Product Overview

The Epro PR6424/016-100 16 mm Eddy Current Sensor is a non-contact displacement sensor designed for monitoring the condition and operating behavior of critical rotating machinery. Manufactured under the EPRO product line associated with Emerson, the PR6424 series is widely used in machinery protection and condition-monitoring systems for turbines, compressors, pumps, fans, and other high-speed rotating equipment.

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 measurement principle allows the sensor to monitor shaft vibration, displacement, axial position, and eccentricity while minimizing mechanical wear at the sensing point.

The PR6424 series features a 16 mm sensor head and is designed for applications involving relatively large rotating shafts. Its measurement capabilities include static displacement measurement and dynamic vibration measurement. When paired with a compatible signal converter and monitoring system, the sensor provides information that can help operators identify abnormal shaft movement and assess machinery operating conditions.

The PR6424/016-100 is suitable for integration into industrial machinery monitoring installations where reliable shaft displacement measurement is required. Typical applications include steam turbines, gas turbines, hydro turbines, centrifugal compressors, industrial pumps, and large ventilation fans.

The sensor uses a nominal sensitivity of 4 V/mm with a specified linearity of approximately ±1.5%. Its static measurement range is ±2.0 mm, while its dynamic measurement range is 0 to 1,000 μm peak-to-peak. These characteristics make it suitable for monitoring both relatively slow shaft-position changes and dynamic vibration behavior.

With a sensor head diameter of 16 mm and a supplied listing weight of 0.2 kg, the PR6424/016-100 is a compact sensing component for machinery protection systems. For replacement projects, the complete model designation, cable configuration, connector type, and signal-converter compatibility should be checked before ordering.

Technical Specifications

Note: The technical values above describe the PR6424 16 mm sensor family. Confirm the exact /016-100 cable, connector, thread, temperature, and certification configuration against the product label and applicable documentation.

Function and Working Principle

The Epro PR6424/016-100 uses eddy current technology to measure the distance between the sensor tip and a conductive metallic target. The sensing system converts changes in this distance into an electrical signal that can be processed by a compatible signal converter.

1. Non-Contact Eddy Current Measurement

The sensor generates a high-frequency electromagnetic field around its sensing tip. When a conductive metal target, such as a rotating steel shaft, enters this field, eddy currents are induced in the target material.

These currents influence the electromagnetic characteristics of the sensor coil. As the distance between the sensor and the target changes, the electrical characteristics of the sensing circuit also change.

A compatible signal converter processes this variation and produces an output related to the measured gap. This allows the monitoring system to determine shaft movement without requiring physical contact between the probe and the rotating component.

2. Shaft Displacement Measurement

Shaft displacement monitoring is important for large rotating machinery. Changes in shaft position may result from bearing wear, mechanical deformation, thermal expansion, misalignment, or changes in operating conditions.

The PR6424 sensor can measure the distance between its sensing tip and the shaft surface. With the probe installed at an appropriate measurement position, the monitoring system can use the resulting signal to evaluate shaft displacement.

The PR6424 series provides a static measurement range of approximately ±2.0 mm, allowing it to monitor position changes within the specified measurement limits.

3. Shaft Vibration Monitoring

Rotating machinery naturally produces some vibration during operation. However, excessive vibration may indicate mechanical problems such as rotor imbalance, shaft misalignment, bearing deterioration, looseness, or abnormal operating conditions.

The PR6424 sensor measures dynamic changes in the distance between the probe and the rotating shaft. These changes can be processed by a compatible monitoring system to determine shaft vibration characteristics.

The series has a dynamic measurement range of 0 to 1,000 μm peak-to-peak. This capability supports machinery condition monitoring in applications where shaft vibration is an important operating parameter.

4. Eccentricity and Position Detection

Shaft eccentricity refers to the deviation of a shaft’s center from its intended rotational axis or geometric position. Excessive eccentricity may cause uneven mechanical loading and abnormal vibration.

By monitoring changes in the shaft-to-probe gap, the PR6424 sensor can provide measurement information for evaluating eccentricity and shaft position.

This information is useful during startup, normal operation, maintenance inspections, and machinery troubleshooting.

5. Signal Conversion and Monitoring

The sensor is one part of a complete measurement chain. A compatible signal converter processes the sensor’s electrical response and provides a usable output for monitoring equipment.

Depending on the installed system, the processed signal can be used by machinery protection equipment, monitoring modules, or industrial control systems.

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

Role in Industrial Machinery Protection Systems

The PR6424/016-100 is intended for use in machinery monitoring applications where shaft movement and vibration provide important information about equipment condition.

Turbine Monitoring

Steam, gas, and hydro turbines contain high-speed rotating assemblies that require continuous monitoring. Changes in shaft vibration or position may indicate developing mechanical problems.

The PR6424 sensor can be installed at suitable measurement locations to monitor radial or axial shaft movement. The resulting signals can be evaluated by a machinery protection system to help identify abnormal operating conditions.

Compressor Protection

Industrial compressors are used in oil and gas facilities, chemical plants, refineries, and power-generation installations. Their rotating components operate under demanding mechanical and thermal conditions.

The sensor can support compressor condition monitoring by measuring shaft displacement and vibration. These measurements can help maintenance teams identify changes in rotor behavior before they develop into more serious equipment problems.

Pump Monitoring

Large industrial pumps often operate continuously and may be critical to production processes. Bearing deterioration, shaft misalignment, and rotor imbalance can affect pump performance and reliability.

A non-contact eddy current sensor can monitor shaft movement without direct contact with the rotating component, providing useful information for machinery condition assessment.

