Bently Nevada 330101-00-28-20-02-05 Proximity Transducer – 3300 XL Series

Bently Nevada 330101-00-28-20-02-05 – 8mm Eddy-Current Proximity Transducer in the 3300 XL Monitoring Architecture

The Bently Nevada 330101-00-28-20-02-05 is an 8 mm diameter eddy-current proximity transducer belonging to the 3300 XL Series — a platform engineered specifically for continuous, non-contact measurement of shaft radial vibration, axial position, and differential expansion in rotating machinery. Within a complete 3300 XL measurement chain, this probe functions as the primary sensing element: it generates a high-frequency oscillating electromagnetic field (nominally 1.0 MHz) that induces eddy currents in the conductive target surface. The resulting impedance change is converted by the paired Proximitor® sensor into a DC-proportional voltage output, delivering a linear displacement signal with a sensitivity of 7.87 V/mm (200 mV/mil) across a calibrated gap range of 0.25 mm to 2.54 mm (10 mil to 100 mil).

The part number suffix encodes the full mechanical configuration: 00 (standard probe body), 28 (28 mm active probe length), 20 (2.0 m integral cable), 02 (standard connector), 05 (stainless steel armored cable jacket). This specific combination is widely deployed in steam turbine bearing housings, centrifugal compressor radial bearing planes, and boiler feed pump shaft monitoring loops where cable routing through high-temperature or mechanically abrasive environments demands armored protection without sacrificing signal fidelity.

Unlike capacitive or optical displacement sensors, the eddy-current principle is immune to contamination from oil mist, condensate, and particulate matter — conditions endemic to turbomachinery bearing chambers. The probe tip operates reliably at continuous temperatures up to 177°C, making it suitable for direct installation adjacent to journal bearings in gas turbines and steam turbines without thermal derating.

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Technical Parameters

Hardware Logical Analysis

The 330101-00-28-20-02-05 probe coil is wound on a ferrite-loaded bobbin and encapsulated in a PEEK (polyether ether ketone) tip housing. PEEK provides a dielectric constant stable across the full operating temperature range, preventing thermally induced drift in the coil’s self-inductance — a failure mode that degrades scale factor linearity in probes using lower-grade thermoplastics. The coil assembly is hermetically sealed against the integral cable entry point with an epoxy compound rated to MIL-I-16923, eliminating moisture ingress paths that would otherwise shift the oscillator’s resonant frequency and corrupt the displacement-to-voltage transfer function.

The stainless steel armor (suffix -05) is a 304 SS interlocked spiral wrap over the coaxial signal cable. This construction provides three simultaneous functions: mechanical protection against abrasion and crush loads during installation through conduit or cable trays; a degree of EMI shielding supplementary to the coaxial braid; and a defined bend radius constraint that prevents coil deformation from cable pull forces. The coaxial cable itself maintains a controlled 50 Ω characteristic impedance to the Proximitor® input, ensuring that the high-frequency oscillator signal (1 MHz) is not attenuated or reflected by impedance discontinuities over the 2.0 m cable run.

From an EMC standpoint, the 3300 XL probe system is designed to reject common-mode interference. The Proximitor® sensor’s differential input architecture rejects noise coupled equally onto the signal and shield conductors — a critical property in switchgear rooms and motor control centers where 50/60 Hz and VFD-generated harmonics can reach several volts of common-mode amplitude. The probe’s integral cable shield is grounded at the Proximitor® end only (single-point grounding), preventing ground-loop currents that would appear as low-frequency noise on the displacement output.

The 28 mm active probe length (suffix -28) determines the depth of the electromagnetic field penetration and, consequently, the probe’s sensitivity to target surface geometry variations. A longer active element increases the effective sensing area, improving signal-to-noise ratio on rough or lightly oxidized shaft surfaces, while the 8 mm body diameter constrains the installation envelope to standard bearing housing probe ports — typically M10 × 1.0 or 3/8-24 UNF threaded bosses per API 670 Table 1 requirements.

System Integration Benefits

• API 670 Fifth Edition Compliance: The 330101-00-28-20-02-05 is dimensioned and calibrated to satisfy API 670 radial vibration measurement requirements, enabling direct use in machinery protection systems for new installations and retrofits without additional engineering deviation documentation.
• Deterministic Signal Latency: The eddy-current measurement chain introduces no sampling delay — the Proximitor® output is a continuous analog voltage. When interfaced to a 3300/16 or 3300/20 monitor module, the overall system response time is governed by the monitor’s configurable integration time constant (typically 1 ms to 100 ms), not by probe electronics, preserving deterministic alarm response.
• Direct Drop-In Replacement: The 330101-00-28-20-02-05 is dimensionally and electrically interchangeable with earlier 330101 series probes. No recalibration of the Proximitor® or monitor module is required when replacing a like-for-like unit, minimizing planned maintenance downtime windows.
• Diagnostic Transparency via Gap Voltage: The –24 VDC bias output provides a continuous, measurable indicator of probe-to-shaft gap. Maintenance personnel can verify correct installation gap (typically –10 V to –12 V at 1.0 mm nominal gap) with a standard voltmeter, without requiring specialized calibration equipment or system shutdown.
• Broad Target Material Compatibility: While factory-calibrated for AISI 4140 steel, the probe can be field-calibrated for alternative shaft materials (stainless steel, titanium, Inconel) using Bently Nevada’s published correction factors, extending applicability across diverse turbomachinery metallurgies.
• Redundant Monitoring Architecture Support: Two 330101-00-28-20-02-05 probes installed at 90° (X–Y configuration) per API 670 Section 5.3 provide full orbital trajectory data for shaft centerline analysis. The probe’s consistent sensitivity tolerance (±1% of scale factor) ensures that X and Y channel outputs are directly comparable without channel-specific gain correction in the monitor.
• High-Temperature Margin for Bearing Proximity: With a probe tip rating of 177°C, the unit operates with a 30–50°C thermal margin above typical journal bearing housing temperatures (120–140°C), preventing thermally induced sensitivity drift during load transients or cooling system upsets.
• Minimal Maintenance Footprint: The non-contact measurement principle eliminates mechanical wear. Mean time between replacement (MTBR) for properly installed 3300 XL probes in clean bearing environments exceeds 10 years, reducing lifecycle maintenance cost compared to contact-type displacement sensors.

Quality Assurance & Global Logistics

Every 330101-00-28-20-02-05 unit supplied by siemensplc.com is sourced through verified industrial procurement channels and subjected to a structured pre-shipment inspection protocol. Physical verification covers label integrity (part number, date code, serial number cross-referenced against Bently Nevada’s published format), connector condition (coaxial center pin concentricity, thread engagement), cable armor continuity, and tip housing surface condition. Electrical verification includes DC resistance measurement of the probe coil (nominal 4–6 Ω) and insulation resistance between the coaxial shield and armor (>100 MΩ at 500 VDC), confirming the hermetic seal integrity of the cable entry epoxy.

Shipments originate from our Xiamen, China operations hub. Standard export documentation — commercial invoice, packing list, and certificate of origin — is provided with every order. For projects requiring additional documentation (material test reports, calibration certificates, or certificates of conformance), these are specified at the time of RFQ. Packaging uses anti-static foam-lined cartons with moisture-barrier inner bags and desiccant packs, conforming to ASTM D4169 Distribution Cycle A for air freight. Typical dispatch lead time for in-stock units is 1–3 business days. International express delivery via DHL, FedEx, or UPS reaches most destinations within 3–7 business days. Sea freight consolidation is available for bulk orders of 10+ units.

Contact Information

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