Bently Nevada 330851-02-000-030-10-00-00 Proximity Probe – 3300 XL Series

Bently Nevada 330851-02-000-030-10-00-00 — 8 mm Eddy-Current Proximity Probe in the 3300 XL Transducer System

The Bently Nevada 330851-02-000-030-10-00-00 is an 8 mm eddy-current proximity probe belonging to the 3300 XL Proximity Transducer System, a platform engineered specifically for continuous, non-contact measurement of shaft radial vibration, axial position, and differential expansion on critical rotating machinery. Unlike piezoelectric accelerometers that respond to acceleration, this probe operates on the eddy-current induction principle: a high-frequency oscillating magnetic field generated at the probe tip induces circulating currents in the conductive target surface; the impedance change caused by gap variation is demodulated by the paired driver into a DC-proportional voltage output. This mechanism delivers a flat frequency response from DC (0 Hz) to beyond 10 kHz, making it uniquely suited for capturing both static position offset and dynamic vibration simultaneously — a capability that no contact-type transducer can replicate on a spinning shaft.

The probe body is machined from 316 stainless steel with a PEEK (polyether ether ketone) tip housing, providing chemical resistance against hydrocarbon condensates, lube oil, and steam environments common in turbomachinery enclosures. The integral 2-metre coaxial cable is terminated with a MIL-C-17-compliant connector, ensuring low-loss signal transmission to the extension cable junction. The entire assembly is factory-calibrated as a matched set with the 3300 XL 8 mm driver, with sensitivity traceable to NIST standards at 7.87 V/mm (200 mV/mil) ± 1% across the linear measurement range of 0.25 mm to 2.29 mm (10 to 90 mil).

In API 670-compliant machinery protection architectures, this probe feeds directly into Bently Nevada 3500 Series monitors — including the 3500/40M, 3500/42M, 3500/45, and 3500/46M — where the conditioned voltage signal is processed against user-configured alert and danger setpoints. The monitor’s internal voting logic can trigger relay outputs to initiate controlled shutdowns within milliseconds of a threshold crossing, a deterministic response that is foundational to turbine and compressor protection philosophy.

Real-time Stock & RFQ: [email protected] | WhatsApp: +86 18359268345

Technical Parameters

Hardware Logical Analysis

The 330851-02-000-030-10-00-00 probe’s internal LC oscillator circuit operates at approximately 1 MHz. The coil geometry — a multi-layer, close-wound solenoid embedded in the PEEK tip — is precision-wound to achieve a tightly controlled inductance value that, when combined with the tuning capacitor network inside the driver, establishes the resonant frequency of the complete transducer system. This matched-set architecture is not incidental: any substitution of probe or extension cable without recalibration shifts the resonant point, introducing non-linearity errors that can exceed ±5% at the extremes of the measurement range.

EMC Design: The coaxial cable construction provides inherent electrostatic shielding (shield coverage >95%), and the MIL-C-17 connector maintains shield continuity through the junction to the extension cable. In high-EMI environments — such as variable-frequency drive (VFD) motor rooms or switchgear enclosures — the coaxial architecture suppresses common-mode interference that would otherwise corrupt the low-level oscillator signal. The driver’s demodulation stage further applies a low-pass filter with a selectable corner frequency (typically 10 kHz), attenuating RF pickup above the machinery vibration spectrum.

Thermal Stability: The PEEK tip material has a coefficient of thermal expansion (CTE) of approximately 50 ppm/°C, significantly lower than nylon or PTFE alternatives. This dimensional stability ensures that the probe-to-target gap does not drift with enclosure temperature changes, preserving measurement baseline integrity across the full −35 °C to +177 °C operating envelope. For applications near steam seals or exhaust casings where temperatures approach the upper limit, the probe’s stainless steel body acts as a thermal barrier, protecting the coil assembly from conductive heat transfer.

Mechanical Mounting Integrity: The M10 × 1.0 thread with a 17 mm hex flat allows installation with a calibrated torque wrench. The probe includes a locknut to prevent vibration-induced backing-out — a critical detail in high-cycle fatigue environments such as compressor bearing housings where shaft rotational frequencies can exceed 300 Hz. The probe tip recess geometry is designed so that the active sensing face is recessed 0.5 mm from the mounting bracket face, preventing accidental contact with the shaft during coastdown events.

System Integration Benefits

• DC-coupled measurement path: The eddy-current principle captures both static position (DC component) and dynamic vibration (AC component) in a single channel, eliminating the need for separate position and vibration transducers on the same bearing journal.
• Deterministic latency: Signal propagation from probe tip to driver output is governed by the LC circuit time constant, typically <100 µs, ensuring that the 3500 monitor receives a real-time representation of shaft position with no algorithmic delay introduced by digital sampling.
• Matched-set calibration traceability: Each probe ships with a calibration certificate referencing the specific driver and extension cable serial numbers used during factory calibration, enabling full measurement uncertainty budgeting per ISO/IEC 17025 requirements.
• Diagnostic transparency via gap voltage: The raw DC output voltage from the driver is directly proportional to the air gap. Maintenance engineers can verify probe health and mounting gap with a standard voltmeter — no proprietary diagnostic tool required. A reading of −10.16 VDC at the driver output confirms a nominal 1.27 mm gap on a 4140 steel target.
• Seamless 3500 monitor integration: The probe’s output range (−2 V to −18 V) maps directly to the input specifications of the 3500/40M and 3500/42M radial vibration monitors without signal conditioning adapters, reducing wiring complexity and potential signal degradation points.
• API 670 fifth-edition compliance: The 3300 XL system meets the transducer performance requirements of API 670 (Machinery Protection Systems), including sensitivity tolerance, frequency response, and temperature range, supporting compliance documentation for new installations and insurance audits.
• Redundant channel support: Two probes mounted 90° apart (X-Y configuration) on the same bearing journal feed independent monitor channels, enabling the 3500 monitor’s voting logic to distinguish between true shaft orbit and single-channel faults — a redundancy architecture that reduces spurious shutdowns without compromising protection integrity.
• DCS integration via standard analog output: The driver’s −2 V to −18 V output is converted to a 4–20 mA signal by the 3500 monitor’s analog output card, enabling direct integration with DeltaV, Ovation, ABB 800xA, or any HART-compatible DCS historian without additional signal converters.

Quality Assurance & Global Logistics

Every Bently Nevada 330851-02-000-030-10-00-00 unit stocked at our Xiamen, China facility undergoes a structured incoming inspection protocol before entering inventory. This includes visual examination of the probe tip and cable jacket for mechanical damage, continuity and insulation resistance testing of the coaxial cable (IR >100 MΩ at 500 VDC), and verification of the MIL-C-17 connector pin engagement force. Units sourced from authorized distribution channels are accompanied by original Baker Hughes packing documentation and, where available, factory calibration certificates with serial number traceability.

Packaging follows anti-static and moisture-barrier standards: each probe is individually wrapped in ESD-safe foam, sealed in a moisture-proof poly bag with desiccant, and placed in a rigid corrugated carton with impact-absorbing inserts. This packaging protocol is designed to survive the mechanical shock and humidity variations of international air freight without compromising the probe’s calibrated coil geometry.

From Xiamen, we dispatch via DHL Express, FedEx International Priority, and UPS Worldwide Expedited, with typical transit times of 3–5 business days to Europe and North America, and 2–3 business days to Southeast Asia. For bulk orders exceeding 20 units, sea freight consolidation via Xiamen Port is available with full export documentation including commercial invoice, packing list, and certificate of origin. All shipments are covered by cargo insurance, and tracking numbers are provided within 24 hours of dispatch.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
© 2026 siemensplc.com. All rights reserved.