EPRO PR6424 Eddy Current Displacement Sensors — PR6424/010-040-CN

Technical Dossier

Product Details And Specifications

EPRO PR6424 Series: Comprehensive Module Range and Technical Overview

The EPRO PR6424 series is a family of eddy current displacement sensors manufactured by EPRO GmbH (a Baker Hughes / Bently Nevada group company), engineered for non-contact, continuous measurement of shaft radial vibration, axial position, and differential expansion in rotating machinery. These sensors are standard-fit in critical asset protection systems across global heavy industry: petrochemical refineries, nuclear power stations, offshore platforms, LNG terminals, and large-scale chemical processing plants. The PR6424 series is fully compatible with EPRO's CON021, CON041, and CON081 signal conditioning modules, and integrates directly into Bently Nevada 3500 series rack-based machinery protection systems. Installed base spans hundreds of thousands of measurement points across six continents, making the PR6424 one of the most widely deployed eddy current sensor families in industrial history.

The Evolution of PR6424 Architecture

The PR6424 series was introduced as part of EPRO's second-generation eddy current product line, succeeding the earlier PR6422 and PR6423 families. The core operating principle — electromagnetic induction between a coil-tipped probe and a conductive target surface — has remained unchanged, but successive revisions addressed three engineering challenges: cable length standardization, connector interchangeability, and EMI immunity in high-frequency drive environments.

Early PR6424 variants used proprietary EPRO extension cables (PR9376 series) with fixed impedance matching. Later revisions introduced the standardized TNC connector interface, enabling field replacement without recalibration in many installations. The introduction of the /CN suffix (e.g., PR6424/010-040-CN) denotes a cable-integrated, non-interchangeable probe-cable assembly — a design choice that eliminates connector resistance variation at the cost of modular replacement. Modern installations in new-build plants increasingly specify the PR6424 alongside digital output conditioning modules, though the analog 4–20 mA and ±24 V output variants remain dominant in brownfield retrofit projects where legacy DCS I/O cards are retained. The series is now in its mature/end-of-production lifecycle; EPRO's current active catalog directs new designs toward the PR6426 and PR9268 families, but the PR6424 remains the primary spare parts requirement for the installed base through at least 2035.

PR6424 Full Catalog & Functionalities (SKU List)

The following SKUs represent the verified, commonly stocked configurations within the PR6424 series. Each entry reflects a distinct probe diameter, cable length, and connector/termination variant.

PR6424/000-010-CN: 5 mm probe, 1 m integrated cable, non-interchangeable assembly, standard gap range 0–1.5 mm.
PR6424/000-040-CN: 5 mm probe, 4 m integrated cable, non-interchangeable, for extended conduit runs.
PR6424/010-010-CN: 8 mm probe, 1 m cable, radial vibration measurement, ±200 µm range.
PR6424/010-040-CN: 8 mm probe, 4 m integrated cable, standard radial vibration sensor, pairs with CON021/CON041.
PR6424/010-100-CN: 8 mm probe, 10 m cable, long-run installation for large turbine pedestals.
PR6424/020-010-CN: 11 mm probe, 1 m cable, increased sensitivity for low-conductivity target materials.
PR6424/020-040-CN: 11 mm probe, 4 m cable, axial position measurement, gap range 0–4 mm.
PR6424/020-100-CN: 11 mm probe, 10 m cable, axial thrust position on large steam turbines.
PR6424/030-010-CN: 14 mm probe, 1 m cable, high-temperature rated to 180 °C continuous.
PR6424/030-040-CN: 14 mm probe, 4 m cable, differential expansion measurement on turbine casings.
PR6424/030-100-CN: 14 mm probe, 10 m cable, long-run differential expansion, nuclear-grade installations.
PR6424/040-010-CN: 25 mm probe, 1 m cable, large-diameter shaft measurement, gap range 0–8 mm.
PR6424/040-040-CN: 25 mm probe, 4 m cable, compressor radial vibration, API 670 compliant.
PR6424/040-100-CN: 25 mm probe, 10 m cable, offshore platform compressor trains, corrosion-resistant housing.
PR6424/050-040-CN: 50 mm probe, 4 m cable, low-frequency displacement on slow-speed machinery, gap range 0–15 mm.
PR6424/060-040-CN: Flush-mount variant, 4 m cable, for installations with restricted axial clearance.
PR6424/080-040-CN: High-temperature variant, 4 m cable, rated to 230 °C, for hot-section turbine measurements.

Sourcing Hard-to-Find & Obsolete PR6424 Parts

EPRO has formally transitioned the PR6424 series to a reduced-support status, with OEM lead times for non-standard configurations extending to 16–26 weeks or classified as no-longer-available. DriveKNMS maintains a dedicated inventory program for PR6424 series components, sourced through authorized surplus channels and tested to original EPRO factory specifications. Our stock covers the full cable-length matrix (1 m, 4 m, 10 m) across all probe diameter variants, with particular depth in the /010-040-CN and /020-040-CN configurations that represent the majority of global installed base demand. For plants operating under long-term service agreements (LTSAs) or requiring multi-year spare parts kits, DriveKNMS provides consignment stocking arrangements with guaranteed availability SLAs. Emergency same-day dispatch is available for in-stock items to support unplanned outage recovery.

Quality Control for the PR6424 Range

Each PR6424 unit processed by DriveKNMS undergoes a structured verification protocol before dispatch. Probe coil impedance is measured at 1 kHz using a precision LCR meter and compared against EPRO's published nominal values (±5% tolerance). Cable continuity and insulation resistance are verified at 500 V DC, with a minimum acceptance threshold of 100 MΩ. The integrated cable-probe assembly is inspected for jacket integrity, connector seating, and strain relief condition. Where a compatible CON021 or CON041 conditioning module is available, functional end-to-end testing is performed: the sensor is positioned at the nominal gap distance above a certified AISI 4140 steel target, and the output voltage linearity is verified across the full measurement range. All test results are documented and supplied with the unit on a serialized test certificate. Units that do not meet specification are quarantined and not returned to stock.