Bently Nevada 330173-08-18-10-02-00 Proximity Probe – 3300 XL Series

Bently Nevada 330173-08-18-10-02-00 — 3300 XL 8 mm Eddy-Current Proximity Probe in Rotating Machinery Protection Loops

The Bently Nevada 330173-08-18-10-02-00 is an 8 mm eddy-current proximity probe belonging to the 3300 XL Proximity Transducer System. Within a machinery protection control loop, this probe functions as the primary sensing element responsible for converting mechanical shaft displacement into a calibrated DC voltage signal. The transducer operates on the eddy-current induction principle: a high-frequency oscillator (typically 1.0 MHz) drives the probe coil, generating an electromagnetic field that penetrates the target shaft surface. As the conductive target moves within the sensing field, eddy currents are induced, loading the oscillator circuit and producing a proportional change in output voltage at the Proximitor driver — nominally –200 mV/mil (–7.87 V/mm) for the 3300 XL system.

In a turbomachinery protection architecture, the 330173-08-18-10-02-00 is mounted radially at 90° X–Y orientation to measure shaft radial vibration (overall vibration amplitude and 1× synchronous component), or axially to track thrust position and differential expansion. The probe’s 8 mm tip diameter defines its linear sensing range: approximately 0.25 mm to 2.25 mm (10–90 mil) gap, which corresponds to the calibrated output window used by the downstream 3500 Series monitor to compute alarm and danger setpoints per API 670 Fifth Edition requirements. The 18-inch armored extension cable provides mechanical protection at the probe-to-Proximitor junction — a zone exposed to high vibration, thermal cycling, and process fluid contamination — while the 10-meter interconnect cable routes the signal from the machine casing to the Proximitor enclosure in the instrument cabinet.

This configuration (suffix -08-18-10-02-00) is factory-matched and calibrated as a system. Substituting individual components from different suffix families without recalibration will introduce scale factor errors and invalidate API 670 compliance. The probe, extension cable, and Proximitor must be treated as a matched set.

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Technical Parameters

Hardware Logical Analysis

Eddy-Current Field Geometry and Gap Linearity: The 8 mm coil geometry in the 330173 probe is wound to produce a sensing field depth of approximately 30% of the tip diameter — roughly 2.4 mm. This constrains the linear operating window to the 0.25–2.25 mm range cited above. Outside this window, the inductance-to-gap relationship becomes nonlinear, and the Proximitor’s output deviates from the –200 mV/mil scale factor. The factory calibration process characterizes each probe-extension-Proximitor set against a certified AISI 4140 target at controlled temperature, producing a calibration certificate that documents the actual scale factor and zero-gap intercept for that specific matched set.

Armored Extension Cable — Mechanical and Electrical Design: The 18-inch extension cable between the probe body and the interconnect cable junction serves two functions. Electrically, it is a precision coaxial transmission line with controlled characteristic impedance, matched to the probe coil’s RF circuit to prevent standing-wave reflections that would corrupt the oscillator loading signal. Mechanically, the armor braid provides resistance to abrasion, crush loads, and vibration-induced fatigue at the probe mounting bracket — a location that experiences the full vibration spectrum of the monitored machine. The armor construction also provides a degree of EMC shielding, attenuating radiated interference from adjacent high-current motor cables and variable-frequency drives.

EMC Design and Grounding Architecture: The 3300 XL system uses a single-point grounding scheme: the shield of the interconnect cable is grounded at the Proximitor end only, preventing ground loops that would introduce 50/60 Hz common-mode noise into the measurement. The probe body itself is electrically isolated from the machine casing via the mounting hardware, ensuring that shaft-to-casing ground potential differences do not appear as spurious vibration signals. In installations near high-power switchgear or VFDs, the 10-meter interconnect cable’s coaxial construction provides >60 dB of common-mode rejection across the 10 Hz – 10 kHz measurement bandwidth.

Thermal Stability: The probe coil is wound on a ceramic bobbin with a low thermal coefficient of inductance. Over the –35 °C to +177 °C operating range, the scale factor variation is specified at ±1% of reading — a critical parameter for axial position measurements where a 0.1 mm thrust position error can represent the difference between a normal operating condition and an imminent thrust bearing failure alarm.

