Product Overview

The EPRO PR6424/103-000 16 mm Eddy Current Sensor is a non-contact displacement sensor designed for monitoring the operating condition of large rotating machinery. It belongs to the EPRO PR6424 sensor family, which is used in machinery protection and condition-monitoring applications involving turbines, compressors, pumps, fans, and other critical rotating equipment.

The sensor operates using the eddy current measurement principle. It generates an electromagnetic field near a conductive target, typically a ferromagnetic steel shaft. Changes in the distance between the sensor tip and the target influence the electromagnetic response. The corresponding measurement signal can then be processed by a compatible signal converter and monitoring system.

Unlike contact-based measurement devices, an eddy current probe does not need to touch the rotating shaft. This makes it suitable for continuous measurement of shaft movement without introducing mechanical contact between the probe and the monitored surface.

The PR6424 family is designed for applications requiring measurement of radial and axial shaft displacement, shaft position, eccentricity, and speed-related characteristics. Its 16 mm sensor head is intended for larger rotating machinery, with a typical reference shaft diameter of 80 mm or greater.

The PR6424 series has a nominal sensitivity of 4 V/mm and a static measurement range of ±2.0 mm. Its dynamic measurement range is specified as 0 to 1,000 μm peak-to-peak. These characteristics make the series suitable for machinery monitoring systems where accurate shaft movement information is important for identifying changes in operating condition.

The PR6424/103-000 is identified as a specific ordering variant. When selecting a replacement or integrating it into an existing monitoring system, users should confirm the complete model number, cable length, connector arrangement, mounting dimensions, and compatible converter.

Technical Specifications

Note: The technical performance values above describe the PR6424 sensor family. The approximately 200 g manufacturer reference weight applies to a sensor with 1 m cable and without armor. Exact cable length, connector, thread, and mechanical dimensions for the PR6424/103-000 should be confirmed against the product label and applicable ordering documentation.

Function and Working Principle

The PR6424/103-000 belongs to a family of non-contact sensors that use electromagnetic induction to measure the distance between the probe and a conductive target. Its measurements can be used by a machinery monitoring system to evaluate shaft movement and operating condition.

1. Non-Contact Eddy Current Measurement

The sensor creates an alternating electromagnetic field around its measuring tip. When a conductive metal target approaches the probe, eddy currents are induced in the target surface.

The strength of these currents changes according to the distance between the sensor and the target. The sensor system converts this change into an electrical measurement signal.

Because measurement takes place without physical contact, the probe can monitor a rotating shaft continuously without rubbing against its surface.

2. Shaft Displacement Measurement

One of the main functions of the PR6424 family is measuring shaft displacement. The sensor can be installed near a shaft surface to detect changes in the distance between the probe and the rotating component.

In machinery monitoring applications, this measurement can help identify abnormal shaft movement, changes in bearing clearance, or variations in the machine’s operating condition.

The measurement direction depends on the probe’s installation orientation. Radial probes are positioned to monitor movement perpendicular to the shaft axis, while axial probes are arranged to monitor movement along the shaft axis.

3. Shaft Vibration Monitoring

The sensor can provide displacement information used to evaluate shaft vibration. When a rotating shaft moves relative to the probe, the sensor output changes accordingly.

A compatible monitoring instrument processes the measurement signal and can calculate vibration-related values for machinery protection and condition assessment.

This information is particularly useful for large rotating equipment, where changes in shaft vibration may indicate mechanical imbalance, misalignment, bearing deterioration, or other developing problems.

4. Position and Eccentricity Measurement

The PR6424 family can also be used for shaft position and eccentricity monitoring.

Position measurements provide information about the shaft’s location relative to the probe. Eccentricity measurements help identify deviations in the shaft’s geometric or rotational behavior.

These measurements can support maintenance teams when evaluating machinery alignment, rotor condition, and changes in mechanical clearances.

5. Signal Conversion and Monitoring

An eddy current sensor normally operates as part of a measurement chain rather than as a standalone display device.

A compatible signal converter supplies the required sensor excitation and processes the probe response into a usable output. The resulting signal can be connected to a machinery protection system, vibration monitoring unit, or suitable data acquisition equipment.

The probe, extension cable where applicable, converter, and monitoring input must be compatible as a complete measurement system.

Role in Industrial Machinery Monitoring Systems

The EPRO PR6424/103-000 can serve as a sensing element in machinery protection and condition-monitoring installations. It provides shaft-related measurement information that can be used by monitoring equipment to assess machine behavior.

Turbine Monitoring

Steam and gas turbines operate at high rotational speeds and may experience changing thermal and mechanical conditions. Shaft displacement and vibration measurements help operators observe rotor behavior during startup, normal operation, and shutdown.

A properly installed PR6424 sensor can provide measurement information for a compatible turbine monitoring system.

Compressor Condition Monitoring

Industrial compressors often operate continuously and are important to production processes. Shaft movement monitoring can help maintenance teams identify changes in mechanical condition.

Measurements from suitable probes can be used alongside bearing temperature, vibration, pressure, and operating data to provide a more complete view of compressor performance.

