Bently Nevada 330904-09-17-05-01-05 Proximity Probe – 3300 NSv Series

Bently Nevada 330904-09-17-05-01-05 — 8mm Eddy Current Proximity Probe for Critical Rotating Machinery Protection

The Bently Nevada 330904-09-17-05-01-05 is a factory-original, 8mm-diameter eddy current proximity probe belonging to the 3300 NSv (Non-contacting Vibration) platform. Within a continuous machinery protection loop, this probe functions as the primary transduction element: it converts the physical gap between its tip and a conductive target surface into a calibrated DC voltage signal, which downstream monitors interpret as shaft radial displacement, axial thrust position, or differential expansion. The probe operates without mechanical contact, eliminating wear-induced drift and enabling indefinite service life under normal process conditions.

In a typical API 670-compliant installation, the 330904-09-17-05-01-05 is mounted in a radial or axial bracket at a nominal gap of 1.0 mm from the shaft journal. The integral coaxial cable carries the high-frequency oscillator signal to a matched 3300 XL 8mm Proximitor Sensor, which demodulates the eddy-current loading into a –10.0 VDC analog output at the calibrated gap. This output feeds directly into Bently Nevada 3500 Series rack monitors, third-party DCS analog input cards, or safety instrumented system (SIS) voting logic without additional signal conditioning. The result is a deterministic, low-latency measurement chain with a frequency response flat from DC to 10,000 Hz — sufficient to resolve sub-synchronous instabilities, oil-whirl events, and blade-pass excitations in high-speed turbomachinery.

The probe’s 0.9 m integral armored cable and 5.0 m extension cable configuration (suffix -09-17-05) covers the majority of standard bearing-housing-to-junction-box routing distances in gas turbines, steam turbines, centrifugal compressors, and large motor-driven pump trains. The stainless steel hermetic housing maintains IP67 integrity against process fluid splash, steam condensate, and aggressive cleaning agents encountered in petrochemical and power-generation environments.

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Technical Parameters

Hardware Logical Analysis

The 330904-09-17-05-01-05 implements a passive LC-tank eddy current topology. The probe coil, wound on a ferrite former inside the stainless steel tip, forms the inductive element of an oscillator circuit resident in the Proximitor. When the probe tip approaches a conductive target, eddy currents induced in the target surface load the coil, reducing the oscillator’s Q-factor and lowering the oscillation amplitude. The Proximitor’s demodulator converts this amplitude change into a linear DC voltage with the calibrated scale factor of 7.87 V/mm. Because the oscillator frequency (nominally 1.0 MHz for the 8mm probe) is set by the matched probe-cable-proximitor system, substituting any single component from a different calibration family will shift the scale factor and invalidate the system calibration — a critical procurement consideration.

EMC Design: The integral armored cable uses a double-braid shield terminated at both the probe body and the Proximitor input connector. This construction attenuates common-mode interference from adjacent power cables and variable-frequency drives (VFDs) operating in the 2–20 kHz switching range. The shield drain wire is grounded at the Proximitor end only, preventing ground-loop currents from appearing as low-frequency noise on the measurement signal. In installations where VFD-induced interference exceeds 50 mV peak-to-peak on the raw signal, Bently Nevada recommends routing the probe cable in a dedicated metallic conduit separated by a minimum of 150 mm from power conductors — a practice this probe’s armored construction directly supports.

Thermal Stability Architecture: The ferrite core material is selected for a low temperature coefficient of permeability across the –35°C to +177°C operating band. Combined with the Proximitor’s internal temperature compensation circuit, the system maintains scale factor accuracy within ±1% of nominal across the full thermal range. This is particularly significant in steam turbine applications where bearing housing temperatures can cycle between ambient and 150°C during start-stop sequences, and where a thermally unstable probe would introduce false thrust-position readings that could trigger spurious shutdowns.

Hermetic Sealing: The probe tip and cable entry are sealed with a glass-to-metal hermetic feedthrough, not an elastomeric O-ring. This construction eliminates the permeation path for hydrogen sulfide (H₂S) and other aggressive process gases present in sour-gas compressor environments, where O-ring-sealed probes have historically exhibited accelerated degradation of the internal coil assembly.

System Integration Benefits

• Direct API 670 Compliance: The probe meets 5th Edition requirements for radial vibration and axial position transducers without field modification, simplifying third-party audits and insurance underwriting for critical machinery trains.
• Zero Recalibration on Replacement: Because the scale factor is determined by the matched probe-cable-proximitor system, replacing a failed probe with an identical 330904-09-17-05-01-05 and resetting the installation gap to 1.0 mm restores the calibrated measurement chain without requiring Proximitor recalibration or monitor rescaling.
• Deterministic DC-to-10 kHz Bandwidth: The flat frequency response from DC eliminates the phase lag introduced by AC-coupled sensors, preserving the time-domain integrity of slow-roll runout vectors and static eccentricity measurements used in rotor balancing.
• Sub-25 mV Noise Floor: The low broadband noise floor allows the monitor’s alarm thresholds to be set closer to the actual vibration baseline, improving early-warning sensitivity for incipient bearing defects without increasing nuisance-trip rates.
• Broad Target Material Compatibility: While optimized for AISI 4140 steel, the probe can be factory-characterized for alternative shaft alloys (Inconel 718, titanium) by specifying the target material at order time, enabling use in aerospace-derivative gas turbines and cryogenic expanders.
• IP67 Ingress Protection: The hermetically sealed housing allows the probe to remain installed during water-wash cleaning cycles and steam purging of bearing housings, eliminating the downtime associated with probe removal and reinstallation.
• ATEX Zone Compatibility: The probe’s ATEX certification permits installation in Zone 1 and Zone 2 hazardous areas (gas group IIC, temperature class T4) without additional intrinsic safety barriers on the probe side, reducing panel wiring complexity.
• Plug-and-Play with 3500 Series Monitors: The –10.0 VDC output at nominal gap is within the input range of all Bently Nevada 3500 Series monitor cards (3500/40M, 3500/42M, 3500/45) and requires no jumper changes or software rescaling when installed as a direct replacement.

Quality Assurance & Global Logistics

Every Bently Nevada 330904-09-17-05-01-05 unit supplied by siemensplc.com is sourced through verified distribution channels and subjected to a structured incoming inspection protocol before dispatch. Inspection steps include visual examination of the probe tip and cable armor for mechanical damage, connector pin integrity verification, coaxial cable impedance measurement (nominal 50 Ω ± 5%), and functional oscillation check with a reference Proximitor to confirm the output voltage at a known gap. Units that do not pass all inspection criteria are quarantined and not offered for sale.

Shipments originate from our warehouse in Xiamen, China — a major international logistics hub with direct access to DHL Express, FedEx International Priority, UPS Worldwide Express, and SF International freight services. Standard export documentation includes a commercial invoice, packing list, and certificate of conformance (CoC). For projects requiring additional documentation — such as material test reports (MTR), ATEX declaration of conformity, or third-party NIST-traceable calibration certificates — these can be arranged at the time of order. Typical transit times are 3–5 business days to Europe and North America, and 2–4 business days to Southeast Asia and the Middle East. All shipments are fully insured and tracked from dispatch to delivery confirmation.

Our 12-month warranty covers manufacturing defects and calibration drift beyond the specified ±1% tolerance. Warranty claims are processed with a replacement-first policy: a replacement unit is dispatched upon receipt of the failed unit and completion of a brief failure analysis form, minimizing plant downtime.

Contact Information

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