Target Material Sensitivity: The eddy-current field interacts with the electrical conductivity and magnetic permeability of the target. The 3300 XL system is calibrated against AISI 4140 steel. Shafts machined from alternative alloys (e.g., 17-4 PH stainless, Inconel 718) exhibit different conductivity-permeability products, shifting the effective scale factor by 5–15%. Bently Nevada publishes correction factors for common alternative target materials; these must be applied during commissioning to maintain measurement accuracy within API 670 tolerances.

System Integration Benefits

• Direct API 670 Compliance Path: The 330173-08-18-10-02-00, when paired with the compatible 02-series 3300 XL Proximitor and a 3500 Series monitor, forms a complete API 670-compliant measurement channel. No additional signal conditioning is required to meet the standard’s accuracy, bandwidth, and self-test requirements.
• Deterministic Real-Time Response: The eddy-current measurement chain has a flat frequency response from DC to beyond 10 kHz, capturing shaft vibration components from slow-roll (below 1 Hz) through high-frequency subsynchronous instabilities and blade-pass frequencies without phase distortion or amplitude roll-off within the measurement band.
• Non-Contact Operation Eliminates Wear-Induced Drift: Unlike contact-type displacement sensors, the eddy-current probe introduces zero mechanical load on the shaft and exhibits no wear-related scale factor drift over its service life. Long-term measurement stability is governed by coil aging and cable dielectric stability — both characterized over decades of field deployment in the 3300 XL platform.
• Integrated Self-Test via Proximitor OK Circuit: The 3300 XL Proximitor continuously monitors the probe circuit for open-circuit and short-circuit faults, driving the OK relay output to the de-energized (fault) state when a cable break or probe failure is detected. This provides automatic diagnostic transparency to the 3500 Series monitor and the plant DCS without requiring manual intervention.
• Seamless DCS/PLC Integration: The Proximitor’s –24 VDC output signal interfaces directly with the 3500 Series monitor’s input cards, which provide 4–20 mA and relay outputs for integration with Siemens PCS 7, Emerson DeltaV, Honeywell Experion, ABB 800xA, and other major DCS platforms. No intermediate signal converter is required.
• Matched-Set Calibration Traceability: Each 330173-08-18-10-02-00 assembly ships with a factory calibration certificate traceable to NIST standards. This documentation supports ISO 9001 and ISO 55001 asset management requirements and simplifies regulatory audits in nuclear, offshore, and petrochemical facilities.
• Drop-In Replacement Without Monitor Reconfiguration: Replacing a failed 330173-08-18-10-02-00 with an identical suffix unit requires no changes to the 3500 Series monitor configuration, alarm setpoints, or DCS tag assignments — provided the replacement unit’s calibration certificate confirms a scale factor within ±1% of the original. This minimizes planned maintenance window duration.
• Redundancy Architecture Support: In dual-voting (2oo2) or triple-redundant (2oo3) machinery protection configurations, the 330173-08-18-10-02-00 can be deployed as one of multiple independent measurement channels on the same shaft journal. The probe’s compact 8 mm tip diameter allows installation in confined bearing housings where larger probes cannot be accommodated.

Quality Assurance & Global Logistics

Every Bently Nevada 330173-08-18-10-02-00 unit supplied by siemensplc.com is sourced through verified supply channels with full documentation traceability. Prior to dispatch from our Xiamen, China facility, each unit undergoes visual inspection for label authenticity, connector integrity, and cable armor condition. Serial numbers and date codes are cross-referenced against available manufacturer records. Units are packaged in anti-static, shock-resistant materials with desiccant to prevent moisture ingress during international transit.

From Xiamen, we ship globally via DHL Express, FedEx International Priority, and UPS Express — with typical transit times of 3–5 business days to Europe, the Middle East, and Southeast Asia, and 5–7 business days to North and South America. Full export documentation is provided with every shipment: commercial invoice, packing list, certificate of origin, and any additional customs declarations required by the destination country. Our team has direct experience with export compliance for industrial automation components to over 40 countries, including ECCN classification and dual-use export screening.

All units are covered by a 12-month warranty from the date of shipment. Warranty claims are processed within 5 business days of receipt of the returned unit, with replacement or credit issued upon confirmation of the defect. Emergency replacement shipments can be arranged within 24 hours for in-stock units when plant downtime is at risk.

Contact Information

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