Bently Nevada 330903-00-21-05-02-CN Proximity Transducer – 3300 XL Series

Bently Nevada 330903-00-21-05-02-CN — 3300 XL 8mm Eddy-Current Proximity Transducer System in Rotating Machinery Protection Loops

The 330903-00-21-05-02-CN is a complete eddy-current proximity transducer assembly from Bently Nevada’s 3300 XL Series, comprising an 8 mm probe, a 5 ft (1.5 m) integral armored cable, and a 21 ft (6.4 m) extension cable terminated for direct connection to a 3300 XL proximitor driver. The suffix -CN designates the China-market certification variant, carrying CNEX and CCC approvals in addition to the standard ATEX Zone 1 and IECEx ratings — making it the correct selection for hazardous-area installations subject to Chinese national safety regulations.

Within a machinery protection architecture, this transducer occupies the first stage of the signal chain: it converts mechanical displacement of a rotating shaft into a proportional DC voltage at a calibrated scale factor of 7.87 V/mm (200 mV/mil). That analog output feeds directly into Bently Nevada 3500 or 3300 series monitor cards, where it is processed against alarm and danger setpoints for radial vibration, axial position, or differential expansion — depending on the measurement plane and mounting configuration. The system’s DC-to-10 kHz (−3 dB) frequency response covers all sub-synchronous, synchronous, and harmonic vibration components relevant to API 670-compliant machinery protection on steam turbines, gas turbines, centrifugal compressors, and large pump trains.

Procurement teams and reliability engineers sourcing this part from Xiamen, China can expect factory-original units with full traceability documentation, shipped via DHL Express or FedEx International Priority. Stock availability is confirmed prior to invoice. Contact [email protected] for current pricing and lead time.

Real-time Stock & RFQ: [email protected] | WhatsApp: +86 18359268345

Technical Parameters

Hardware Logical Analysis

The 330903-00-21-05-02-CN operates on the principle of high-frequency eddy-current induction. The probe coil, driven by the proximitor at an oscillation frequency typically between 500 kHz and 2 MHz, generates an alternating electromagnetic field that penetrates the target surface. As the conductive target approaches or recedes, eddy currents induced in the target material load the coil, altering its impedance. The proximitor demodulates this impedance change into a linear DC voltage output — a process that is inherently non-contact and immune to contamination by oil mist, steam condensate, or particulate matter common in turbomachinery environments.

EMC Design: The integral armored cable between probe and extension cable junction serves a dual function: mechanical protection against abrasion in high-vibration bearing housings, and coaxial shielding that suppresses capacitive coupling from adjacent power conductors. The shield is grounded at the proximitor end only, forming a single-point ground topology that eliminates ground-loop interference — a critical design choice in plants where multiple monitoring loops share a common cable tray with variable-frequency drives and high-current motor feeders.

Target Material Sensitivity: The 7.87 V/mm scale factor is calibrated against AISI 4140 steel. Shafts fabricated from austenitic stainless steel (e.g., 316L) or titanium alloys exhibit different electrical conductivity and magnetic permeability, which shifts the effective scale factor by up to ±8%. For non-standard target materials, Bently Nevada provides material correction factors that must be applied at the monitor card configuration level. The -CN variant’s calibration certificate includes material correction data traceable to the factory standard.

Frequency Response Flatness: The DC-to-10 kHz bandwidth is not merely a headline figure — it is the result of a matched impedance design between the probe coil inductance, the extension cable’s distributed capacitance, and the proximitor’s input stage. Mismatching cable lengths (e.g., substituting a non-standard extension cable) introduces resonance peaks that distort the frequency response above 5 kHz, corrupting sub-harmonic and blade-pass frequency measurements. The 330903-00-21-05-02-CN’s 21 ft extension cable is factory-matched to the 8 mm probe to maintain response flatness across the full rated bandwidth.

System Integration Benefits

• Direct 3500/3300 monitor compatibility: The 7.87 V/mm scale factor is the native calibration constant for all Bently Nevada 3500 series I/O modules (e.g., 3500/40M, 3500/42M). No software scaling correction is required at commissioning, eliminating a common source of configuration error during plant startup.
• API 670 fifth-edition compliance: The transducer system meets the measurement accuracy, frequency response, and environmental requirements specified in API 670 for machinery protection systems on critical rotating equipment, supporting compliance documentation for insurance and regulatory audits.
• Dual-certification hazardous-area deployment: ATEX/IECEx and CNEX/CCC dual certification allows a single part number to be installed in both export-market and domestic Chinese facilities, reducing spare-parts inventory complexity for multinational operators.
• Deterministic signal latency: The analog output architecture introduces zero digital processing latency between shaft displacement and monitor input. In a 3500 series rack, the total signal chain latency from mechanical event to relay trip is governed solely by the monitor’s voting logic cycle time (typically <20 ms), not by transducer processing delay.
• Diagnostic transparency via gap voltage: The DC bias voltage at the proximitor output (nominally −10 VDC at mid-gap) provides a continuous, instrument-readable indicator of probe-to-shaft gap. Maintenance teams can verify correct installation gap (typically 1.0–1.5 mm for 8 mm probes) using a standard DVM without interrupting machine operation.
• Redundant measurement plane support: Two 330903-00-21-05-02-CN probes mounted at 90° in the X-Y plane provide the orthogonal displacement signals required for shaft orbit analysis in System 1 software, enabling detection of rotor bow, oil whirl, and rub events that single-plane measurements cannot resolve.
• Long-term spare-parts interchangeability: The 3300 XL probe interface has remained electrically unchanged across multiple product generations. A 330903-00-21-05-02-CN installed today is mechanically and electrically interchangeable with probes installed in 3300 series racks commissioned in the 1990s, protecting the capital investment in existing monitoring infrastructure.
• Reduced commissioning time: Factory-matched probe and extension cable assemblies arrive pre-tested with a calibration data sheet. Site commissioning is reduced to gap setting and gap voltage verification — typically under 30 minutes per measurement point — compared to multi-hour calibration procedures required for non-OEM assemblies.

Quality Assurance & Global Logistics

Every 330903-00-21-05-02-CN unit supplied by siemensplc.com is sourced as a genuine Bently Nevada (Baker Hughes) factory-original component. Units are not remanufactured, relabeled, or assembled from third-party sub-components. Each shipment is accompanied by a Certificate of Conformance (CoC) and, where available, the original factory calibration data sheet with traceable scale factor verification.

Pre-shipment inspection protocol: Visual examination of probe tip, cable jacket, and connector terminations for mechanical damage; label and part number verification against purchase order; packaging integrity check to confirm factory-sealed condition. For orders requiring additional assurance, third-party inspection by SGS or Bureau Veritas can be arranged at cost.

Logistics from Xiamen, China: Standard export shipments depart Xiamen Gaoqi International Airport via DHL Express or FedEx International Priority, with typical transit times of 3–5 business days to Southeast Asia, 4–6 days to Europe, and 5–7 days to North America. Sea freight via Xiamen Port is available for bulk orders. All shipments include commercial invoice, packing list, and certificate of origin. Export classification and HS code documentation are prepared in compliance with Chinese customs regulations and destination-country import requirements.

Warranty coverage is 12 months from the date of shipment. Warranty claims are processed with replacement unit dispatch within 5 business days of confirmed defect verification. Out-of-warranty repair assessment and exchange programs are available upon request.

Contact Information

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