Proximity Probes & Transducers

Proximity probes and transducers measure shaft position, radial vibration, and axial movement on rotating machinery using non-contact eddy current technology, providing continuous shaft vibration measurement without physical contact with the rotating element. PLC Direct supplies proximity probes and proximity transducers from Bently Nevada, covering the 3300 XL eddy current transducer system and associated signal conditioning components used in installed machinery protection systems. Hardware is available as surplus sealed, refurbished, and used to support maintenance teams replacing failed components in existing rotating equipment monitoring installations.

Where Are Proximity Probes & Transducers Used in Industrial Environments?

Proximity probes and eddy current transducers are used on fluid film bearing machines where direct shaft vibration measurement is required for machinery protection and condition monitoring. They are standard on high-value rotating equipment in industries where a bearing or shaft fault that goes undetected can result in catastrophic damage or a forced plant shutdown.

Facilities and operations that depend on proximity probes and transducers include:

• Oil and gas refineries and petrochemical plants monitoring centrifugal compressors, steam turbines, and gas turbines where API 670 proximity probes are the required sensor standard for critical machinery protection.

• Power generation facilities using shaft proximity probes on large turbogenerators for continuous radial vibration and thrust position measurement.

• Petrochemical and chemical processing plants with high-speed rotating equipment requiring non-contact vibration measurement to meet safety and regulatory standards.

• Pulp and paper mills protecting high-speed rolls, fans, and compressors running in corrosive, high-temperature process environments.

• Mining and mineral processing operations monitoring large rotating equipment on conveyors, crushers, and process fans in remote installations.

When a proximity probe, extension cable, or Proximitor signal conditioner fails in an installed transducer system, a matched replacement set is required to restore accurate shaft vibration measurement and maintain machinery protection coverage.

Which Brands of Proximity Probes & Transducers Does PLC Direct Stock?

PLC Direct stocks proximity probes and transducers from Bently Nevada, whose eddy current transducer systems are the industry-standard sensor platform for critical rotating equipment monitoring across oil and gas, power generation, and process industries.

• Bently Nevada 3300 XL Proximity Probes: Eddy current probes in 8 mm, 11 mm, 14 mm, and 25 mm configurations for non-contact vibration measurement of radial shaft vibration, thrust position, and differential expansion on fluid film bearing machines; API 670 compliant and rated for high-temperature, high-pressure, and corrosive installations.

• Bently Nevada 3300 XL Proximitor Sensors: Signal conditioning electronics that power the proximity probe and convert the eddy current signal to a DC voltage output proportional to the gap between probe tip and shaft surface, forming the central component of the complete eddy current transducer system.

• Bently Nevada 3300 XL Extension Cables: Precision coaxial cables connecting the shaft proximity probe to the Proximitor sensor; cable length is encoded in the part number and must match the installed system configuration to maintain correct gap voltage and sensitivity calibration.

• Bently Nevada 3300 XL Vibration Transmitters: Signal conditioning components that convert proximity transducer output to a 4-20 mA signal for integration with DCS and PLC systems in balance-of-plant rotating equipment monitoring applications where dedicated monitor rack hardware is not installed.

All proximity probes and transducers at PLC Direct are available as surplus sealed, refurbished, or used, with condition noted on each product listing.

What Should You Know Before Ordering Proximity Probes & Transducers?

Hardware condition options: Proximity probes and transducers at PLC Direct are available as surplus sealed, refurbished, and used hardware. Surplus sealed units are factory-sealed stock in original packaging; refurbished units have been tested and restored to operational condition. Used hardware is inspected prior to listing and carries the same 1-year PLC Direct warranty as all other condition grades.

Compatibility and part identification: Bently Nevada proximity probes, extension cables, and Proximitor sensors must be ordered and installed as a matched transducer system; substituting components from different system configurations affects gap voltage, sensitivity, and measurement accuracy. The part number suffix on each component encodes probe diameter, body length, cable length, and sensitivity specification, so replacement hardware must be matched by direct part number rather than general specification. For API 670 proximity probe applications, confirm that the replacement system matches the installed configuration's gap and scale factor requirements before ordering.

Warranty: All proximity probes and transducer hardware purchased from PLC Direct carry a standard 1-year PLC Direct warranty covering defects and functionality, applicable to surplus, sealed, refurbished, and used products.

PLC Direct supplies proximity probe and transducer hardware for replacement and maintenance, and does not provide system design, programming, or integration services.