Pump Monitoring

Large industrial pumps may be exposed to hydraulic forces, changing loads, and continuous operating cycles. Shaft displacement monitoring can provide additional information about rotating assembly behavior.

The probe must be installed at an appropriate measurement location and configured for the pump’s mechanical arrangement.

PLC and DCS Integration

A compatible signal converter or monitoring system can provide measurement outputs for a PLC or distributed control system.

The PLC or DCS may use these values for process monitoring, alarm handling, data recording, and coordination with other plant equipment. The exact integration method depends on the converter and monitoring hardware used.

The PR6424 probe itself should not be assumed to provide a direct standard PLC signal without the required signal-conditioning equipment.

Industrial Applications

The PR6424 16 mm sensor family is designed for critical rotating machinery applications where continuous shaft measurement is required.

1. Steam Turbines

Steam turbines are commonly used in power generation and industrial energy systems. Shaft displacement and vibration monitoring can help operators evaluate rotor movement and identify abnormal mechanical behavior.

A non-contact sensor is suitable for this type of installation because it can monitor the shaft without making physical contact with the rotating surface.

2. Gas Turbines

Gas turbines operate under demanding thermal and mechanical conditions. Continuous monitoring of shaft movement can contribute to machinery protection and maintenance planning.

The PR6424 series provides a measurement option for compatible turbine monitoring arrangements. Installation conditions and temperature exposure must be evaluated carefully.

3. Industrial Compressors

Large compressors are widely used in petrochemical facilities, refineries, gas processing plants, and manufacturing operations.

Shaft displacement and vibration information can help identify changes in rotor behavior. This information may be used together with other operating measurements to support predictive maintenance.

4. Industrial Pumps

Large pumps used in water treatment, power generation, and process industries may require continuous condition monitoring.

The sensor can be applied to suitable pump arrangements where shaft position or displacement measurements are required.

5. Fans and Blowers

Industrial fans and blowers may operate for extended periods under changing load conditions. Shaft monitoring can provide additional information about mechanical stability and rotating assembly behavior.

The sensor must be selected and installed according to the fan’s shaft arrangement and the required measurement direction.

6. Generators and Rotating Equipment

Generators and other large rotating machines require reliable monitoring of rotor movement and mechanical condition.

A compatible eddy current measurement system can provide shaft-related information for machinery monitoring and maintenance applications.

Installation and System Integration

Correct installation is essential for measurement accuracy and reliable operation. The probe must be matched to the target material, installed with an appropriate measurement gap, and connected to a compatible converter.

1. Verify the Complete Model Number

Before installation, confirm that the sensor is the correct PR6424/103-000 variant.

The PR6424 family includes multiple ordering configurations. Cable length, armor, connector type, probe length, and mounting details may differ between variants.

A replacement should match the original configuration or be approved for the intended measurement chain.

2. Confirm the Target Material

The PR6424 series is specified for ferromagnetic steel targets, with 42CrMo4 steel used as the standard reference material.

Different target materials can affect sensor calibration and measurement behavior. If the monitored shaft uses a different material, verify that the sensor and converter are suitable for that target.

3. Set the Measurement Gap

The PR6424 family has a nominal center air gap of approximately 2.7 mm.

The final installation gap should be established according to the manufacturer’s calibration and installation instructions. Incorrect probe positioning can reduce the usable measurement range or cause the output to operate outside its intended linear region.

4. Select the Correct Mounting Position

The probe must be installed according to the measurement objective.

For radial displacement monitoring, the sensor is normally positioned near the shaft surface in a radial direction. For axial position monitoring, the probe is arranged to measure movement along the shaft axis.

Mounting brackets and probe holders should provide sufficient mechanical stability to prevent unwanted movement during machine operation.

5. Connect the Compatible Converter

The sensor must be connected to a compatible signal converter. The converter provides the required excitation and processes the sensor signal.

Confirm the converter model, connector type, cable configuration, and electrical requirements before connecting the probe.

Do not assume that different PR6424 cable or connector variants can be exchanged without checking system compatibility.

6. Route and Protect the Cable

The sensor cable should be routed away from high-power conductors, switching equipment, and sources of electromagnetic interference where practical.

Avoid sharp bends, excessive pulling force, and mechanical damage. The cable and connector should be protected from oil, heat, vibration, and other environmental conditions according to their specifications.

7. Verify the Measurement Chain

After installation, check the probe connection, converter supply, measurement gap, and output signal.

Verify that the monitoring system displays a stable measurement under the expected operating conditions. Where possible, compare the reading with a known reference or commissioning measurement.

Record the installed probe position, cable arrangement, converter configuration, and baseline measurement values for future maintenance.

Compatible System Components

The PR6424/103-000 should be considered part of a complete measurement chain. The following equipment may be used in a compatible machinery monitoring installation, subject to the exact system design.

Not every component listed above is supplied with the sensor. Confirm the actual bill of materials before ordering a complete monitoring channel.

