Bently Nevada 330851 Modules - 330851-02-000-070-10-00-05

Technical Dossier

Product Details And Specifications

Bently Nevada 330851 Series Technical Notes

The Bently Nevada 330851 series comprises eddy-current proximity probes engineered for continuous, non-contact measurement of shaft displacement, vibration, and position in rotating machinery. These probes are a core sensing element within the Bently Nevada 3300 XL Proximity Transducer System, which holds a dominant installed base across global heavy industry — including petrochemical refineries, nuclear power stations, LNG processing facilities, offshore platforms, and large-scale turbomachinery installations. The 330851 probe is designed to operate in conjunction with 330180 extension cables and 330130 / 330180 series proximitors (signal conditioning modules), forming a calibrated transducer chain that delivers a standardized output of −200 mV/mil (−7.87 V/mm) into plant-level monitoring systems such as the System 1 condition monitoring platform.

In critical rotating equipment applications — steam turbines, gas compressors, centrifugal pumps, and gearboxes — the 330851 series provides the primary vibration and position data required for API 670-compliant machinery protection. Its deployment in safety-instrumented environments demands long-term parts availability, which is the primary driver for aftermarket sourcing of this series.

The Evolution of 330851 Architecture

The 330851 series is the successor to Bently Nevada's earlier 7200 and 3300 series proximity probe families. The transition from the 3300 series to the 3300 XL platform — introduced in the mid-1990s — brought tighter manufacturing tolerances, improved EMI shielding, and extended temperature ratings. The 330851 probe was designed to be backward-compatible with existing 3300 series cable and proximitor infrastructure in most installations, reducing retrofit costs during system upgrades.

Key architectural characteristics of the 330851 series include a threaded stainless steel housing (standard M10 × 1.0 or 5/16-28 UNF thread forms), a PTFE-jacketed coaxial cable integral to the probe body, and a tip diameter standardized at 5 mm or 8 mm depending on the sub-model. The probe operates on the eddy-current principle: a high-frequency oscillator in the proximitor drives the probe coil, and the impedance change caused by a conductive target surface is converted to a DC voltage proportional to gap distance.

As the 3300 XL platform has matured into a late-lifecycle phase, Bently Nevada (now a Baker Hughes company) has introduced the 3500 series as the current-generation replacement architecture. However, the installed base of 3300 XL systems in operating plants remains substantial, and direct replacement of 330851 probes does not require a full system migration — making long-term spare parts availability a critical operational requirement for maintenance engineers.

330851 Full Catalog & Functionalities (SKU List)

The following SKUs represent the primary configurations within the 330851 proximity probe series, differentiated by cable length, connector type, thread form, and temperature rating. Each model is a discrete, orderable part number.

330851-00-000-070-10-00-05: 5 mm tip, 1 m integral cable, standard temperature, M10 thread, no armor, metric connector.
330851-01-000-070-10-00-05: 5 mm tip, 1 m cable, standard temp, 5/16-28 UNF thread, no armor, metric connector.
330851-02-000-070-10-00-05: 5 mm tip, 2 m integral cable, standard temperature, M10 thread, no armor, metric connector.
330851-03-000-070-10-00-05: 5 mm tip, 3 m integral cable, standard temperature, M10 thread, no armor, metric connector.
330851-04-000-070-10-00-05: 5 mm tip, 4 m integral cable, standard temperature, M10 thread, no armor, metric connector.
330851-05-000-070-10-00-05: 5 mm tip, 5 m integral cable, standard temperature, M10 thread, no armor, metric connector.
330851-00-000-070-10-00-08: 8 mm tip, 1 m integral cable, standard temperature, M10 thread, no armor, metric connector.
330851-02-000-070-10-00-08: 8 mm tip, 2 m integral cable, standard temperature, M10 thread, no armor, metric connector.
330851-03-000-070-10-00-08: 8 mm tip, 3 m integral cable, standard temperature, M10 thread, no armor, metric connector.
330851-05-000-070-10-00-08: 8 mm tip, 5 m integral cable, standard temperature, M10 thread, no armor, metric connector.
330851-00-000-070-10-01-05: 5 mm tip, 1 m cable, standard temp, M10 thread, armored cable variant, metric connector.
330851-02-000-070-10-01-05: 5 mm tip, 2 m cable, standard temp, M10 thread, armored cable, metric connector.
330851-00-000-070-10-00-05-A: 5 mm tip, 1 m cable, high-temperature rating (up to 177°C), M10 thread, no armor.
330851-02-000-070-10-00-05-A: 5 mm tip, 2 m cable, high-temperature rating (up to 177°C), M10 thread, no armor.
330851-03-000-070-10-00-05-A: 5 mm tip, 3 m cable, high-temperature rating (up to 177°C), M10 thread, no armor.
330851-05-000-070-10-00-05-A: 5 mm tip, 5 m cable, high-temperature rating (up to 177°C), M10 thread, no armor.
330851-00-000-070-10-00-08-A: 8 mm tip, 1 m cable, high-temperature rating, M10 thread, no armor.
330851-02-000-070-10-00-08-A: 8 mm tip, 2 m cable, high-temperature rating, M10 thread, no armor.

All 330851 probes are passive sensing elements (no onboard electronics). Signal conditioning is performed by the paired proximitor module. The probe must be used as part of a calibrated system — substituting individual components without recalibration will affect measurement accuracy and may invalidate API 670 compliance.

Quality Control for the 330851 Range

Proximity probes are precision-calibrated transducers. The primary quality risk in the aftermarket supply chain is the use of probes that have been physically damaged (tip impact, cable kinking, connector damage) or that have drifted from their original calibration curve due to coil degradation or contamination. DriveKNMS applies the following verification protocol to all 330851 units prior to dispatch: