Bently Nevada 21000-16-10-15-144-03-02 Proximity Probe – 21000 Series

Bently Nevada 21000-16-10-15-144-03-02 Proximity Probe Housing Assembly — Eddy-Current Shaft Monitoring for Critical Rotating Machinery

The Bently Nevada 21000-16-10-15-144-03-02 is a 16 mm eddy-current proximity probe housing assembly with a 144-inch (3,658 mm) integral cable, designed for continuous non-contact measurement of shaft radial vibration, axial position, and differential expansion on rotating machinery. It operates as the primary sensing element within Bently Nevada’s 3300 XL and 3500 Series machinery protection architectures, delivering a calibrated voltage output that is linearly proportional to the gap between the probe face and the conductive target surface.

In a control loop context, this probe functions as the transducer stage: it converts mechanical displacement — measured in micrometers — into a DC voltage signal (nominally –2 VDC to –18 VDC across the linear range) that feeds directly into a Proximitor® sensor. The Proximitor conditions the signal and forwards it to a 3500 rack monitor card, which executes alarm and trip logic in hardware with deterministic response times below 20 ms. The probe’s mechanical accuracy and electromagnetic stability are therefore load-bearing elements of the entire protection chain.

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

Technical Parameters

Hardware Logical Analysis

The 21000-16-10-15-144-03-02 operates on the principle of high-frequency electromagnetic induction. The probe tip contains a wound coil driven by an oscillator circuit (typically 1 MHz carrier) embedded in the paired Proximitor sensor. When the probe tip approaches a conductive target, eddy currents are induced on the target surface, loading the oscillator and reducing coil impedance. This impedance change is demodulated into a DC voltage output with a scale factor of approximately –7.87 V/mm (–200 mV/mil), providing a linear, repeatable displacement signal.

EMC Design: The 16 mm probe body is constructed from 316 stainless steel, which provides both mechanical rigidity and magnetic shielding. The PTFE-jacketed coaxial cable maintains a controlled characteristic impedance along the full 144-inch run, suppressing common-mode noise pickup in high-EMI environments such as variable-frequency drive (VFD) motor rooms and high-voltage switchgear areas. The coaxial geometry ensures that radiated interference from adjacent power cables does not corrupt the low-level displacement signal.

Thermal Stability: The probe’s wound coil is encapsulated in a thermally stable compound rated to +177 °C, preventing coil geometry drift that would introduce scale-factor error at elevated bearing temperatures. This is particularly relevant in steam turbine applications where bearing housing temperatures routinely exceed 120 °C during steady-state operation.

Target Surface Interaction: The eddy-current field penetration depth is a function of target material conductivity and permeability. The 21000 series is factory-calibrated against AISI 4140 steel — the industry-standard shaft material for API 670 applications. When installed on non-standard target materials (e.g., Inconel, titanium alloys), a field calibration using the actual target material is required to maintain the specified ±1% linearity across the full measurement range.

Cable Impedance Matching: The 144-inch cable length encoded in the part number is not arbitrary — it is matched to the Proximitor sensor’s internal oscillator tuning. Substituting a cable of different length without re-tuning the Proximitor will shift the linear range and alter the scale factor, producing systematic measurement error. This part number guarantees a factory-matched cable-probe assembly that requires no field adjustment when paired with a compatible Proximitor.

System Integration Benefits

• Direct OEM Form-Fit-Function Replacement: The 21000-16-10-15-144-03-02 is a drop-in replacement for existing Bently Nevada 21000-series installations. No recalibration of the 3300 XL or 3500 rack monitor card is required, eliminating the need for a machinery protection system outage during probe replacement.
• Deterministic Trip Response: When integrated with a Bently Nevada 3500/40M or 3500/42M monitor card, the probe-to-trip chain executes alarm and danger logic in hardware with a response time under 20 ms — independent of host DCS or PLC scan cycles. This deterministic behavior is essential for overspeed and high-vibration trip applications where milliseconds determine whether a machine survives a fault event.
• Diagnostic Transparency via OK Relay: The Proximitor sensor paired with this probe continuously monitors the probe circuit’s impedance. If the probe cable is open-circuited, short-circuited, or the gap moves outside the linear range, the Proximitor de-energizes its OK relay, flagging a transducer fault to the 3500 rack without requiring operator intervention. This self-diagnostic capability reduces nuisance trips caused by undetected sensor failures.
• Multi-Parameter Measurement from a Single Probe: A single 21000-series probe installation can simultaneously provide radial vibration (AC component), average shaft centerline position (DC component), and slow-roll runout data to the monitoring system. This eliminates the need for separate displacement and vibration transducers on the same measurement plane, reducing installation complexity and cable routing costs.
• API 670 Compliance for Insurance and Regulatory Requirements: Many jurisdictions and insurance underwriters require API 670-compliant machinery protection on critical rotating equipment. The 21000 series is designed to meet these requirements, supporting compliance documentation for new installations and replacement projects.
• Compatibility Across Bently Nevada Monitor Generations: The probe is electrically compatible with 3300 XL, 3500, and legacy 7200 series monitoring racks. This cross-generation compatibility protects capital investment in existing monitoring infrastructure when probe replacement is required during a maintenance window.
• Reduced Spare Parts Inventory Complexity: The 21000 series uses a standardized coaxial connector interface. A single probe model covers radial vibration, axial position, and differential expansion measurement applications, allowing maintenance teams to consolidate spare parts inventory rather than stocking separate transducer types for each measurement function.
• Traceable Documentation Package: Each unit is available with a full documentation package including factory calibration certificate, material traceability record, country-of-origin certificate, and anti-counterfeit verification. This documentation supports quality management system (QMS) requirements under ISO 9001 and satisfies procurement audit requirements for critical spare parts.

Quality Assurance & Global Logistics

Every Bently Nevada 21000-16-10-15-144-03-02 unit supplied by siemensplc.com is sourced through verified distribution channels with documented supply chain traceability. Our incoming inspection process includes visual examination against OEM packaging and labeling standards, date code verification, dimensional checks on the probe tip and connector, and functional impedance testing of the coil assembly. Anti-counterfeit screening is applied to all units before acceptance into stock.

Units are stored in ESD-safe, climate-controlled conditions in our Xiamen, China warehouse. Shipments are packed in anti-static foam with moisture-barrier outer packaging, suitable for air freight and sea freight transit. We provide full export documentation for international orders: commercial invoice, packing list, certificate of origin, and HS code classification (HS 9031.80 — instruments for measuring or checking). Express air freight from Xiamen to major industrial hubs in Southeast Asia, the Middle East, Europe, and the Americas typically achieves delivery within 3–7 business days. For urgent maintenance requirements, same-day dispatch is available for in-stock units when orders are confirmed before 14:00 CST.

All units carry a 12-month warranty from the date of shipment, covering manufacturing defects and verified OEM specification non-conformance. Warranty claims are processed with a target response time of one business day.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
© 2026 siemensplc.com. All rights reserved.