About Proximity Probes, Sensors & Transducer Systems

Customers who rely on mission-critical machinery choose our proximity probe sensors to monitor machine conditions and protect important equipment assets. We have many sensor types available for your object detection and temperature range needs. Whether you are looking for inductive proximity sensors, magnetic proximity sensors, ultrasonic proximity sensors, photoelectric sensors, or capacitive proximity sensors, these sensor types can help with object detection, automation, and robotics. Our high-speed, low-cost products have a long service life as well. Here’s a look at our high-speed sensor types. .

Proximity Sensor

Bently Nevada Proximity Probes & Transducer Systems
5mm, 8mm, 11mm Proximity Sensors
3300 5mm Proximity Probe. Sensor and Transducer System

The 3300 5mm Proximity Transducer System offers a smaller probe diameter while interfacing with XL 8mm extension cable and 5mm proximity sensor.  The system provides an output voltage that is directly proportional to the distance between the probe tip and the observed conductive surface.  The system can measure both static (position) and dynamic (vibration) data. Its primary use is in vibration and position measurement applications on fluid-film bearing machines, as well as Keyphasor measurement and speed measurement applications

The 3300 5mm Proximity Transducer System includes:

3300 XL 8mm Proximity Probe, Sensor and Transducer System

The 3300 XL 8 mm system delivers the most advanced performance in our eddy current proximity transducer systems. The standard 3300 XL 8mm 5-meter system also fully complies with the American Petroleum Institute's (API) 670 Standard (4th Edition) for mechanical configuration, linear sensing range, accuracy, and temperature stability. All 3300 XL 8mm proximity transducer systems provide this level of performance and support complete interchangeability of probes, extension cables, and Proximitor† sensors, eliminating the need to match or bench calibrate individual components for the sensing surface.

The 3300 XL 8mm Proximity Transducer System includes:

3300 XL 11mm Proximity Probe, Sensor and Transducer System

Our 3300 XL 11 mm Proximity Transducer System is our standard eddy current proximity measurement system. It accommodates a variety of applications with a linear measurement sensing range of 4 mm (160 mil) and provides a 3.94 V/mm (100 mV/mil) output to measure vibration and displacement. The 11 mm tip gives this Transducer System a longer linear sensing range when the standard 8 mm lacks sufficient reach. With both European and North American approvals, the 330 XL 11mm allows for installation in Hazardous Areas.

Bently Nevada's 3300 11mm Proximity Transducer System consists of:

16mm, 25mm and 50mm Proximity Sensor Systems
3300 XL 16mm High-Temperature Turbine Sensor System

Bently Nevada†’s 3300 XL High-Temperature Proximity System (HTPS) withstands extreme temperatures (rated for +350°C or +662°F). This high-temperature sensor is suitable for use inside gas turbines, steam turbines and other types of rotating machinery.

The 16mm system measures:

  • Vibration
  • Thrust position
  • Differential expansion
  • Mode shape analysis
  • Seal clearance
  • Labyrinth seals
  • Bearing housing struts in steam turbines
  • Exhaust path in gas turbines.
3300 XL 25mm Turbine Sensor and Transducer System

The 3300 XL 25mm Proximity Transducer System provides an extended linear measurement range of 12.7 mm (500 mil) and is ideal for use in steam turbine TSI (Turbine Supervisory Instrumentation) systems. The 3300 XL 25 mm Transducer System measures differential expansion (DE) on mid-size to large steam turbine generators caused by the difference in growth rates between the turbine rotor and the machine stator (casing), and plays a vital role in any comprehensive TSI system. The 25mm probe can survive in the harshest steam turbine differential expansion environments. The 25mm Proximitor Sensor has RFI/EMI immunity to achieve European CE mark approvals without special mounting considerations.

3300 XL 50mm Turbine Sensor and Transducer System 

Our 3300 XL 50 mm Proximity Transducer System offers the longest linear measurement of all of our eddy current proximity sensor systems with a sensing range of 27.9 mm (1100 mil). The 3300 XL 50 mm system measures the differential expansion (DE) between the rotor and stator of large steam turbine generators and is a vital input for Turbine Supervisory Instrumentation (TSI) systems.

The 50 mm system is capable of withstanding the harshest steam turbine environment. The RFI/EMI immunity of our 50 mm Proximitor sensor enables its European CE mark approvals without special mounting considerations.

Specialty Proximity Sensor Systems
3300 XL Ceramic Probe

When you need to monitor machinery in corrosive, chemical, or high-pressure environments, the 3300 XL Ceramic Capped Probe is your best choice. Featuring an Alumina ceramic cap and 304 stainless steel probe casing, the 3300 XL Ceramic Capped probe provides robust protection for applications in anhydrous ammonia or other extreme pH environments. While the 3300 XL CCP is rated to 34 Bar (500 psi), it can be modified for applications with higher pressures. Compatible with the 8 mm 3300 XL Proximitor Sensor and its extension cable.

