Bently Nevada 128987-130-01-05 Proximity Probe – 3300 XL Series

Bently Nevada 128987-130-01-05 — Eddy-Current Proximity Probe for API 670 Machinery Protection Systems

The 128987-130-01-05 is an 8 mm eddy-current proximity probe within Bently Nevada’s 3300 XL Proximity Transducer System, engineered for continuous non-contact measurement of radial shaft vibration and axial position on critical rotating machinery. With a 5-metre integral coaxial cable (suffix -05) and a standardized Bently Nevada coaxial connector, this probe interfaces directly with 3300 XL extension cables and 330180-series Proximitor sensors without requiring loop recalibration when used as a like-for-like replacement. Its deployment spans gas turbines, centrifugal compressors, steam turbines, boiler feed pumps, and expanders in refineries, LNG terminals, power generation plants, and offshore platforms — wherever API Standard 670 machinery protection is mandated.

The operating principle relies on high-frequency electromagnetic field generation at the probe tip. When the probe tip is positioned within the linear range (typically 0.25 mm to 2.25 mm gap for 8 mm probes on steel targets), eddy currents are induced in the conductive target surface. The resulting impedance change in the probe coil is processed by the Proximitor into a DC voltage output proportional to the gap distance, with a nominal sensitivity of −7.87 V/mm (−200 mV/mil). This voltage signal feeds directly into Bently Nevada 3500 Series monitors or equivalent machinery protection racks, where it is compared against alarm and danger setpoints defined per API 670 and the machinery OEM’s vibration acceptance criteria.

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Technical Parameters

Hardware Logical Analysis

The 128987-130-01-05 probe body is constructed with a precision-wound sensing coil encapsulated in a thermoplastic tip rated for continuous exposure to bearing housing temperatures up to 177 °C. The coil geometry is matched to the 3300 XL Proximitor’s oscillator circuit, which drives the probe at a fixed carrier frequency — typically in the range of 500 kHz to 2 MHz — to maintain consistent eddy-current penetration depth across the specified target materials. This frequency-locking architecture eliminates sensitivity drift caused by cable impedance variation, a common failure mode in generic proximity probes that use unmatched cable-probe combinations.

The 5-metre integral coaxial cable uses a tri-axial shielding configuration: an inner shield tied to the probe coil ground, an outer shield connected to the Proximitor chassis ground, and a drain wire for low-impedance EMC bonding at the terminal end. This construction attenuates common-mode noise from variable-frequency drives (VFDs), high-voltage switchgear, and RF sources present in industrial environments, maintaining signal integrity at the Proximitor input to within ±1% of the nominal sensitivity across the full operating temperature range.

The probe tip thread (M10 × 1.0 standard for 8 mm probes) and the integral cable strain relief are designed to withstand continuous vibration loads up to 20 g (10–2000 Hz) without connector fretting or coil deformation. The coaxial connector at the cable terminus is gold-plated to prevent oxidation-induced contact resistance increase — a critical detail in installations where the connector may be exposed to humidity, H₂S, or hydrocarbon vapors in oil and gas environments. The connector locking mechanism provides a positive retention force of ≥15 N to prevent accidental disconnection under vibration.

System Integration Benefits

• Direct 3300 XL Loop Compatibility: The probe’s electrical characteristics — coil inductance, Q-factor, and cable capacitance — are factory-matched to the 3300 XL Proximitor oscillator, ensuring the system operates within the OEM-specified linear range without field recalibration when replacing a like-for-like unit.
• Deterministic Vibration Data Latency: The eddy-current measurement chain from probe tip to Proximitor output introduces less than 1 ms of signal latency, preserving the time-domain fidelity required for synchronous vibration analysis (1X, 2X, sub-synchronous) in Bently Nevada System 1 or equivalent condition monitoring platforms.
• API 670 Alarm Setpoint Integrity: Because the probe sensitivity is held to ±3% of nominal (−7.87 V/mm), alarm and danger setpoints configured in the 3500 Series monitor remain valid without adjustment after probe replacement, reducing commissioning time and eliminating the risk of setpoint drift.
• Diagnostic Transparency via Gap Voltage: The DC gap voltage output provides a continuous, real-time indication of probe-to-shaft gap. Operators can monitor gap voltage trends to detect probe fouling, shaft centerline migration, or bearing wear before vibration amplitude alarms are triggered — enabling condition-based maintenance rather than time-based replacement.
• EMC Robustness in Mixed-Voltage Environments: The tri-axial cable shielding and Proximitor’s differential input architecture reject common-mode interference from adjacent 480 VAC motor cables, VFD outputs, and high-current bus bars, maintaining a signal-to-noise ratio sufficient for detecting vibration amplitudes as low as 1 µm peak-to-peak.
• Thermal Stability Across Process Conditions: The probe tip encapsulant maintains dimensional stability from cryogenic service (LNG expanders, −35 °C) to high-temperature steam turbine bearing housings (177 °C), without requiring temperature compensation adjustments at the Proximitor or monitor level.
• Redundant Measurement Architecture Support: The 128987-130-01-05 can be installed in dual-probe configurations (XY radial measurement planes) on the same bearing journal, feeding independent Proximitor channels and monitor input cards to satisfy API 670 redundancy requirements for critical machinery trains.
• Minimal Installation Footprint: The 8 mm probe body diameter and M10 thread allow installation in compact bearing housings where larger 11 mm or 25 mm probes cannot be accommodated, without compromising measurement sensitivity or linear range.

Quality Assurance & Global Logistics

Every 128987-130-01-05 unit supplied by siemensplc.com is sourced as genuine Bently Nevada (Baker Hughes) OEM hardware. Units are procured through verified industrial surplus channels, authorized distributor networks, or direct OEM supply lines, and each unit undergoes a structured pre-shipment verification protocol:

• Part Number & Date Code Verification: The probe body label, cable markings, and connector engravings are cross-referenced against Bently Nevada OEM part number records to confirm authenticity and production batch traceability.
• Physical Integrity Inspection: Probe tip encapsulant, cable jacket, strain relief, and coaxial connector are inspected under magnification for cracks, delamination, corrosion, or mechanical damage that could affect measurement accuracy or IP67 integrity.
• Coil Continuity Check: Probe coil DC resistance is measured and compared against the OEM specification band to screen for open-circuit or shorted coil conditions prior to shipment.
• Anti-Static Packaging: Units are individually packed in anti-static foam-lined enclosures with protective end caps on the probe tip and connector, sealed in moisture-barrier bags with desiccant, and labeled with part number, serial number, and inspection date.

Shipments originate from Xiamen, China, with access to major international freight forwarders and express courier networks (DHL, FedEx, UPS). Standard export documentation — commercial invoice, packing list, certificate of origin — is provided with every shipment. Expedited air freight to Europe, the Middle East, Southeast Asia, and the Americas is available with typical transit times of 3–7 business days. All units are shipped with a 12-month warranty covering manufacturing defects and verified OEM authenticity.

Contact Information

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