Bently Nevada 330904-00-17-05-01-00 Proximity Transducer – 3300 XL NSv

Bently Nevada 330904-00-17-05-01-00: Eddy-Current Displacement Sensing in API 670 Turbomachinery Protection Loops

The 330904-00-17-05-01-00 is a factory-calibrated, non-contact eddy-current proximity transducer within Bently Nevada’s 3300 XL NSv Proximity Transducer System. It functions as the primary sensing element in continuous shaft radial vibration, axial position, and differential expansion measurement loops on rotating machinery governed by API 670 fourth and fifth edition requirements. The probe assembly — a 5 mm tip-diameter stainless-steel probe body, a 17-inch (432 mm) armored extension cable, and a 5-meter (5 m) interconnect cable — is shipped as a pre-matched, pre-calibrated set. Field substitution of individual sub-components without system recalibration is not permitted under the 3300 XL NSv architecture, because the sensitivity scale factor (nominally 7.87 V/mm or 200 mV/mil) is derived from the combined electromagnetic characteristics of the probe coil, extension cable impedance, and the paired Proximitor® sensor driver circuit.

In a typical turbomachinery protection loop, this transducer is mounted in a radial plane at 90° X–Y orientation relative to the shaft centerline, or axially against a thrust collar for position measurement. The Proximitor® sensor — powered at –24 VDC — drives a 1 MHz oscillator signal through the extension cable to the probe coil. When a conductive target (shaft) enters the probe’s electromagnetic field, eddy currents are induced on the target surface, loading the oscillator circuit and producing a proportional DC voltage output. The 330904-00-17-05-01-00 delivers a linear output range of approximately –2 VDC to –18 VDC across a gap range of 0.25 mm to 2.25 mm (10 mil to 90 mil), with a nominal gap setpoint of 1.0 mm to 1.5 mm (40 mil to 60 mil) for most turbomachinery applications. This output feeds directly into Bently Nevada 3300 series rack monitors or third-party DCS/SIS analog input cards with compatible input impedance (≥10 kΩ).

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Technical Parameters

Hardware Logical Analysis

The 3300 XL NSv system employs a three-component matched-set architecture: probe, extension cable, and Proximitor® sensor. The 330904-00-17-05-01-00 probe coil is wound to a precise inductance value that, when combined with the 17-inch extension cable’s distributed capacitance and resistance, presents a defined load to the Proximitor® oscillator. Any deviation in cable length or coil geometry shifts the resonant frequency of the LC tank circuit, directly altering the sensitivity scale factor. This is why Bently Nevada specifies that all three components must be replaced as a matched set — a design constraint that eliminates field-calibration ambiguity and ensures measurement traceability.

The probe tip geometry — 5 mm diameter — is optimized for shaft diameters commonly encountered in steam turbines, gas turbines, and centrifugal compressors (typically 50 mm to 300 mm shaft OD). The smaller tip diameter, compared to the 8 mm variant, provides a tighter electromagnetic field focus, reducing sensitivity to surface irregularities such as residual magnetism, chrome plating, or surface roughness variations on the target shaft. The armored extension cable uses a double-shielded coaxial construction with a stainless-steel braid outer armor, providing mechanical protection against abrasion and crush loads in confined bearing housing environments while maintaining the cable’s characteristic impedance within the ±2% tolerance required for calibrated system accuracy.

EMC performance is addressed at the probe level through the coaxial cable’s continuous shield, which is grounded at the Proximitor® sensor end only (single-point grounding), preventing ground loop currents that would appear as low-frequency noise on the output signal. The 1 MHz carrier frequency is well above the industrial noise band (50/60 Hz and harmonics up to ~10 kHz), and the Proximitor® demodulation circuit uses synchronous detection referenced to the oscillator, providing inherent rejection of out-of-band interference. This architecture allows the system to maintain a signal-to-noise ratio sufficient to resolve shaft vibration amplitudes as small as 2.5 µm (0.1 mil) in the presence of strong electromagnetic fields from adjacent motor drives or transformer banks.

System Integration Benefits

• Direct API 670 Compliance: The 330904-00-17-05-01-00 satisfies API 670 fifth edition requirements for non-contact vibration transducer systems without additional field calibration, reducing commissioning time on new installations and replacement projects.
• Deterministic Output Latency: The analog –24 VDC output signal propagates from probe to monitor with a group delay determined solely by cable capacitance (typically <1 µs for 5 m interconnect), ensuring that vibration events are captured with no software-induced latency — a critical requirement for machinery protection systems with trip response times of 20 ms or less.
• Backward Compatibility with 3300 Series Monitors: The NSv system’s output characteristics are electrically identical to the standard 3300 XL system, allowing direct substitution into existing 3300/16, 3300/20, 3300/25, and 3300/55 monitor channels without reconfiguration of monitor alarm or trip setpoints.
• Diagnostic Transparency via Gap Voltage: The DC bias voltage at the monitor’s gap output channel provides a continuous, real-time indication of probe-to-shaft gap. Trending this value over time allows maintenance engineers to detect bearing wear (decreasing gap) or shaft bow (oscillating gap at 1× running speed) before vibration amplitude thresholds are reached.
• Compatibility with System 1® Software: When connected to a Bently Nevada 3500 or 3300 series monitor networked to System 1® condition monitoring software, the transducer’s output supports full waveform capture, orbit plot generation, and spectral analysis — enabling root-cause diagnostics without additional instrumentation.
• Minimal Installation Footprint: The 5 mm probe body threads into standard M8×1.0 or 1/4–28 UNF probe holders, compatible with the majority of existing turbomachinery bearing housing probe ports, eliminating the need for housing modification during replacement.
• Resistance to Process Fluid Contamination: The IP67-rated probe body and sealed extension cable connector resist ingress of lubricating oil, seal gas condensate, and water — common contaminants in bearing housing environments — maintaining measurement integrity without periodic cleaning or resealing.
• Scalable to Redundant Protection Architectures: In 2oo3 (two-out-of-three) voting protection loops, three 330904-00-17-05-01-00 transducers can be installed at 120° intervals around the shaft, with each feeding an independent monitor channel. The matched sensitivity of factory-calibrated sets ensures that all three channels produce consistent readings, preventing spurious trips caused by transducer-to-transducer sensitivity mismatch.

Quality Assurance & Global Logistics

Every 330904-00-17-05-01-00 unit supplied by siemensplc.com is sourced through verified Bently Nevada (Baker Hughes) authorized distribution channels or directly from OEM-certified surplus inventory. Each assembly undergoes a pre-shipment inspection protocol that includes visual examination of the probe tip for mechanical damage, continuity and insulation resistance testing of the extension and interconnect cables, and verification of the factory calibration certificate against the unit’s serial number. Units that do not carry traceable documentation are not offered for sale.

Shipments originate from our warehouse in Xiamen, China — a major international logistics hub with direct access to Xiamen Gaoqi International Airport (XMN) and Xiamen Port, supporting both air freight and sea freight consolidation. Standard export documentation — commercial invoice, packing list, certificate of origin, and MSDS where applicable — is prepared for all international orders. Air freight to major industrial hubs in Southeast Asia, the Middle East, Europe, and North America typically achieves transit times of 3 to 7 business days. For urgent machinery-down situations, same-day dispatch on in-stock units is available upon order confirmation before 14:00 CST. All units are packed in anti-static, shock-absorbing foam inserts within double-wall corrugated cartons, with individual part labeling to facilitate receiving inspection at the destination facility.

Contact Information

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