Alternative Models and Replacement Considerations

The PR6424 belongs to the EPRO 16 mm eddy current sensor family. Other PR6424 variants may share similar measurement characteristics, but they should not automatically be treated as direct replacements.

Before selecting an alternative, compare:

• Sensor head diameter.
• Probe length and mounting thread.
• Cable length and cable construction.
• Connector type and connection arrangement.
• Measurement range and sensitivity.
• Target material and calibration.
• Operating temperature.
• Compatible signal converter.
• Monitoring-system input requirements.

A similar sensor diameter does not guarantee measurement-chain compatibility. The probe, cable, converter, and monitor should be evaluated together.

Key Advantages

Non-Contact Measurement

The sensor measures shaft movement without physical contact, reducing mechanical wear at the sensing point.

Suitable for Large Rotating Machinery

The 16 mm PR6424 family is designed for applications involving large shafts, including turbines, compressors, pumps, and fans.

Shaft Displacement Monitoring

The sensor provides measurement information for radial and axial shaft movement, position, and eccentricity monitoring.

Stable Measurement Characteristics

The PR6424 family specifies sensitivity of 4 V/mm, linearity of up to ±1.5%, and long-term drift below 0.3%.

Industrial Temperature Capability

The current PR6424 specification sheet gives a sensor operating temperature range of -35°C to +150°C. The exact limits should be confirmed for the complete probe configuration and installation environment.

Integration with Machinery Monitoring Systems

When paired with a compatible converter and monitoring equipment, the sensor can contribute to continuous machinery condition monitoring and protection.

Established EPRO Sensor Platform

The PR6424 family is used in industrial machinery monitoring applications where reliable shaft displacement measurements are required.

Technical FAQs

1. What is the EPRO PR6424/103-000?

The EPRO PR6424/103-000 is identified as a 16 mm eddy current sensor variant in the PR6424 family. It is designed for non-contact measurement of shaft displacement and related mechanical characteristics in rotating machinery.

2. What is the measuring principle?

It uses the eddy current principle. The sensor generates an electromagnetic field, and changes in the distance to a conductive target affect the sensor response. A compatible converter processes this response into a measurement signal.

3. What is the sensor head diameter?

The PR6424 family uses a 16 mm sensor head.

4. What is the sensitivity of the PR6424 series?

The typical sensitivity is 4 V/mm, with a specified linearity of up to ±1.5% under the stated reference conditions.

5. What is the static measurement range?

The PR6424 family has a static measurement range of ±2.0 mm.

6. What is the dynamic measurement range?

The specified dynamic measurement range is 0 to 1,000 μm peak-to-peak. The actual usable range depends on the measurement setup and operating conditions.

7. Which materials can the sensor measure?

The standard PR6424 specification uses ferromagnetic steel, specifically 42CrMo4, as its reference target material. Other target materials should be checked for calibration and compatibility.

8. Does the sensor connect directly to a PLC?

The probe is normally used with a compatible signal converter and monitoring system. A PLC can receive suitable signals from the converter or monitoring equipment, depending on the system design.

9. What should be checked if the sensor output is unstable?

Check the probe-to-shaft gap, mounting stability, cable and connector condition, converter compatibility, grounding, target surface, and electrical interference. Also confirm that the sensor is installed within its specified measurement range.

10. Can another PR6424 variant replace the PR6424/103-000?

Not automatically. Different variants may have different cable lengths, connectors, probe lengths, armor, and mounting configurations. Compare the complete ordering code and measurement-chain requirements before replacement.

Procurement and Maintenance Recommendations

When purchasing the EPRO PR6424/103-000, verify the complete model number and inspect the product label. Because the PR6424 family includes several mechanical and cable configurations, confirming the suffix is important for avoiding an incorrect replacement.

For a replacement project, compare the probe head diameter, mounting thread, total probe length, cable length, connector, and compatible converter. If the existing sensor is part of a machinery protection system, also confirm the monitoring channel’s calibration and configuration requirements.

For used or surplus units, request clear photographs of the sensor head, cable, connector, and identification label. Inspect the probe tip and cable for physical damage, and confirm the product’s condition before installation.

During maintenance, keep the probe mounting secure and inspect the cable routing and connector condition. Monitor the measurement output for unexpected drift or instability. Record baseline values and compare subsequent readings to help identify changes in machinery behavior.

The probe should be handled carefully during storage and installation. Avoid damaging the sensing tip, bending the cable beyond its permitted radius, or applying excessive force to the connector.

Conclusion

The EPRO PR6424/103-000 16 mm Eddy Current Sensor is intended for non-contact shaft displacement measurement in critical rotating machinery. The PR6424 family provides a typical sensitivity of 4 V/mm, a static measurement range of ±2.0 mm, and a dynamic measurement range of 0–1,000 μm peak-to-peak.

When used with a compatible converter and machinery monitoring system, the sensor can provide important measurement information for turbines, compressors, pumps, fans, and other large rotating equipment.

For maintenance and replacement projects, the complete ordering code, mounting configuration, cable arrangement, connector, and converter compatibility should be verified before installation.