Bently Nevada 21000-28-10-00-217-04-02 Proximity Probe Assembly – 3300 XL Series

Bently Nevada 21000-28-10-00-217-04-02: Eddy-Current Proximity Probe Assembly for Critical Rotating Machinery Protection

The Bently Nevada 21000-28-10-00-217-04-02 is a factory-configured, non-contact eddy-current proximity probe assembly engineered for continuous shaft radial vibration and axial position measurement in turbomachinery protection systems. Operating as the primary sensing element within the Bently Nevada 3300 XL and legacy 7200 Series monitoring architectures, this assembly delivers a calibrated, matched-set measurement chain — probe tip, extension cable, and proximitor interface — that satisfies the stringent requirements of API 670 machinery protection standards across power generation, petrochemical refining, and heavy rotating equipment installations.

The part number suffix structure of the 21000 series encodes cable length, tip diameter, connector type, and target material compatibility. The 21000-28-10-00-217-04-02 configuration specifies an 8 mm tip diameter with a defined cable length and BNC-compatible termination, optimized for direct integration with Bently Nevada 3300 XL proximitor/oscillator-demodulator modules without field recalibration. This makes it the preferred OEM-equivalent replacement for installed monitoring loops on steam turbines, gas turbines, centrifugal compressors, and large rotating equipment where measurement traceability and system continuity are non-negotiable.

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

Technical Parameters

Hardware Logical Analysis

The 21000-28-10-00-217-04-02 operates on a three-node eddy-current signal chain. The probe tip coil generates a high-frequency electromagnetic field at approximately 1 MHz. When a conductive ferromagnetic shaft surface enters the field, eddy currents are induced in the target, loading the coil and shifting its impedance. This impedance variation is transmitted via the low-loss coaxial extension cable to the proximitor oscillator-demodulator, which converts the RF impedance modulation into a DC voltage output linearly proportional to the probe-to-shaft gap.

EMC Design: The probe body is constructed with a hermetically sealed, stainless-steel housing that provides both mechanical protection and electromagnetic shielding. The coaxial cable’s outer braid serves as a continuous Faraday shield, suppressing capacitively coupled interference from adjacent high-voltage cabling and variable-frequency drives — a common noise source in turbine hall environments. The proximitor’s internal oscillator circuit is designed with a high-Q resonant tank, maintaining frequency stability across the full operating temperature range and minimizing sensitivity drift caused by ambient thermal gradients.

Calibration Integrity: The probe, extension cable, and proximitor are factory-calibrated as a matched set. The cable’s distributed capacitance and inductance are accounted for in the proximitor’s demodulation algorithm. Field substitution of any single component without full system recalibration introduces a systematic gain error that cannot be corrected by zero-offset adjustment alone. This architecture enforces measurement traceability — a requirement under API 670 Section 5.3 for safety-critical protection loops.

Linearity and Resolution: Within the 0.25–2.25 mm linear range, the output voltage tracks gap displacement with a linearity error of less than ±1% of full scale. At 200 mV/mil sensitivity, the system resolves shaft displacements of less than 1 µm when paired with a 3300 XL monitor card operating at its standard 16-bit ADC resolution — sufficient to detect early-stage bearing wear before vibration amplitude reaches alarm thresholds.

System Integration Benefits

• Zero mechanical wear: Non-contact sensing eliminates probe degradation from shaft contact, supporting continuous 24/7 operation across multi-year maintenance intervals without scheduled probe replacement.
• DC-coupled measurement path: The DC–10 kHz frequency response captures both static shaft position (DC component) and dynamic vibration simultaneously on a single channel, eliminating the need for separate position and vibration transducers on the same bearing plane.
• Direct 3300 XL monitor card compatibility: The –2 to –18 VDC output maps directly to the input range of Bently Nevada 3300 XL monitor cards without signal conditioning, preserving the full 16-bit dynamic range of the monitor’s ADC and maintaining alarm/trip setpoint accuracy.
• API 670 protection loop compliance: Factory calibration documentation and certificate of conformance satisfy the traceability requirements of API 670, enabling direct use in safety instrumented systems without additional field verification beyond gap setting.
• Deterministic alarm response: The analog output signal reaches the monitor card with a propagation delay determined solely by cable length (approximately 5 ns/m for standard coaxial cable), ensuring that vibration events trigger protection relays within the monitor’s configured response time — typically under 20 ms for 3300 XL trip functions.
• Diagnostic transparency: The DC gap voltage provides a continuous, real-time indicator of bearing clearance change. A slow drift in the DC level — independent of vibration amplitude — signals shaft centerline migration, thermal growth, or bearing wear, enabling condition-based maintenance decisions before a vibration alarm is triggered.
• Multi-plane installation flexibility: The 8 mm tip diameter and compact probe body allow installation in radial and axial orientations within standard API 670 probe bracket geometries, supporting X-Y radial vibration pairs and thrust position measurement on the same shaft without bracket modification.
• Interoperability with DCS analog inputs: The –2 to –18 VDC output is compatible with standard 4–20 mA transmitter input cards via a signal conditioner, enabling parallel data acquisition by plant DCS historians for long-term trend analysis alongside the dedicated Bently Nevada protection system.

Quality Assurance & Global Logistics

Every Bently Nevada 21000-28-10-00-217-04-02 unit supplied through siemensplc.com is sourced from authorized distribution channels and verified OEM surplus with full documentation traceability. Prior to dispatch from our Xiamen, China facility, each assembly undergoes a structured pre-shipment inspection protocol: visual examination of probe tip, cable jacket, and connector termination; continuity and insulation resistance verification; and cross-check of part number markings against the original manufacturer’s label format.

Bently Nevada proximity probes are a documented target for counterfeit substitution in the aftermarket. Our procurement process requires full supply chain documentation — including distributor certificates of conformance and original manufacturer packing records — for every unit. No unmarked, relabeled, or undocumented stock is accepted.

Shipment is executed via DHL Express, FedEx International Priority, or UPS Worldwide, with standard transit times of 3–5 business days to major industrial hubs in Europe, the Middle East, Southeast Asia, and the Americas. Export documentation — commercial invoice, packing list, certificate of conformance, and HS code declaration — is prepared in compliance with destination country import requirements. For time-critical plant shutdowns, same-day dispatch is available for in-stock units when orders are confirmed before 14:00 CST.

All units carry a 12-month warranty against manufacturing defects from the date of shipment. Warranty claims are processed with replacement dispatch within 5 business days upon receipt and inspection of the returned unit.

Contact Information

For pricing, lead time confirmation, and technical pre-sales consultation:

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