Bently Nevada 330903-00-14-05-02-00 Proximity Probe – 3300 NSv Series

Bently Nevada 330903-00-14-05-02-00 — Eddy-Current Proximity Probe for Critical Rotating Machinery Protection

The Bently Nevada 330903-00-14-05-02-00 is an 8 mm eddy-current proximity probe belonging to the 3300 NSv (Non-contact Sensor) Series, a platform engineered specifically for continuous, real-time shaft vibration and axial position measurement in turbomachinery protection systems. This probe operates on the principle of electromagnetic induction: a high-frequency oscillator within the paired Proximitor sensor drives an alternating magnetic field through the probe tip coil. When a conductive target surface — typically a machined journal or thrust collar — enters the field, eddy currents are induced, loading the oscillator circuit and producing a DC output voltage linearly proportional to the gap distance. The 330903-00-14-05-02-00 is factory-calibrated for a nominal sensitivity of 7.87 V/mm (200 mV/mil) across a linear measurement range of 0 to 2 mm, with a system scale factor traceable to the paired 3300 XL 8 mm Proximitor sensor.

In a typical API 670-compliant machinery protection loop, this probe mounts radially or axially in a drilled and tapped boss on the bearing housing. The integral coaxial connector mates to a 330130-Series extension cable, which routes the signal to the 3300 XL Proximitor mounted outside the hazardous zone. The Proximitor conditions the raw oscillator signal into a buffered DC voltage output (−24 VDC bias nominal) and a buffered AC vibration signal, both of which feed directly into a Bently Nevada 3500 Series monitor rack for alarm and trip processing. The 330903-00-14-05-02-00 is a direct, calibrated drop-in replacement within any existing 3300 NSv system installation — no field recalibration of the monitor is required provided the extension cable length and Proximitor model are matched per the system calibration record.

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Technical Parameters

Hardware Logical Analysis

The 330903-00-14-05-02-00 probe tip houses a precision-wound, multi-layer coil encapsulated in a ceramic-filled epoxy compound within a 316 stainless steel housing. This construction achieves two simultaneous objectives: mechanical rigidity under the vibration loads present at bearing housings (typically 0.5–2 g broadband), and thermal stability of the coil inductance across the full −35°C to +177°C operating envelope. Inductance drift with temperature is the primary source of sensitivity error in eddy-current systems; the 3300 NSv coil geometry and encapsulant selection are matched to the 3300 XL Proximitor’s internal temperature compensation network, which applies a correction factor derived from a thermistor embedded in the Proximitor housing. The net result is a system sensitivity error of less than ±0.5% over the full temperature range when the probe, cable, and Proximitor are used as a calibrated set.

The integral 5 m armored cable uses a low-loss coaxial construction with a silver-plated copper center conductor and a braided shield providing greater than 90 dB of electromagnetic shielding effectiveness at 1 MHz. This is critical in plant environments where variable-frequency drives, high-current bus bars, and RF transmitters generate broadband EMI. The shield is grounded at the Proximitor end only (single-point grounding), preventing ground loop currents that would appear as low-frequency noise on the vibration signal. The cable armor — a stainless steel interlocked braid — provides mechanical protection against abrasion and incidental contact with rotating components during installation, while maintaining sufficient flexibility for routing through conduit bends with a minimum bend radius of 50 mm.

The probe tip geometry — 8 mm diameter, flat-face — is optimized for the standard API 670 Appendix D target surface specification: a minimum target diameter of 40 mm (5× probe tip diameter) and a minimum target thickness of 3 mm. Deviations from this specification, such as keyways, oil holes, or surface roughness exceeding Ra 1.6 µm, produce once-per-revolution electrical runout that is indistinguishable from mechanical vibration at the monitor. For installations where target surface quality is marginal, the 330903-00-14-05-02-00 can be used with a slow-roll compensation vector stored in the 3500 monitor to subtract the synchronous runout component from the overall vibration reading.

