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

Bently Nevada 330905-00-05-10-02-05: Eddy-Current Proximity Probe for Shaft Displacement and Vibration Measurement in Rotating Machinery

The 330905-00-05-10-02-05 is a 5 mm eddy-current proximity probe from Bently Nevada’s 3300 NSv (Non-contacting vibration) Series. Its function within a rotating machinery protection loop is unambiguous: it converts the physical gap between the probe tip and a conductive target shaft into a proportional DC voltage signal, which the downstream driver/oscillator-demodulator then conditions into a calibrated output readable by the monitoring rack. This non-contact measurement principle eliminates mechanical wear entirely, making the probe suitable for continuous, uninterrupted operation across the full service life of the host machine — typically measured in decades rather than years.

In a turbomachinery protection architecture, the proximity probe occupies the first node in the measurement chain. Its output feeds the 3300 XL driver (330180 Series), which supplies the probe with a 1 MHz oscillator signal and demodulates the impedance change caused by eddy-current induction in the target material. The resulting voltage slope — nominally –7.87 V/mm for the 3300 NSv system — is linear across the calibrated gap range of 0.25 mm to 2.25 mm. Any deviation from this linearity, whether caused by shaft runout, thermal expansion, or bearing wear, is captured with sub-micron resolution and transmitted to the 3500 Series monitoring rack for alarm and trip processing. This deterministic signal path, from mechanical displacement to relay output, is what makes the 3300 NSv probe a load-bearing element in API 670-compliant machinery protection systems.

The 330905-00-05-10-02-05 variant is defined by its 5 mm probe tip diameter and 1.0 m integral cable, making it the standard configuration for installations where radial clearance around the shaft journal is constrained. The compact tip geometry allows mounting in bearing housings and seal cavities where 8 mm probes cannot be accommodated without machining modifications. The integral cable terminates in a standard Bently Nevada coaxial connector, mating directly with 330130 Series extension cables without adapters or impedance mismatches.

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Technical Parameters

Hardware Logical Analysis

The eddy-current operating principle of the 330905-00-05-10-02-05 relies on the interaction between a high-frequency electromagnetic field generated at the probe tip coil and the conductive target surface. When the 330180 driver applies a 1 MHz sinusoidal excitation to the probe coil, the field penetrates the target material to a skin depth determined by the target’s electrical conductivity and magnetic permeability. Eddy currents induced in the target create a counter-magnetic field that loads the probe coil, altering its impedance. The driver’s demodulation circuit measures this impedance change and converts it to a proportional DC voltage output.

The 5 mm tip geometry of this variant concentrates the electromagnetic field into a tighter focal zone compared to 8 mm probes, which reduces the effective sensing area but improves spatial resolution for small-diameter shafts (typically below 75 mm journal diameter). The trade-off is a marginally reduced signal-to-noise ratio at the extremes of the calibrated gap range, which the 3300 XL driver compensates through its internal gain-trimming circuitry.

EMC performance is achieved through the coaxial cable construction: the signal conductor is shielded by a continuous braid that is grounded at the driver end only, preventing ground loop formation. The probe body is constructed from 316 stainless steel, which provides both corrosion resistance in wet or chemically aggressive environments and magnetic neutrality — the housing material does not contribute to the eddy-current field, ensuring that only the target gap determines the output voltage. The integral cable jacket is rated for continuous exposure to lubricating oils, hydraulic fluids, and steam condensate, which are the dominant contaminants in turbine bearing housings.

The 1.0 m integral cable length of this variant is matched to the 330130 Series extension cable system. The total probe-plus-extension cable length must remain within the calibrated range for the selected driver module; exceeding this length introduces distributed capacitance that shifts the oscillator frequency and degrades scale factor accuracy. For installations requiring cable runs beyond 9 m, Bently Nevada specifies the use of a dedicated long-cable driver variant — a constraint that must be verified during system design.

System Integration Benefits

• Direct API 670 compliance: The 330905-00-05-10-02-05 forms part of a measurement chain that meets API 670 (5th Edition) requirements for radial vibration and axial position monitoring, eliminating the need for additional compliance engineering when specifying new machinery protection systems.
• Zero-recalibration replacement: As a form-fit-function equivalent within the 3300 NSv series, this probe replaces worn or damaged units without requiring re-ranging or re-scaling of the 3500 Series monitoring rack, reducing planned maintenance downtime to the time required for physical probe swap and gap verification.
• Deterministic signal latency: The analog voltage output of the probe-driver chain introduces no digital processing delay. The 3500 Series rack receives a continuous, real-time signal that is processed within the rack’s 20 ms voting cycle, ensuring that trip relay activation occurs within one voting period of a threshold exceedance.
• Dual-measurement capability: A single probe installation can simultaneously provide radial vibration (AC component) and average shaft centerline position (DC component) data to the monitoring rack, reducing the number of penetrations required in the bearing housing and simplifying installation in space-constrained machinery.
• Hazardous area deployment: ATEX/IECEx Zone 1 certification allows installation in explosive atmospheres without additional intrinsic safety barriers, provided the associated driver module carries equivalent certification — a common configuration in offshore and refinery applications.
• Broad target material compatibility: While optimized for AISI 4140 steel, the probe operates with acceptable linearity on other ferromagnetic alloys including 17-4 PH stainless steel and Inconel 718, covering the shaft materials used in most high-temperature turbine applications.
• Diagnostic transparency: The 3500 Series rack’s OK relay monitors the probe-driver output voltage continuously. A probe cable fault, connector failure, or gap exceedance beyond the calibrated range drives the output outside the –2 V to –18 V OK window, triggering an immediate NOT OK condition that is distinguishable from a process alarm — preventing false machinery trips while ensuring sensor faults are never masked.
• Scalable system architecture: The 3300 NSv probe is compatible with both the legacy 3300 XL rack and the current 3500 Series platform, allowing phased system upgrades where probes are retained while monitoring electronics are modernized — protecting the capital investment in installed sensor infrastructure.

Quality Assurance & Global Logistics

Every 330905-00-05-10-02-05 unit supplied by siemensplc.com is sourced from verified distribution channels with full traceability to Bently Nevada (Baker Hughes) manufacturing records. Pre-shipment inspection covers connector integrity, cable continuity, probe body condition, and packaging seal verification. A certificate of conformance and the original manufacturer datasheet accompany each shipment.

Packaging follows ESD-safe protocols: the probe is sealed in an anti-static bag, cushioned in closed-cell foam, and enclosed in a double-wall corrugated carton rated for international air freight handling. From our warehouse in Xiamen, China, shipments are dispatched via DHL Express, FedEx International Priority, or UPS Worldwide Expedited, with full tracking provided at the time of dispatch. Standard transit times to major industrial hubs are 3–5 business days to Europe, 2–4 business days to Southeast Asia, and 4–7 business days to North America and the Middle East. Export documentation — including commercial invoice, packing list, and certificate of origin — is prepared in compliance with destination country customs requirements. HS Code 9031.80 applies to this product category for customs classification purposes.

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 dispatch or credit note issued upon confirmation of the defect.

Contact Information

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