Bently Nevada 330905-00-07-10-02-05 Proximity Probe – 3300 XL Series

Bently Nevada 330905-00-07-10-02-05 — Eddy-Current Proximity Probe for Turbomachinery Shaft Monitoring

In rotating machinery protection, the proximity probe is the first and most critical sensing element in the measurement chain. The Bently Nevada 330905-00-07-10-02-05 is a 7.87 mm (5/16 in) diameter, 1-metre integral-cable eddy-current probe engineered for the 3300 XL Series Proximitor® system. It delivers continuous, non-contact measurement of radial shaft vibration, relative shaft position, and axial displacement — parameters that define the mechanical health of turbines, compressors, pumps, and gearboxes operating under sustained dynamic load.

This probe is specified in OEM documentation for machinery from GE, MAN Energy Solutions, Solar Turbines, and Siemens Energy, and is deployed across oil & gas, power generation, petrochemical refining, and heavy industrial facilities worldwide. Its dimensional and electrical characteristics conform to API Standard 670, the governing specification for machinery protection instrumentation in process industries.

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

Technical Parameters

Hardware Logical Analysis

The 330905-00-07-10-02-05 operates on the principle of electromagnetic induction. The probe tip contains a wound coil driven by a high-frequency oscillator (typically 1.0 MHz) housed within the matched Proximitor® sensor. When the probe tip is positioned within its linear range of a conductive target, eddy currents are induced on the target surface. These currents create a secondary magnetic field that opposes the probe’s primary field, reducing coil impedance in proportion to the gap distance. The Proximitor® demodulates this impedance change into a DC voltage output: −24 VDC at maximum gap, scaling linearly toward 0 VDC as the gap closes.

EMC Design: The coaxial cable construction — with a continuous braided shield referenced to the Proximitor® common — provides inherent rejection of capacitively coupled interference. The shield is grounded at the Proximitor® end only, preventing ground-loop currents that would introduce 50/60 Hz noise into the measurement signal. In high-EMI environments such as variable-frequency drive (VFD) motor rooms or switchgear enclosures, this single-point grounding topology maintains signal integrity without additional filtering.

Thermal Stability: The probe body is machined from 316 stainless steel, which exhibits a coefficient of thermal expansion (CTE) of approximately 16 µm/m·°C. The coil former material is selected to minimize differential thermal expansion between the winding and the housing, preserving calibration accuracy across the full −35 °C to +177 °C operating envelope. This is particularly relevant in steam turbine bearing housings where probe body temperatures can approach 150 °C during sustained full-load operation.

Target Material Sensitivity: The eddy-current field penetration depth (skin depth) is a function of target conductivity and permeability. For AISI 4140 steel at 1 MHz excitation, skin depth is approximately 8 µm — well within the surface layer of a machined journal. This shallow penetration means the probe responds to surface geometry and conductivity, not bulk material properties, making it insensitive to subsurface defects but highly sensitive to surface finish variations. OEM specifications typically require a target surface roughness of Ra ≤ 0.8 µm within the probe sensing zone.

Redundancy Architecture: In API 670-compliant installations, proximity probes are typically deployed in pairs (X–Y configuration, 90° apart) at each bearing plane. The 330905-00-07-10-02-05 supports this architecture directly. Each probe feeds an independent Proximitor® channel, and the 3500 Series monitor performs vector summation of the two orthogonal displacement signals to compute orbit plots and 1X/2X vibration vectors — enabling precise identification of unbalance, misalignment, and fluid-film instability without removing the machine from service.

System Integration Benefits

• Zero-Wear Sensing: Non-contact measurement eliminates mechanical contact between sensor and rotating shaft. There is no wear mechanism, no friction-induced heat, and no periodic replacement interval driven by sensor degradation — only environmental factors (temperature, chemical exposure) govern service life.
• Deterministic Signal Latency: The eddy-current measurement chain introduces less than 1 ms of signal latency from physical gap change to analog output voltage change. This deterministic response time is essential for machinery protection systems that must trip within defined time windows (typically <100 ms from alarm threshold crossing to relay actuation).
• Direct Drop-In Replacement: The 330905-00-07-10-02-05 is dimensionally and electrically identical to the original OEM specification. Replacement requires no Proximitor® recalibration, no software parameter changes in the 3500 monitor, and no modification to existing probe mounting hardware — minimizing planned outage duration.
• Broad Frequency Bandwidth: The probe and Proximitor® system maintains flat frequency response from DC (static position) to beyond 10 kHz, covering the full spectrum of turbomachinery vibration phenomena: synchronous (1X), subsynchronous (oil whirl at 0.43–0.48X), supersynchronous (blade-pass, gear mesh), and structural resonances.
• Orbit Plot Capability: Paired X–Y probe installations generate shaft orbit data that allows engineers to distinguish between unbalance (circular orbit), misalignment (figure-eight orbit), and fluid-film instability (precessing orbit) — diagnostic information that accelerometers mounted on bearing housings cannot provide.
• Hazardous Area Compatibility: When assembled with a certified Zener barrier or galvanic isolator, the complete measurement chain achieves ATEX Zone 0/1 and IECEx certification, permitting installation in gas-group IIC environments (hydrogen service) without additional enclosure requirements.
• Long Extension Cable Support: The probe is designed to operate with Bently Nevada 330130-series extension cables up to 9 metres, allowing the Proximitor® to be located outside high-temperature zones while the probe remains at the bearing. Total system cable length (integral + extension) must remain within the matched calibration specification.
• Integration with 3500 Machinery Protection System: Output from the Proximitor® feeds directly into 3500/40M or 3500/42M monitor cards, which provide configurable alarm and danger setpoints, gap voltage monitoring, OK relay outputs, and Modbus/PROFIBUS communication to plant DCS — delivering full diagnostic transparency without additional signal conditioning hardware.

Quality Assurance & Global Logistics

Every unit of the 330905-00-07-10-02-05 offered through siemensplc.com is sourced from verified supply channels with full part number and lot traceability. Prior to dispatch, each probe undergoes physical inspection covering connector integrity, cable jacket condition, probe tip geometry, and label verification against the declared part number. A certificate of conformance and itemized packing list accompany every shipment.

Packaging follows anti-static and moisture-barrier protocols appropriate for precision sensing elements: foam-lined inner packaging, sealed moisture barrier bag with desiccant, and rigid outer carton rated for international air freight handling. This packaging specification protects the coil assembly and connector from electrostatic discharge and humidity ingress during transit.

Shipments originate from Xiamen, China — a major export hub with direct access to DHL, FedEx, and UPS Express international networks. Standard express delivery reaches most destinations in Southeast Asia, the Middle East, Europe, and the Americas within 3–7 business days. For plant turnaround scenarios with compressed timelines, same-day dispatch on confirmed orders placed before 14:00 CST is available. Full export documentation — commercial invoice, packing list, and certificate of origin — is prepared for every international shipment to facilitate customs clearance without delay.

All products carry a 12-month warranty from the date of shipment, covering manufacturing defects and verified non-conformance to published Bently Nevada specifications. Technical support from our engineering team is available throughout the warranty period and beyond.

Contact Information

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