Product Overview

The Epro PR6424/014-000 16 mm Eddy Current Sensor is a non-contact displacement sensor designed for monitoring the operating condition of critical rotating machinery. It belongs to the PR6424 series developed for industrial machinery protection and condition-monitoring applications. The sensor is used to measure shaft displacement, vibration, axial or radial position, eccentricity, and rotational speed-related signals.

The PR6424 series is commonly applied to steam turbines, gas turbines, hydro turbines, compressors, pumps, and industrial fans. These machines often operate continuously under demanding mechanical and thermal conditions. Monitoring shaft movement helps maintenance personnel identify abnormal vibration, changes in shaft position, and potential mechanical problems before they develop into more serious equipment failures.

Unlike contact-based measurement devices, an eddy current sensor measures the distance between its sensing tip and a conductive target without physically touching the rotating shaft. This non-contact principle makes it suitable for continuous monitoring of rotating equipment.

The PR6424/014-000 has a nominal sensor head diameter of 16 mm and a supplied weight of approximately 0.2 kg. The PR6424 series uses a high-frequency electromagnetic measurement principle. When installed with a compatible signal converter and measurement system, the sensor can provide information about both static shaft position and dynamic shaft vibration.

The sensor is intended to operate as part of a complete measurement chain. Its performance depends on the probe, extension cable where required, signal converter, target material, installation gap, and monitoring equipment. Correct component matching is therefore essential when replacing an existing sensor or designing a new machinery-monitoring installation.

Technical Specifications

Note: The performance figures above describe the PR6424 series. Confirm the exact cable, connector, mounting thread, and temperature configuration for the PR6424/014-000 before installation or replacement.

Function and Working Principle

The PR6424/014-000 operates using the eddy current measurement principle. It generates an electromagnetic field near the sensing tip and measures changes in that field when a conductive target moves relative to the probe.

This allows the sensor to detect small changes in the distance between the probe and a rotating shaft without making physical contact.

1. Electromagnetic Field Generation

The sensing element contains a coil that generates a high-frequency electromagnetic field when supplied by a compatible signal converter.

When the sensor is positioned near a conductive target, such as a ferromagnetic steel shaft, the electromagnetic field interacts with the target surface.

The interaction produces eddy currents within the conductive material. These currents affect the electrical characteristics of the probe coil.

2. Distance Measurement

As the distance between the probe and the shaft changes, the strength of the interaction between the electromagnetic field and the target also changes.

The resulting electrical variation can be processed by the compatible signal converter to produce an output proportional to the measured gap.

This allows the monitoring system to identify changes in shaft position and movement.

3. Static Displacement Measurement

Static displacement monitoring is used to determine the relative position of a shaft. It can help detect changes in shaft alignment, axial position, or mechanical positioning.

The PR6424 series has a nominal static measurement range of ±2.0 mm. This range supports monitoring of shaft position within the specified operating and installation conditions.

4. Dynamic Vibration Measurement

Dynamic measurement focuses on the rapid movement of a rotating shaft around its operating position.

When the shaft vibrates, the distance between the shaft surface and the sensor changes continuously. The sensor detects these variations and provides a signal that can be processed by the machinery protection system.

This information can help maintenance personnel identify abnormal vibration patterns, mechanical imbalance, bearing-related problems, and other changes in rotating equipment behavior.

5. Signal Conversion

The sensor is part of a measurement chain rather than a standalone industrial transmitter. A compatible signal converter supplies the required excitation and processes the probe response.

Depending on the selected converter and monitoring equipment, the resulting signal can be used for shaft displacement, vibration, and position monitoring.

The probe, extension cable, converter, and monitoring input must be selected as a compatible system. Mixing components with different electrical characteristics or calibration requirements can result in inaccurate measurements.

Role in Industrial Machinery Protection Systems

The PR6424/014-000 can be installed as part of a machinery condition-monitoring system. It provides measurement information that helps operators and maintenance engineers assess the mechanical condition of critical rotating equipment.

1. Shaft Vibration Monitoring

Shaft vibration is an important indicator of rotating machinery condition. Excessive vibration may be associated with rotor imbalance, misalignment, bearing deterioration, looseness, or other mechanical problems.

The PR6424 sensor measures shaft movement without contacting the rotating surface. Its signal can be used by a compatible monitoring system to track vibration trends and identify changes in machine behavior.

2. Shaft Position Monitoring

Shaft position measurements help engineers observe changes in the relative position of rotating components.

This is particularly important in large turbines and compressors, where shaft movement can affect clearances, bearing conditions, and mechanical stability.

3. Eccentricity Measurement

Eccentricity monitoring helps identify irregular shaft geometry or changes in shaft position during rotation.

By observing the displacement signal, maintenance teams can investigate mechanical conditions that may contribute to uneven rotation or abnormal vibration.

4. Speed and Key-Related Measurement

A suitable measurement arrangement can also use the sensor signal for rotational speed or key-related monitoring functions.

The exact measurement capability depends on the target geometry, signal conditioning, sensor installation, and monitoring-system configuration.

5. Machinery Condition Assessment

Continuous monitoring provides operating data that can be compared with historical measurements and machine-specific alarm settings.

When vibration or displacement trends change, engineers can investigate the equipment and determine whether inspection or maintenance is necessary.

The sensor does not independently diagnose every mechanical fault. Its measurement data should be interpreted together with operating conditions, other instrumentation, and machinery protection logic.

Industrial Applications

The Epro PR6424 series is designed for non-contact measurement in critical rotating machinery. The PR6424/014-000 may be considered for applications where its electrical and mechanical configuration matches the monitoring system.

1. Steam Turbines

Steam turbines operate at high rotational speeds and require reliable monitoring of shaft movement and vibration.

Eddy current sensors can measure radial shaft displacement and other position-related parameters. This information supports machinery protection and maintenance planning.

The sensor can be used as part of a monitoring arrangement that helps identify abnormal shaft movement during normal operation and changing load conditions.

2. Gas Turbines

Gas turbines are used in power generation and industrial mechanical-drive applications. Their rotating components operate under demanding thermal and mechanical conditions.

Non-contact shaft monitoring helps engineers observe vibration and displacement behavior. The PR6424 series is designed for machinery-monitoring applications involving large rotating shafts.

3. Hydro Turbines

Hydroelectric generating equipment may experience changes in shaft movement due to hydraulic forces, operating load, bearing conditions, and mechanical alignment.

Shaft displacement measurements can help maintenance personnel monitor changes in rotating equipment behavior and investigate abnormal vibration trends.

4. Industrial Compressors

Large compressors are widely used in petrochemical plants, refineries, gas-processing facilities, and industrial production systems.

Continuous shaft vibration monitoring helps detect changes in mechanical condition. Eddy current sensors are particularly useful where non-contact measurement of shaft movement is required.

5. Pumps

Large industrial pumps may operate continuously in water treatment, power generation, chemical processing, and oil and gas facilities.

Shaft displacement and vibration measurements can help identify mechanical changes associated with bearing wear, misalignment, or rotor-related problems.

6. Industrial Fans

Large fans and ventilation systems are used in power plants, manufacturing facilities, and process industries.

Monitoring shaft vibration can help maintenance teams identify abnormal operating conditions and plan inspections before unexpected equipment shutdowns occur.

Installation and System Integration

Correct installation is essential for measurement accuracy and long-term reliability. The sensor must be installed according to the manufacturer’s mechanical and electrical requirements.

1. Confirm the Sensor Configuration

Before installation, verify the complete model number and sensor configuration. The PR6424 series includes different cable lengths, connectors, mounting arrangements, and other configuration options.

The /014-000 suffix should be checked against the actual product label and applicable documentation. Do not assume that every PR6424 sensor has identical cable or connector arrangements.

2. Check the Mounting Position

The sensor must be mounted securely and positioned toward the intended conductive target.

The mounting arrangement should maintain the required mechanical clearance and prevent the probe from contacting the rotating shaft during normal operation or expected shaft movement.

The sensor’s threaded sleeve and mounting hardware should be checked for compatibility with the machine installation.

3. Set the Initial Air Gap

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

The actual installation gap must follow the applicable sensor and converter documentation. Incorrect probe positioning can reduce measurement accuracy or cause the output to operate outside its intended linear range.

The air gap should be checked during commissioning and after any mechanical adjustment.

4. Verify Target Material

The standard PR6424 calibration is based on ferromagnetic steel, with 42CrMo4 used as the standard target material.

Different shaft materials can affect sensor response. If the actual target material differs from the standard, verify the calibration requirements with the manufacturer or system documentation.

5. Connect the Cable and Converter

Connect the sensor to its compatible extension cable and signal converter where required.

Cable length, connector type, electrical characteristics, and calibration compatibility should be checked before commissioning.

Avoid routing sensor cables close to high-power conductors or sources of strong electromagnetic interference where possible. Protect the cable from excessive bending, abrasion, vibration, and mechanical damage.

6. Integrate with the Monitoring System

The converted measurement signal can be connected to a suitable machinery protection or condition-monitoring system.

Depending on the monitoring architecture, the system may display shaft vibration, position, displacement, and alarm conditions.

Configure the measurement channel according to the sensor and converter specifications. Alarm limits should be based on the machine manufacturer’s recommendations and applicable machinery-monitoring requirements.

7. Commissioning and Verification

After installation, verify the probe position, cable connections, converter compatibility, and measurement-channel configuration.

Check the output under known operating conditions and compare the readings with expected values. Record the initial measurement baseline for future condition assessment.

Compatible System Components

A complete PR6424 measurement installation may include several components. Their compatibility must be confirmed according to the selected sensor configuration and monitoring-system design.

The components listed are examples of equipment used in PR6424 measurement systems. They are not necessarily included with the sensor. Confirm the exact probe, extension cable, converter, and monitoring-system combination before purchasing.

Alternative Models and Replacement Considerations

The PR6424 is part of the EPRO eddy current sensor family. Other models may be available for different measurement ranges, shaft sizes, or temperature requirements.

Before selecting a replacement, compare:

• Sensor head diameter.
• Full catalog number and suffix.
• Mounting thread and probe dimensions.
• Cable length and cable construction.
• Connector and extension-cable arrangement.
• Static and dynamic measurement ranges.
• Sensitivity and linearity.
• Target material and calibration.
• Operating temperature requirements.
• Signal converter compatibility.
• Monitoring-system input requirements.

A probe with the same 16 mm diameter is not necessarily a direct replacement. Differences in cable configuration, calibration, connector arrangement, and converter compatibility can affect the complete measurement chain.

Key Advantages

Non-Contact Measurement

The PR6424 sensor measures shaft movement without touching the rotating surface. This makes it suitable for continuous monitoring of high-speed rotating machinery.

16 mm Sensing Head

The 16 mm sensor head is designed for applications involving larger rotating shafts and critical machinery.

Static and Dynamic Measurement

The PR6424 series supports both shaft-position measurement and dynamic displacement measurement, allowing monitoring systems to observe different aspects of machine behavior.

High Measurement Sensitivity

The series provides a nominal sensitivity of 4 V/mm with a specified linearity of ≤±1.5% under its standard measurement conditions.

Industrial Machinery Applications

The sensor is designed for use with turbines, compressors, pumps, fans, and other rotating equipment requiring shaft displacement monitoring.

Stainless Steel Sleeve

The stainless steel sleeve provides a robust mechanical housing for the sensing assembly in industrial installations.

PTFE Cable Construction

The series uses PTFE cable insulation, supporting operation in demanding industrial environments within the applicable temperature limits.

Integration with Machinery Monitoring Systems

When matched with a compatible converter and monitoring equipment, the sensor can provide measurement data for machinery condition assessment and protection.

