Eddy Current Probes

Proximity sensors work on the eddy current principle. A proximity system consists of an eddy current probe, extension cable and driver. A high-frequency RF signal is generated by the driver, sent through the extension and probe cables and radiated from the probe tip. The tip consists of a precision wound copper coil inside a chemical and temperature resistant PEEK case.

  • eddy current probe EPHD80

  •  eddy current probe EP080

  • eddy current driver

  • eddy current driver

  • eddy current driver

The tip is either mounted on a threaded stainless steel rod allowing easy gap adjustment on a bracket via two locking nuts or a flat, low profile mount. The driver demodulates the signal, amplifies and linearises it to provide an output proportional to the probe to target gap and/or vibration of the target.

External overview

The Eddy Current Probe consists of a precision-wound copper coil inside a chemical- and temperature-resistant PEEK tip. This is mounted on a threaded stainless steel rod for easy gap adjustment or a flat, low-profile mount. It is supplied with 1m of integral overbraided coaxial cable. Operates up to 180˚C. Operating gap depends on the tip diameter. Can be used with any driver.

Current output drivers give a 4-20mA output directly proportional to the measured component and allow direct connection to PLCs and other industrial controllers. Can be used with any probe type.


MTN/EP080The most common probe for high speed pumps with plain metal bearings able to measure small vibration levels and gaps up to 2mm.



  • Probe Diameter: 5mm
  • Operating Gap: 0 - 2mm
  • Body Length: 37mm
  • Thread: M8



MTN/EP200Used to measure coarser vibrations.



  • Probe Diameter: 13mm
  • Operating Gap: 0 - 5mm
  • Body Length: 62mm
  • Thread: M16



MTN/EP200FAs MTN/EP200 but in low-profile mount.



  • Probe Diameter: 13mm
  • Operating Gap: 0 - 5mm
  • Mount: Flat, three-point mounting


MTN/EP340Generally used for precision gap measurements.



  • Probe Diameter: 20mm
  • Operating Gap: 0 - 8.5mm
  • Body Length: 75mm
  • Thread: M20



MTN/EP340FAs MTN/EP340 but in a low-profile mount.



  • Probe Diameter: 13mm
  • Operating Gap: 0 - 8.5mm
  • Mount: Flat, three-point mounting


MTN/EP480Widest gap capability.



  • Probe Diameter: 25mm
  • Operating Gap: 0 - 12mm
  • Body Length: 99mm
  • Thread: M30



MTN/EPHD80This heavy-duty eddy current probe system is designed for the greatest protection from harsh industrial conditions. Rugged IP65 cast aluminum driver housing with integral probe. Stainless steel probe sleeve tailored to exact insertion depth required and the probe can be exchanged without recalibration. Unit can be based on any driver type highlighted in this guide. Particularly suited to thrust or vibration measurements on pumps and turbines.

  • Probe Diameter: 5mm
  • Operating Gap: 0 - 2mm
  • Insertion Length: As required
  • Protection: IP65
  • Entry: M20

Extension Cable

Eddy current probes are supplied with 1m of integral cable which can be extended to 9m (by the addition of up to 8m of extension cable). However, long cables will often give installation problems as they need to be rotated during the gap set-up process; in which case screw-on extension cables are recommended. However, once a system has been manufactured and calibrated with an extended cable it can only be exchanged or renewed with one of equal length and the system will require recalibration.

  • Type: Coaxial, ETFE insultaion, copper braid
  • Overbraid: Stainless steel
  • Maximum Length: 8 metres
  • Connectors: SMC to match probe and driver

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Monitran Product Range



Ideal for use with portable and on-line vibration analysers.

monitoring systems

Monitoring Systems

Monitoring systems that can be used to measure vibration.



Switch Enclosures and Connection Enclosures by Monitran.

linear variable differential transformer


LVDT'S are a popular tansducer in industrial applications.

eddy current probes and drivers


The latest precision-wound copper coil Proximity Sensors.



Allowing the user access to a vibration sensor for machinery.

Established in 1986, Monitran remains a privately owned company, based near High Wycombe 35 miles west of London.

We manufacture in the United Kingdom and source the majority of our materials and components from selected quality-managed local and national suppliers.

Call Us: +44 (0)1494 816569

Monitor House
33 Hazlemere Road
HP10 8AD