Bently Nevada 330103-20-25-05-02-CN Proximity Transducer – 3300 XL Series

Bently Nevada 330103-20-25-05-02-CN: 8mm Eddy-Current Proximity Transducer System for Critical Rotating Machinery Protection

The 330103-20-25-05-02-CN is a three-component proximity transducer system from Bently Nevada’s 3300 XL 8mm Series, designed for continuous, non-contact measurement of radial shaft vibration and axial position on turbomachinery, compressors, and other critical rotating assets. The system comprises a probe body (8 mm tip diameter, 20 mm body length), a 2.5 m extension cable, and a 3300 XL 8mm Proximitor® driver — all factory-matched and calibrated as a single interchangeable assembly. The CN suffix designates the connector configuration optimized for Chinese domestic installation standards, ensuring mechanical compatibility with locally sourced junction boxes and conduit fittings without field modification.

In a typical machinery protection loop, the Proximitor driver generates a 1 MHz oscillator signal that is transmitted through the extension cable to the probe coil. When the conductive shaft surface enters the probe’s electromagnetic field, eddy currents are induced, loading the oscillator and producing a DC output voltage proportional to the gap distance. The 330103-20-25-05-02-CN delivers a calibrated sensitivity of 7.87 V/mm (200 mV/mil) across a linear range of 0.25 mm to 2.26 mm, with a flat frequency response from DC to 10,000 Hz — sufficient to resolve sub-synchronous instabilities, oil whirl, and blade-pass frequencies in most industrial turbomachinery applications.

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Technical Parameters

Hardware Logical Analysis

The 3300 XL architecture separates the oscillator/demodulator electronics from the probe body, placing the active Proximitor driver at a thermally stable location away from the machine casing. This topology has two direct engineering consequences: first, the probe body itself contains no active components, making it inherently immune to high-temperature derating that would otherwise compress the linear range; second, the matched cable pair acts as a transmission line with defined characteristic impedance, and Bently Nevada’s factory calibration accounts for the cable’s distributed capacitance so that the end-to-end sensitivity remains within ±0.254 V/mm of the nominal 7.87 V/mm specification without field trimming.

The 8 mm probe diameter is a deliberate mechanical trade-off. Larger coil diameter increases the electromagnetic field depth and improves signal-to-noise ratio on shafts with surface finish Ra > 1.6 µm, while remaining compact enough for installation in bearing housings with limited radial clearance — typically 25 mm to 35 mm boss diameter. The probe body’s stainless steel housing provides a Faraday shield that attenuates capacitively coupled interference from adjacent high-voltage cables, contributing to the system’s compliance with IEC 61000-4-3 radiated immunity requirements at 10 V/m field strength.

The Proximitor driver’s internal AGC (Automatic Gain Control) loop maintains oscillator amplitude stability across supply voltage variations of ±10% from nominal −24 VDC. This means that transient voltage dips caused by relay switching events on shared DC bus segments do not produce false vibration spikes at the monitor input — a failure mode that has caused spurious machinery trips in installations using non-AGC proximity systems. The driver’s output impedance is specified at <100 Ω, compatible with the input impedance of Bently Nevada 3300 and 3500 series monitor cards as well as third-party 4–20 mA signal conditioners.

EMC design within the Proximitor enclosure includes a multi-layer PCB ground plane, ferrite bead filtering on the supply rail, and a shielded output connector. These measures collectively suppress conducted emissions below the CISPR 11 Class A limit, allowing the driver to be mounted in mixed-signal cabinets alongside PLC I/O modules without cross-talk penalties.

System Integration Benefits

• Direct monitor compatibility: The 330103-20-25-05-02-CN is a certified drop-in replacement for existing 3300 XL 8mm installations on Bently Nevada 3300/16, 3500, and 3701 monitor racks — no span or zero recalibration required at the monitor card level, reducing planned maintenance downtime to the time required for mechanical probe swap only.
• Deterministic analog output: The DC-to-10 kHz flat frequency response ensures that the monitor’s DSP receives an undistorted time-domain waveform, preserving the phase relationships needed for orbit plot construction and 1X/2X vector analysis in System 1 software.
• Diagnostic transparency via gap voltage: The DC component of the output voltage provides a continuous, real-time indication of the average shaft centerline position. Operators can trend this value to detect bearing wear, thermal growth, and alignment shift without interrupting production — a capability that purely AC-coupled sensors cannot provide.
• Hazardous area deployment: ATEX and FM system-level approvals allow installation in Zone 1/Division 1 classified areas (gas groups IIC/IIB) when used with the specified Proximitor driver and associated apparatus, eliminating the need for separate intrinsic safety barriers in most petrochemical applications.
• Reduced spare-parts complexity: The matched-pair assembly concept means that a single part number covers probe, cable, and driver as a calibrated unit. Maintenance planners can stock one SKU instead of three separate line items, simplifying BOM management and reducing the risk of mismatched component combinations that degrade sensitivity accuracy.
• PLC/DCS analog input compatibility: The −1 VDC to −17 VDC output maps directly to the input range of standard ±10 V differential analog input modules on Siemens S7-300/400/1500, Rockwell ControlLogix, Honeywell C300, and ABB AC800M platforms after simple scaling in the AI channel configuration — no signal conditioning hardware required.
• Predictive maintenance data density: At 10,000 Hz bandwidth, the transducer resolves vibration components up to the 10th harmonic of a 1,000 RPM machine or the 3rd harmonic of a 3,000 RPM machine, providing sufficient spectral resolution for early-stage fault detection in blade, vane, and gear-mesh frequencies without waveform aliasing.
• Long-term calibration stability: The eddy-current sensing principle is insensitive to contamination by oil mist, water ingress, and process gas condensate — common environmental conditions in turbomachinery bearing housings — maintaining calibration accuracy over multi-year service intervals between scheduled calibration checks.

Quality Assurance & Global Logistics

Every 330103-20-25-05-02-CN unit supplied by siemensplc.com is sourced through verified industrial supply channels and undergoes a structured pre-shipment inspection covering label integrity, housing markings, serial number traceability, and connector condition. Units are stored in a climate-controlled warehouse in Xiamen, China, in anti-static packaging to prevent electrostatic discharge damage to the Proximitor driver’s CMOS oscillator circuitry during storage and transit.

Bently Nevada manufactures the 3300 XL series under Baker Hughes’ ISO 9001-certified quality management system. The 330103 probe series has an established field history exceeding two decades in power generation, oil & gas, and petrochemical applications globally, with documented MTBF data supporting multi-year continuous operation in API 670-compliant machinery protection systems.

Logistics from Xiamen to international destinations:

• Express courier (DHL / FedEx / UPS): 2–4 business days to most global destinations
• Standard air freight: 5–10 business days
• Sea freight (bulk orders): Available on request for large-quantity procurement
• Export documentation: Commercial invoice, packing list, Certificate of Origin, HS code 8543.70.9000
• Minimum order: 1 unit; volume pricing available for orders of 5 units or more
• Warranty: 12 months from shipment date, covering manufacturing defects and calibration drift beyond ±0.254 V/mm

Contact Information

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