EMERSON PR6424/000-110 CON021/914-100 Proximity Probe – Bently Nevada 3300 XL

EMERSON PR6424/000-110 + CON021/914-100: Eddy Current Proximity Probe Assembly in the Bently Nevada 3300 XL Measurement Chain

The PR6424/000-110 is a non-contact eddy current proximity probe manufactured by EMERSON under the Bently Nevada product line. Paired with the CON021/914-100 extension cable (9.14 m / 30 ft), this factory-calibrated assembly forms a complete signal-transmission chain for continuous shaft displacement measurement in rotating machinery protection systems. The probe operates on the principle of electromagnetic induction: a high-frequency oscillator circuit within the probe tip generates an alternating magnetic field; when a conductive target (shaft) enters the field, eddy currents are induced on the target surface, loading the oscillator and producing a gap-proportional voltage output. This output is then conditioned by a Bently Nevada Proximitor driver and fed into a 3300 XL series monitor for alarm, trip, and trending functions.

The assembly is fully compliant with API 670 (5th Edition) requirements for machinery protection systems and is the standard replacement component for OEM-installed probe sets on steam turbines, gas turbines, centrifugal compressors, and large pumps across petrochemical, power generation, and LNG processing facilities.

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Technical Parameters

Hardware Logical Analysis

The PR6424/000-110 probe tip houses a precision-wound coil embedded in a thermally stable epoxy matrix. The coil forms the inductive element of an LC oscillator circuit whose resonant frequency is nominally set at 1.0 MHz. As the conductive shaft surface approaches the probe tip, eddy current losses increase, reducing the effective Q-factor of the oscillator and attenuating the oscillation amplitude. The Proximitor driver demodulates this amplitude-modulated carrier into a DC voltage with a linear transfer function of 7.87 V/mm across the calibrated gap range of 0.25–2.25 mm.

EMC Design: The coaxial construction of the CON021/914-100 extension cable provides continuous 360° shielding, with the shield terminated at the Proximitor chassis ground. This topology suppresses common-mode interference from variable-frequency drives (VFDs), high-current bus bars, and RF sources typically present in turbomachinery enclosures. The probe body itself is constructed from 316L stainless steel, which provides both corrosion resistance and magnetic neutrality — preventing the probe housing from acting as a secondary inductive element that would distort the field geometry.

Thermal Stability: The epoxy encapsulant used in the probe tip has a low coefficient of thermal expansion (CTE), matched to the coil winding material. This minimizes thermally induced drift in the scale factor across the –35°C to +120°C operating range. In practice, scale factor variation due to temperature is held within ±0.5% of nominal across the full operating band — a critical requirement for axial position measurements where a 25 µm drift can trigger a spurious alarm in tightly configured protection systems.

Calibration Traceability: Each probe-cable assembly is calibrated as a matched pair at the factory against a reference target of AISI 4140 steel. The calibration data is encoded in the Proximitor driver, which stores the probe serial number and associated scale factor. Substituting a cable of different length or type without recalibration shifts the total system impedance and introduces a predictable but uncorrected offset error — typically 2–5% per meter of cable length deviation from the calibrated value.

Redundancy Architecture Compatibility: The PR6424/000-110 is designed for use in dual-probe redundant configurations per API 670 Section 5.3. In a 2-out-of-2 (2oo2) voting architecture, two probes are mounted 90° apart on the same bearing journal. The 3300 XL monitor performs vector summation of the two displacement signals to compute the shaft orbit, enabling detection of asymmetric wear patterns and bearing instability that a single-plane measurement cannot resolve.

System Integration Benefits

• Direct 3300 XL Monitor Compatibility: The PR6424/000-110 interfaces without adaptation to all Bently Nevada 3300 series monitors (3300/16, 3300/20, 3300/55, 3300/65), preserving existing wiring infrastructure and eliminating re-termination labor during replacement.
• Zero-Wear Measurement Principle: Non-contact eddy current sensing eliminates mechanical contact with the rotating shaft, removing wear as a failure mode and enabling continuous 24/7 operation across multi-year maintenance intervals.
• DC-to-10 kHz Bandwidth: The flat frequency response from DC captures slow-roll runout at startup (typically 1–5 Hz) while the 10 kHz upper limit resolves blade-pass frequencies on high-speed compressors operating at 15,000–20,000 RPM.
• API 670 Compliance: The assembly meets all electrical and mechanical requirements of API 670 (5th Edition) for radial vibration, axial position, and differential expansion channels, supporting direct use in SIL-rated machinery protection loops.
• ATEX Zone 1/Zone 2 Certification: Intrinsically safe design allows installation in gas-hazardous areas without additional barriers in most configurations — consult the ATEX certificate for specific entity parameters before installation in Zone 0 areas.
• Orbit Plot Data Quality: The 7.87 V/mm scale factor and low noise floor (<25 mV RMS) deliver sufficient signal-to-noise ratio for high-resolution shaft orbit plots, enabling accurate diagnosis of oil whirl, misalignment, and rub conditions in the frequency domain.
• Matched-Pair Calibration: Factory calibration of probe and extension cable as a unit eliminates the field calibration step required when mixing unmatched components, reducing commissioning time by approximately 2–4 hours per measurement point.
• IP67 Environmental Sealing: The probe body withstands direct oil mist, steam condensate, and wash-down exposure without degradation of the coil assembly or connector seal — a practical requirement in turbine bearing pedestals where oil leakage is routine.

Quality Assurance & Global Logistics

Every PR6424/000-110 + CON021/914-100 assembly dispatched from our Xiamen, China facility is sourced through verified industrial distribution channels with full part traceability. Pre-shipment inspection covers connector pin integrity, cable jacket continuity, probe tip concentricity, and label legibility against EMERSON factory specifications. New-in-box stock is available with original EMERSON packaging and calibration documentation upon request.

Counterfeit mitigation is a standing protocol: each unit undergoes dimensional cross-check of the probe tip diameter, coil impedance measurement at 1 MHz, and visual comparison of connector finish against reference samples. Units that fail any inspection criterion are quarantined and not dispatched.

Logistics from Xiamen cover all major international freight lanes. Standard air freight to Europe, the Middle East, and Southeast Asia typically achieves 3–5 business days door-to-door. North American destinations are served in 5–7 business days via express courier. For critical unplanned shutdowns, same-day dispatch is available for in-stock units confirmed before 14:00 CST. All shipments include a commercial invoice, packing list, and — for new-in-box units — the original EMERSON calibration certificate. Export documentation for ATEX-certified equipment is prepared in compliance with destination country import requirements.

Contact Information

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