System Integration Benefits

• Zero mechanical contact, zero wear: The non-contact measurement principle eliminates any physical interaction with the rotating shaft. There is no sensor degradation mechanism tied to shaft speed or load cycles, making the probe suitable for continuous operation at shaft speeds from 0 RPM (static position measurement) to beyond 100,000 RPM in high-speed machinery.
• Deterministic frequency response: The 3300 NSv system has a flat frequency response from DC to 10 kHz (−3 dB), covering the full spectrum of interest in API 670 machinery protection: 0.5× sub-synchronous instability, 1× unbalance, 2× misalignment harmonics, and high-frequency blade-pass events.
• Dual-signal output architecture: The paired Proximitor provides both a buffered DC gap signal (for axial position and slow-roll orbit) and a buffered AC vibration signal simultaneously on separate output terminals, allowing the 3500 monitor to process both position and dynamic vibration from a single probe installation without additional hardware.
• Direct API 670 compliance: The probe, cable, and Proximitor combination is listed as a compliant transducer system under API 670 Fifth Edition, eliminating the engineering review burden required for non-listed sensors in regulated facilities such as LNG trains, refinery compressors, and power generation turbines.
• Calibrated system traceability: Each 330903-00-14-05-02-00 probe is factory-calibrated as part of a matched system (probe + cable + Proximitor). The calibration data — sensitivity, bias voltage at 1 mm gap, and linearity error — is documented on the system calibration sheet, providing the traceability record required by ISO 17025-accredited maintenance programs.
• Hazardous area compatibility: When used with the Bently Nevada 3300 Zener Barrier, the 330903-00-14-05-02-00 system meets ATEX and IECEx requirements for installation in Zone 1 and Zone 2 classified areas, covering the majority of hydrocarbon processing and chemical plant environments.
• Diagnostic transparency via 3500 monitor integration: The 3500 Series monitor continuously evaluates the probe gap voltage. A gap outside the linear range (probe too close or too far from the target) triggers a Not OK status output, providing immediate indication of probe failure, cable break, or shaft displacement beyond the measurement range — without requiring manual inspection.
• Minimal installation footprint: The 8 mm tip diameter and M10 × 1.0 thread (standard configuration) fit the industry-standard probe boss geometry used across virtually all OEM turbomachinery designs from the 1980s onward, enabling direct replacement without machining modifications to the bearing housing.
• Long-term spare parts availability: The 3300 NSv platform has been in continuous production for over two decades. The 330903-00-14-05-02-00 part number is a current, active catalog item — not an end-of-life or superseded reference — ensuring spare parts availability for the full operational life of the protected asset.

Quality Assurance & Global Logistics

Every Bently Nevada 330903-00-14-05-02-00 unit supplied by siemensplc.com is sourced through verified industrial supply channels and undergoes a structured incoming inspection protocol before dispatch. Physical inspection covers housing integrity, connector pin condition, cable sheath continuity, and label authenticity cross-referenced against current Bently Nevada OEM packaging standards. Lot traceability — including date code and country of manufacture — is recorded and archived. A Certificate of Conformance (COC) is available upon request for all orders, supporting the documentation requirements of ISO 9001-certified maintenance programs and regulated industries.

Logistics operations are based in Xiamen, China, a major southeastern port city with direct access to DHL Express, FedEx International Priority, and UPS Worldwide Expedited services. In-stock units are dispatched within 1–3 business days of order confirmation. Standard export documentation — commercial invoice, packing list, Certificate of Origin, and COC — is prepared as standard for all international shipments. For volume orders or project-based procurement requiring consolidated shipment, sea freight via Xiamen Port is available with competitive lead times to major global destinations. All shipments comply with Chinese export regulations and applicable destination-country import requirements. The 12-month warranty covers manufacturing defects and is supported by our technical team, reachable at [email protected].

Contact Information

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