Bently Nevada 330103-00-03-05-02-02 Proximity Probe – 3300 XL Series

Bently Nevada 330103-00-03-05-02-02 — 8mm Eddy Current Proximity Probe in the 3300 XL Transducer System

The Bently Nevada 330103-00-03-05-02-02 is an 8 mm eddy-current proximity probe operating within the 3300 XL Transducer System — a platform that has defined the machinery protection standard for turbomachinery since the 1990s. This specific configuration encodes a metric M10 × 1 thread body, a 5-metre integral coaxial cable, and a BNC pre-terminated connector, making it a direct, no-rework replacement in installations originally built to that specification.

In a rotating machinery protection loop, the proximity probe is the first element in the signal chain. Its output — a DC-biased voltage that shifts linearly with gap distance — feeds the Proximitor driver, which in turn delivers a conditioned signal to the monitor rack (3500/42 or 3500/40M). Any deviation in probe sensitivity, cable impedance, or connector integrity propagates directly into the monitor’s alarm and trip logic. Specifying the factory-calibrated OEM part eliminates the recalibration overhead that third-party substitutes impose on commissioning teams.

The probe’s eddy-current operating principle is inherently non-contact: a high-frequency oscillator (typically 1.0 MHz carrier) drives a coil wound at the probe tip. When a conductive target — shaft or thrust collar — enters the electromagnetic field, induced eddy currents load the coil, reducing oscillation amplitude. The Proximitor linearises this amplitude change into the standard 7.87 V/mm (200 mV/mil) output. Because no mechanical contact occurs, wear is zero and the measurement bandwidth extends from DC to 10,000 Hz, capturing both slow-roll runout and high-frequency sub-synchronous instabilities.

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Technical Parameters

Hardware Logical Analysis

Coil Geometry and Gap Linearity: The 8 mm tip diameter is a deliberate engineering choice. A smaller coil (5 mm, 330101 series) concentrates the electromagnetic field over a narrower target zone, increasing sensitivity to surface irregularities but reducing the usable linear range. The 8 mm coil achieves a 2.29 mm linear span — sufficient to capture both normal operating eccentricity and alarm-level shaft displacement without saturating the Proximitor’s input stage. The coil winding geometry is encapsulated in a ceramic-filled epoxy compound rated to 177 °C, preventing thermal expansion from altering coil inductance and shifting the calibration curve.

Cable Impedance Matching: The integral 5-metre coaxial cable is manufactured to a controlled characteristic impedance matched to the 3300 XL Proximitor input. Any impedance discontinuity — caused by a field splice, incompatible extension cable, or damaged connector — introduces reflections at the carrier frequency that appear as a sensitivity offset. The factory-terminated BNC connector on this model eliminates the most common field-splice failure point. The PTFE-insulated inner conductor maintains dielectric stability across the full operating temperature range, preventing capacitance drift that would otherwise shift the gap-voltage curve.

EMC Design: The armoured coaxial construction provides continuous 360° shielding from the probe tip to the BNC connector. The shield is grounded at the Proximitor end only (single-point grounding), preventing ground-loop currents from injecting common-mode noise into the measurement signal. In high-EMI environments — adjacent VFDs, large motor starters, or arc furnaces — this shielding architecture maintains signal integrity without requiring additional conduit or ferrite suppression.

Thermal Stability: The probe body is machined from 316 stainless steel, which has a coefficient of thermal expansion (CTE) of approximately 16 µm/m·°C. The ceramic-epoxy tip encapsulant is formulated to match this CTE closely, preventing differential expansion from mechanically stressing the coil winding at temperature extremes. This is particularly relevant in hot-section turbine bearing pedestals where ambient temperatures can reach 150 °C continuously.

Target Material Sensitivity: The standard factory calibration assumes AISI 4140 steel (relative permeability µr ≈ 100, electrical conductivity σ ≈ 4.0 MS/m). For non-standard target materials — 17-4 PH stainless, Inconel 718, or titanium alloys — the eddy-current penetration depth and loss factor differ, shifting the effective sensitivity by 5–25%. Bently Nevada publishes target material correction factors; these must be applied to the Proximitor’s gap voltage setpoints during commissioning if the shaft material deviates from 4140 steel.

System Integration Benefits

• Zero-recalibration replacement: Factory sensitivity of 7.87 V/mm is matched to the 3300 XL Proximitor’s internal reference. Swapping this probe into an existing installation requires only a gap-voltage verification check — no monitor card rescaling or software parameter changes.
• DC-to-10 kHz bandwidth: The flat frequency response from DC captures slow-roll vectors (used for runout subtraction) while the 10 kHz upper limit resolves blade-pass frequencies on compressors with up to 600 blades at 1,000 RPM, enabling sub-synchronous instability detection without aliasing.
• API 670 compliance: The probe meets the Machinery Protection Systems standard required by most EPC contractors and plant operators in oil & gas and petrochemical facilities. Compliance documentation is available for HAZOP and SIL assessment packages.
• Deterministic signal latency: The eddy-current measurement is an analogue, continuous-time signal. There is no A/D conversion or digital processing latency in the probe itself. The monitor rack samples at ≥51,200 samples/second, giving a worst-case measurement latency of <20 µs — well within the response time budget of API 670 trip logic.
• Diagnostic transparency via gap voltage: The Proximitor’s DC output voltage at the operating gap (nominally –10 to –18 VDC) is directly readable on a multimeter. A technician can verify probe health, cable continuity, and correct installation gap without specialist tools or software — a significant advantage during shutdown maintenance windows.
• Compatibility with System 1 software: When connected through the 3500 rack, the probe’s signal feeds Bently Nevada System 1 condition monitoring software, enabling waveform capture, orbit plots, and trend analysis. The OEM part ensures the sensitivity constant stored in System 1’s database matches the physical hardware, preventing false alarm conditions from calibration mismatches.
• Redundant measurement configurations: Two 330103-00-03-05-02-02 probes installed at 90° (X–Y configuration) on the same bearing journal provide a complete orbit plot. The 3500/42 module supports voting logic between the two channels, so a single probe failure does not cause a spurious trip — it generates a sensor fault alarm while the second channel maintains protection.
• Hazardous area suitability: The probe carries CE marking and is compatible with ATEX-certified Proximitor drivers for Zone 1/Zone 2 installations. The passive probe itself contains no active electronics, simplifying the ATEX entity parameter calculation for the overall loop.

Quality Assurance & Global Logistics

Every 330103-00-03-05-02-02 unit supplied by siemensplc.com is sourced from authorised Bently Nevada (Baker Hughes) distribution channels or verified OEM-surplus inventories with full chain-of-custody documentation. Pre-shipment inspection covers visual examination against OEM dimensional drawings, coaxial cable continuity and insulation resistance measurement, BNC connector torque verification, and serialised calibration certificate cross-check.

Units are packed in anti-static foam-lined cases with individual moisture-barrier bags and desiccant packs, meeting ASTM D4169 performance level II for air freight. Export documentation — commercial invoice, packing list, and Certificate of Conformance — is prepared to comply with Chinese customs export regulations and destination-country import requirements.

Shipments originate from our warehouse in Xiamen, China. Standard air freight to major industrial hubs: Singapore 2–3 days, Dubai 3–4 days, Rotterdam 4–5 days, Houston 5–6 days. DHL Express and FedEx Priority accounts are maintained for shutdown-critical orders requiring next-flight-out dispatch. All shipments are fully insured and tracked door-to-door. A 12-month warranty against manufacturing defects is provided from the date of shipment; warranty claims are processed within 5 business days.

Contact Information

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