3300 XL NSv Compressor Sensors

When your counterbore clearances are too small for standard Proximity Sensor and Transducer Systems, he 3300 XL NSv (narrow side view) Proximity Transducer System is here to help. Suitable for centrifugal air compressors, refrigeration compressors, process gas compressors and other machines with tight installation requirements, the 3300 XL NSv is also ideal for small targets such as measuring radial vibration on shafts smaller than 51 mm (2 in) or an axial position on flat targets smaller than 15 mm (0.6 in). Additionally, this sensor serves tachometer, zero speed and Keyphasor applications.

3300 XL Underwater Probe

3300 XL underwater probes are designed specifically for applications involving constant exposure to liquids, such as those in hydroelectric plants or sewage treatment facilities. These designs also seal the probes against gases. All our underwater probes are rated to 500 psi (34 Bar) on the interface between the tip and probe casing.

Proximity Probe Housing Assemblies
PROXPAC XL Proximity Transducer Assembly

Our 3300 PROXPAC XL Transducer Assembly integrates our Proximitor sensor with a specially-designed probe housing to create a compact, self-contained, all-in-one proximity probe system. An advanced thermoplastic called Polyphenylene Sulfide (PPS) is molded with glass and conductive fibers to strengthen the housing and effectively dissipate the danger of electrostatic charges. The housing cover contains its own 3300 XL Proximitor sensor connector, thus eliminating the need for an extension cable. Rated Type 4X and IP66 – the 3300 PROXPAC XL provides extra protection in severe environments.

Why Bently Sensors?

proximity sensor


More than 60 years ago Don Bently launched his first industrial product: the eddy current proximity sensor. The decades since that achievement have seen the quality and diversity of our high-quality proximity sensors evolve to include transducers that detect the presence of acceleration, velocity, and pressure. The proximity switch levels cover a variety of sensing distance needs.

Today’s high-performance eddy current proximity sensors deliver continuous condition monitoring information and trip monitored machines when needed to support a proactive maintenance program and machinery diagnostics.

Our industry-leading proximity sensor solutions offer superior performance and interchangeability in harsh environments with full API 670 compliance on applicable options. Here are a few benefits of our proximity sensor systems:

  • Reduces Costs - When you use our proximity sensors as part of your plantwide monitoring program, your costs associated with insurance, maintenance, and unscheduled repairs will go down significantly
  • Increases Revenue - Conversely, when you use our proximity sensors as part of your plantwide monitoring program, revenue will increase through increased uptime and production quality. Our inductive sensors have a long service life.
  • Minimizes Unplanned Outages - You can convert unplanned and costly outages into planned, manageable downtime.

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Proximity probe system interchangeability

Don't build a "Frankenstein" system!

Q2 2021 Proximity Probe Orbit Article

Supporting Hardware, Software & Services
Compatible Protection and Condition Monitoring Hardware

Our customers often find that these hardware products work well with the Proximity Sensors:

3500 - Machine Monitoring and Protection System

ADAPT Overspeed - Overspeed Protection and Shutdown System

ORBIT 60 - Next-Generation Monitoring and Protection System

ADAPT, 2300, and 1900/65 Systems - Distributed Protection

Sensor Accessories - Housings, Junction Boxes, Mounting Brackets

Compatible Condition Monitoring Hardware

Our customers often find that these condition monitoring hardware products work well with the Proximity Sensors:

  • VbOnline Pro
  • Trendmaster Pro

While all machinery may not warrant continuous, dedicated machinery protection from Bently Nevada 3500, 2300, ADAPT or 1900/65A Monitoring Systems, they require more frequent surveillance than the weekly, monthly, or quarterly rounds made with a portable data collection instrument.  Bently Nevada has the right online condition monitoring system for your assets with these online condition monitoring hardware products.

Compatible Software

Our Proximity Sensors work hand-in-hand with the following software:

System 1 - Analytic Insights

Compatible Services

Bently Nevada offers the following services that will support your Proximity Sensors in keeping your machinery in the best condition:


  • System Maintenance & Availability
  • Site Project Management
  • Design, Installation & Commissioning

Product Specifications
8mm Proximity Sensor - 3300 XL Proximitor Sensor

The 3300 XL Proximitor Sensor incorporates numerous improvements over previous designs. Its physical packaging allows you to use it in high-density DIN-rail installations.

You can also mount the sensor in a traditional panel mount configuration, where it shares an identical 4-hole mounting “footprint” with older Proximitor Sensor designs.

The mounting base for either option provides electrical isolation and eliminates the need for separate isolator plates.

The 3300 XL Proximitor Sensor is highly immune to radio frequency interference, allowing you to install it in fiberglass housings without adverse effects from nearby radio frequency signals. The 3300 XL Proximitor Sensor’s improved RFI/EMI immunity satisfies European CE mark approvals without requiring special shielded conduit or metallic housings, resulting in lower installation costs and complexity.

The 3300 XL’s SpringLoc terminal strips require no special installation tools and facilitate faster, more robust field wiring connections by eliminating screwtype clamping mechanisms that can loosen.

Proximitor Sensor Temperature Range

Operating Temperature -52°C to +100°C (-62°F to +212°F)

Storage Temperature -52 °C to +105 °C (-62 °F to +221 °F)

Probe Relative Humidity -  Less than a 3% change in Average Scale Factor (ASF) when tested in 93% humidity in accordance with IEC standard 68 2 3 for up to 56 days.

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