terminated to the probe body, forming a calibrated two-component sub-assembly that mates with a 3300 XL 8 mm Proximitor to complete the three-component measurement chain.

In turbomachinery protection, the proximity probe is the first transducer in the signal path. Its output fidelity determines the accuracy of every downstream alarm and trip decision. The 330171 series achieves a nominal scale factor of 7.87 V/mm (200 mV/mil) against AISI 4140 or 4340 steel targets, with a linear measurement range of 0.25 mm to 2.25 mm (10 to 90 mil). Frequency response extends from DC to 10,000 Hz, covering synchronous 1X/2X vibration components, sub-synchronous instability, and high-frequency gear mesh events within a single transducer bandwidth.

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Technical Parameters

Hardware Logical Analysis

The 330171-08-24-10-02-00 operates on the principle of electromagnetic induction. An oscillator circuit within the 3300 XL Proximitor drives a high-frequency carrier signal — nominally 1.0 MHz — through the coaxial cable to the probe tip coil. The coil generates a focused electromagnetic field that penetrates the surface of the rotating target shaft. When a conductive target enters the field, eddy currents are induced in the target surface, absorbing energy from the probe coil and reducing its effective impedance. The Proximitor’s demodulation circuit converts this impedance change into a DC output voltage proportional to the probe-to-target gap.

EMC Design: The armored stainless steel braid over the PTFE-insulated coaxial core provides a continuous Faraday shield from the probe tip connector to the Proximitor input. This construction attenuates capacitively coupled interference from adjacent VFD power cables, motor windings, and high-voltage bus bars — environments common in compressor trains and turbine halls. The shield is grounded at the Proximitor end only (single-point grounding) to prevent shield current loops that would introduce 50/60 Hz noise into the measurement signal.

Thermal Stability: The probe body is machined from 316 stainless steel, which exhibits a low and predictable coefficient of thermal expansion. The PTFE dielectric in the coaxial cable maintains stable electrical characteristics across the full –35°C to +121°C cable operating range. At the probe tip, the coil former material is selected for dimensional stability at the rated +177°C body temperature, preventing gap measurement drift caused by thermal expansion of the probe structure itself.

Matched System Calibration: The 330171 probe is factory-characterized as part of a matched set with a specific 3300 XL Proximitor. The scale factor of 7.87 V/mm is verified against a certified AISI 4140 target at 25°C. API 670 Annex D requires that the complete three-component system (probe + extension cable + proximitor) be calibrated together, because the total cable capacitance and inductance affect the oscillator loading and therefore the scale factor. Substituting any component from a different matched set without recalibration introduces systematic measurement error that cannot be corrected by monitor card gain adjustments alone.

Connector Integrity: The 10-32 UNF coaxial connector uses a precision-machined center pin and PTFE dielectric insert. The impedance is controlled to 50 Ω through the connector body to maintain signal integrity at the 1 MHz carrier frequency. Connector mating torque is specified at 0.9 N·m (8 in-lb); over-torquing deforms the PTFE insert and shifts the connector impedance, introducing reflections that appear as noise on the demodulated output.

System Integration Benefits

• Zero-wear measurement path: The non-contacting eddy-current principle eliminates mechanical contact between the probe and the rotating shaft. There is no friction, no wear particle generation, and no scheduled replacement interval driven by probe degradation — the probe remains in service until the machinery is taken offline for planned maintenance.
• DC-to-10 kHz bandwidth in a single transducer: The flat frequency response from DC allows simultaneous measurement of static shaft position (gap) and dynamic vibration without separate transducers. This eliminates the need for a separate position sensor on machines where both radial vibration and thrust position must be monitored at the same bearing location.
• Direct API 670 compliance: Deploying the 330171 in an existing 3300 XL system requires no re-certification of the measurement loop. The probe meets API 670 5th Edition transducer requirements for sensitivity, linearity, and temperature range, allowing direct substitution in SIS-classified machinery protection systems without a management-of-change (MOC) review for the transducer specification.
• Plug-compatible with 3300 XL and 3500 series monitors: The Proximitor output (–2 VDC to –18 VDC at 200 mV/mil) is the standard input signal for Bently Nevada 3500/40M, 3500/42M, and 3500/45 monitor cards. No signal conditioning, scaling, or input card reconfiguration is required when replacing a probe in an existing installation.
• IP67 ingress protection at the probe body: The sealed probe body and connector withstand wash-down, oil mist, and condensation in bearing housings and turbine pedestals. This eliminates the need for additional protective enclosures around the probe mounting boss in most industrial environments.
• High-temperature bearing pedestal capability: The +177°C probe body rating covers the bearing pedestal temperatures encountered on HP steam turbine casings and gas turbine compressor discharge sections, where bearing metal temperatures can reach 150–160°C under full-load conditions.
• Deterministic signal latency: The eddy-current measurement chain introduces no digital processing delay between shaft motion and the Proximitor output voltage. The analog output tracks shaft position in real time, ensuring that the 3500 monitor’s trip relay responds within its specified 1 ms processing cycle without additional transducer-induced latency.
• Diagnostic transparency via gap voltage monitoring: The Proximitor output voltage at static conditions (machine at rest, shaft centered) provides a direct, measurable indication of probe-to-shaft gap. Maintenance engineers can verify probe installation gap (target: 1.0 mm / –10.2 VDC for 8 mm system) with a standard DVM at the Proximitor output terminals, without removing the probe or interrupting the measurement loop.

Quality Assurance & Global Logistics

Every 330171-08-24-10-02-00 unit offered through siemensplc.com is sourced as genuine Bently Nevada (Baker Hughes) manufacture. Units are procured through verified industrial distribution channels with full supply chain traceability. Prior to listing, each assembly undergoes incoming inspection covering connector pin integrity, cable continuity and shield resistance, probe body thread condition, and visual inspection of the tip coil area for mechanical damage. Units that fail any inspection criterion are quarantined and removed from available stock — they are not offered for sale at any price.

Calibration certificates, material test reports (MTR), and certificates of conformance (CoC) are available upon request for critical-service and SIS applications. Serialized units with traceable manufacturing batch records are prioritized for customers with documentation requirements.

Dispatch is handled from our Xiamen, China operations center. Xiamen is a designated free-trade port with direct air freight connections to major industrial hubs: Singapore, Dubai, Rotterdam, Houston, and Tokyo. Standard in-stock orders ship within 3–5 business days via DHL Express, FedEx International Priority, or UPS Worldwide Expedited, with full commercial invoice, packing list, and airway bill documentation. For customers requiring EXW, CIF, or DAP Incoterms, these are available on request at the quotation stage. Customs clearance documentation — including HS code classification, country of origin declaration, and CITES/dual-use compliance statements where applicable — is prepared by our logistics team for each shipment.

A 12-month warranty covers manufacturing defects in materials and workmanship from the date of dispatch. Warranty claims are processed with a replacement-first policy: a replacement unit is dispatched upon receipt of the defective unit and completion of incoming inspection at our facility.

Contact Information

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