Bently Nevada 21000-28-05-00-076-04-02 Proximity Probe – 3300 XL Series

Bently Nevada 21000-28-05-00-076-04-02: 8mm Eddy Current Proximity Probe for Turbomachinery Condition Monitoring

The Bently Nevada 21000-28-05-00-076-04-02 is a precision 8mm eddy current proximity probe belonging to the 3300 XL / 21000 Series platform — the de facto standard for shaft vibration and position measurement in API 670-compliant turbomachinery protection systems. Deployed across gas turbines, steam turbines, centrifugal compressors, and large rotating machinery in petrochemical, power generation, and LNG facilities worldwide, this probe delivers sub-micron displacement resolution with a flat frequency response from DC to 10,000 Hz. Its non-contact sensing principle eliminates mechanical wear, making it suitable for continuous, uninterrupted operation in environments where bearing failure carries catastrophic consequences.

Unlike general-purpose inductive sensors, the 21000-28-05-00-076-04-02 is factory-calibrated against a standardized AISI 4140 steel target at a nominal gap of 1.0 mm (40 mil), producing a bias output of –10 VDC and a sensitivity of 7.87 V/mm (200 mV/mil). This calibration is traceable to the Bently Nevada driver ecosystem — specifically the 3300 XL and 3500 Series monitor racks — ensuring that no field re-calibration is required upon installation. The probe body is rated to 177°C continuous, with the coaxial reverse-SMA connector providing a low-impedance, shielded signal path that resists capacitive coupling from adjacent high-voltage cabling in motor control centers and switchgear rooms.

This listing covers genuine Bently Nevada OEM units sourced through verified supply channels, shipped from our Xiamen, China warehouse with full documentation support. For pricing, lead time, and quantity availability, contact [email protected].

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

Technical Parameters

Hardware Logical Analysis

The 21000-28-05-00-076-04-02 operates on the Lenz’s law eddy current principle: a high-frequency oscillator within the paired driver (e.g., 3300 XL driver) energizes the probe coil at approximately 1 MHz, generating an alternating magnetic field at the probe tip. When a conductive target enters this field, eddy currents are induced on the target surface, loading the oscillator circuit and producing a measurable change in coil impedance. The driver converts this impedance shift into a DC-proportional voltage output — linear across the 0.25–2.54 mm measurement range.

EMC Design: The integral armored cable uses a double-shielded coaxial construction with a drain wire bonded at the driver end only, preventing ground loops that would introduce 50/60 Hz noise into the displacement signal. The probe body’s stainless steel housing acts as a Faraday shield, attenuating radiated RF interference from variable-frequency drives and high-current bus bars common in turbomachinery auxiliary systems. Measured EMC immunity exceeds IEC 61000-4-3 Level 3 (10 V/m) across the 80 MHz – 1 GHz band.

Thermal Stability: The probe coil is wound on a ceramic bobbin with a low thermal coefficient of expansion (<5 ppm/°C), maintaining sensitivity within ±1% across the full –35°C to +177°C operating range. This is critical for hot-section installations near turbine exhaust casings where ambient temperatures fluctuate by 80–120°C during load transients.

Mechanical Robustness: The 316L stainless steel housing provides corrosion resistance in H₂S-bearing atmospheres (NACE MR0175 compatible) and withstands the vibration levels specified in IEC 60068-2-6 (10–2,000 Hz, 20 g). The reverse-SMA connector’s positive-locking thread prevents accidental disconnection under the mechanical vibration present at bearing pedestals.

Target Material Sensitivity Correction: For non-AISI 4140 targets (e.g., titanium alloys, Inconel 718), the effective sensitivity deviates from the nominal 7.87 V/mm. Bently Nevada publishes target material correction factors; for titanium, the corrected sensitivity is approximately 4.5 V/mm, requiring driver gain adjustment or use of a target material correction module within the 3500 rack.

System Integration Benefits

• Zero-recalibration installation: Factory calibration against AISI 4140 at 1.0 mm nominal gap means the probe installs directly into a 3300 XL or 3500 rack without field sensitivity adjustment, reducing commissioning time by 2–4 hours per measurement point.
• API 670 compliance out of the box: The probe meets all dimensional, sensitivity, and frequency response requirements of API 670 (5th Edition) for radial vibration and axial position measurement, eliminating the need for third-party validation testing during plant acceptance.
• Deterministic signal latency: The DC–10,000 Hz flat response ensures that shaft vibration events at 1× and 2× running speed (typically 25–200 Hz for 1,500–12,000 RPM machines) are captured without phase distortion, preserving the integrity of orbit plots and Bode diagrams used in rotor dynamic analysis.
• Seamless 3500 rack integration: The probe’s reverse-SMA output connects directly to Bently Nevada 3500/42M, 3500/44M, and 3500/46M I/O modules. The rack’s built-in probe OK circuitry monitors gap voltage continuously; a gap outside –2 VDC to –18 VDC triggers a Not OK alarm without requiring external signal conditioning.
• System 1 software compatibility: Displacement data from this probe streams natively into Emerson System 1 condition monitoring software via the 3500 rack’s Ethernet gateway, enabling trend analysis, alarm management, and predictive maintenance workflows without additional signal conversion hardware.
• Redundant measurement architecture support: Two probes mounted 90° apart (X–Y configuration per API 670 §5.3) provide full shaft orbit reconstruction. The 21000-28-05-00-076-04-02’s matched sensitivity tolerance of ±1% between probe pairs ensures orbit circularity error remains below 2%, meeting the acceptance criteria of most OEM turbine manufacturers.
• Diagnostic transparency: The probe’s analog output voltage is directly readable with a standard DVM, allowing field technicians to verify gap setting and probe health without specialized test equipment. A reading of –10 VDC ±0.5 VDC at the nominal 1.0 mm gap confirms correct installation.
• Long-term spare parts availability: As a current-production Bently Nevada part number, the 21000-28-05-00-076-04-02 is supported under Baker Hughes’ long-term availability commitment, with a published minimum 10-year production horizon. This reduces lifecycle risk for plant operators managing 20–30 year asset depreciation schedules.

Quality Assurance & Global Logistics

Every unit of the Bently Nevada 21000-28-05-00-076-04-02 supplied by siemensplc.com is sourced through verified OEM and authorized distributor channels. Pre-shipment inspection covers visual examination of the probe body and connector, dimensional verification of the 8mm tip diameter, and electrical continuity and insulation resistance testing of the integral cable assembly. A Certificate of Conformance (CoC) referencing the original Bently Nevada part number and lot traceability is available upon request for QA documentation packages.

Units are packaged in anti-static foam-lined cartons with desiccant inserts, protecting the coaxial connector and cable termination from humidity and mechanical shock during transit. Our Xiamen, China warehouse operates under a documented inventory management system with FIFO rotation, ensuring no aged stock is dispatched.

Logistics from Xiamen reach major industrial hubs efficiently: DHL Express to Rotterdam in 3–5 business days, FedEx International Priority to Houston in 4–6 business days, and air freight consolidation to Singapore, Dubai, and Mumbai in 2–4 business days. For urgent plant shutdowns requiring same-day dispatch, contact our team before 14:00 CST. Export documentation including commercial invoice, packing list, and HS Code 9031.80 classification is prepared for all international shipments. All units carry a 12-month warranty from the date of shipment, covering manufacturing defects under normal operating conditions.

Contact Information

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