Technical FAQs

1. What is the Epro PR6424/014-000?

The PR6424/014-000 is a 16 mm eddy current sensor designed for non-contact measurement of shaft displacement, vibration, position, and related mechanical parameters in rotating machinery.

2. What is the sensor head diameter?

The nominal sensor head diameter is 16 mm.

3. What is the measurement range of the PR6424 series?

The standard static measurement range is ±2.0 mm. The recommended dynamic measurement range is 0 to 1,000 μm peak-to-peak.

4. What is the sensitivity?

The PR6424 series has a nominal sensitivity of 4 V/mm when used with the specified measurement arrangement and standard target material.

5. What is the nominal air gap?

The nominal center air gap is approximately 2.7 mm. The actual installation gap should follow the manufacturer’s instructions for the specific probe and converter combination.

6. Which materials can the sensor measure?

The standard calibration uses ferromagnetic steel, with 42CrMo4 as the reference material. Other target materials may require specific calibration or verification.

7. Does the sensor require a signal converter?

Yes. The PR6424 is part of an eddy current measurement chain and requires a compatible signal converter to provide the appropriate excitation and measurement output.

8. Which machines commonly use PR6424 sensors?

Typical applications include steam turbines, gas turbines, hydro turbines, compressors, pumps, and industrial fans.

9. What is the operating temperature range?

The PR6424 series documentation specifies temperature limits that depend on the sensor configuration. Typical published operating ranges extend from -35°C to +180°C. Check the exact configuration before installation.

10. What is the weight of the PR6424/014-000?

The supplied product weight is 0.2 kg. PR6424 series documentation also lists approximately 200 g for a sensor with a 1-meter cable without armor. Actual weight can vary with cable length and construction.

11. Can the PR6424/014-000 replace another PR6424 model?

Not automatically. The probe diameter may be the same, but cable length, connector type, mounting arrangement, and calibration can differ. Compare the full model number and measurement-chain requirements before replacement.

12. What should be checked if the sensor output becomes unstable?

Inspect the probe mounting, initial air gap, cable condition, connectors, converter compatibility, grounding, and target surface. Also check whether the shaft material and installation geometry match the sensor’s calibration requirements.

Procurement and Maintenance Recommendations

When purchasing the Epro PR6424/014-000, verify the complete model number and inspect the product label. The PR6424 family includes multiple configurations, so the probe should not be selected based only on its 16 mm diameter.

Confirm the cable length, cable armor, connector arrangement, mounting thread, and compatible converter. If the sensor is intended to replace an existing probe, compare the original model number and installation drawings before ordering.

For used or refurbished sensors, request clear photographs of the sensing head, threaded sleeve, cable, connector, and identification label. Check for damaged insulation, bent mounting sections, corrosion, contamination, or signs of mechanical impact.

During maintenance, inspect the probe mounting and cable routing. Ensure that the sensor remains securely positioned and that the cable is protected from abrasion, excessive bending, and heat exposure beyond its specified limits.

Keep records of the initial air gap, converter configuration, calibration information, and baseline measurement values. These records help maintenance teams identify changes in sensor performance and investigate abnormal machine readings.

For critical turbine and compressor installations, sensor replacement should be followed by appropriate commissioning and verification of the complete measurement chain. A physically compatible probe may still produce incorrect measurements if its converter or calibration settings do not match.

Conclusion

The Epro PR6424/014-000 16 mm Eddy Current Sensor is designed for non-contact shaft displacement and vibration measurement in critical rotating machinery. Its PR6424 series characteristics include a ±2.0 mm static measurement range, 4 V/mm sensitivity, and ≤±1.5% linearity under specified conditions.

With its 16 mm sensing head and approximately 0.2 kg supplied weight, the sensor is suitable for consideration in industrial machinery-monitoring applications involving turbines, compressors, pumps, and fans.

For reliable operation, the complete measurement chain must be correctly configured. Buyers and maintenance engineers should verify the exact probe suffix, cable arrangement, mounting requirements, converter compatibility, and calibration before purchasing or installing a replacement.