Fan and Blower Monitoring

Large industrial fans and blowers may experience vibration caused by imbalance, bearing wear, mechanical looseness, or changes in operating conditions.

The PR6424 series can be considered for suitable shaft-monitoring installations where its measurement range and mechanical configuration meet the application requirements.

Industrial Applications

The Epro PR6424/016-100 is designed for industrial environments where reliable measurement of rotating machinery displacement and vibration is important.

1. Steam Turbines

Steam turbines are widely used in power-generation facilities and industrial energy systems. Their rotating shafts operate under high mechanical and thermal loads.

Continuous shaft monitoring helps operators evaluate rotor movement and identify abnormal vibration conditions. The PR6424 sensor can provide non-contact displacement measurements as part of an appropriate turbine monitoring system.

2. Gas Turbines

Gas turbines are used in power plants, industrial facilities, and mechanical-drive applications. Their high-speed rotating components require reliable monitoring to support safe and stable operation.

The sensor can be used to monitor shaft vibration, position, and eccentricity when installed with compatible monitoring equipment.

3. Hydro Turbines

Hydroelectric generating units contain large rotating assemblies that require long-term condition monitoring. Shaft movement and vibration measurements can help maintenance teams evaluate mechanical behavior during different operating conditions.

The PR6424 sensor is suitable for consideration in applications where a 16 mm non-contact eddy current probe meets the required measurement and installation specifications.

4. Centrifugal Compressors

Centrifugal compressors are common in oil and gas processing, petrochemical production, and industrial gas systems. Rotor stability is important for maintaining equipment availability.

The PR6424 series can measure shaft displacement and dynamic vibration, providing information for machinery monitoring and maintenance analysis.

5. Industrial Pumps

Large pumps used in power stations, refineries, and chemical plants may require continuous shaft monitoring. The sensor can support the detection of abnormal shaft movement and changing vibration conditions.

6. Industrial Fans and Blowers

Large fans and blowers may operate for extended periods in manufacturing plants, power facilities, and process industries. Shaft vibration measurements can help identify developing mechanical issues and support preventive maintenance programs.

Installation and System Integration

Correct installation is essential for achieving reliable measurement performance. The sensor must be mounted at the correct position, aligned with the target surface, and connected to compatible signal-processing equipment.

1. Sensor Mounting

The sensor should be installed at a suitable measurement location near the rotating shaft. The mounting arrangement must provide mechanical stability and maintain the required sensing clearance.

The probe should be positioned so that its sensing tip faces the intended target surface. Excessive mounting movement or vibration can affect measurement quality.

Check the exact thread, mounting hardware, and mechanical dimensions of the /016-100 variant before preparing the installation.

2. Air Gap Adjustment

The distance between the sensor tip and the target surface is an important installation parameter.

The PR6424 series has a nominal center air-gap value of approximately 2.7 mm. The actual setup must follow the applicable sensor and converter calibration requirements.

An incorrect air gap may cause the measurement signal to operate outside the intended linear range. During commissioning, verify the gap using the recommended installation procedure and compatible signal converter.

3. Target Material Compatibility

The sensor is designed for measurement against ferromagnetic materials, with 42CrMo4 steel used as the standard reference material in the published specifications.

Different target materials may produce different electrical responses. If the monitored shaft uses a different material, verify the calibration and compatibility requirements before installation.

4. Cable Routing

The sensor cable should be routed carefully to avoid mechanical damage, excessive bending, abrasion, and interference from high-power electrical conductors.

Follow the manufacturer’s minimum bending-radius requirements and cable protection recommendations. Avoid placing sensor cables alongside high-current motor cables where possible.

The exact cable length and connector configuration should be checked against the /016-100 product variant.

5. Signal Converter Connection

The PR6424 sensor requires a compatible signal converter as part of the measurement chain. The converter processes the sensor response and generates the corresponding measurement output.

The converter must match the sensor’s electrical characteristics and calibration requirements. Confirm connector compatibility, cable arrangement, supply requirements, and output configuration before connecting the system.

6. Commissioning and Verification

After installation, verify the sensor mounting, cable connections, initial air gap, and converter configuration.

Check that the measurement output responds correctly to changes in the sensor-to-target distance. Compare the resulting signal with the expected measurement range and confirm that the monitoring system receives a stable signal.

Record the installation position, calibration information, and relevant configuration details for future maintenance.

Compatible System Components

The PR6424/016-100 is normally used as part of a complete eddy current measurement chain. The following components may be involved in a typical installation.

A complete measurement system must be configured with compatible components. The sensor alone does not provide a complete monitoring or protection function.

Alternative Models and Replacement Considerations

The PR6424 belongs to a broader family of EPRO eddy current sensors. Related models may provide different sensing diameters, measurement ranges, and application characteristics.

When replacing a PR6424/016-100, compare the following details:

• Complete model number and suffix.
• Sensor head diameter.
• Probe body and mounting thread.
• Integrated cable length and cable type.
• Connector type and extension-cable arrangement.
• Sensitivity and linearity.
• Static and dynamic measurement ranges.
• Operating temperature requirements.
• Target material and shaft diameter.
• Signal-converter compatibility.
• Required certification and hazardous-area approvals.

A sensor from the same product family is not automatically a direct replacement. Differences in cable configuration, connector type, mechanical dimensions, or calibration can affect the measurement chain.

Key Advantages

Non-Contact Measurement

The eddy current principle allows shaft displacement and vibration to be measured without physical contact between the sensor and the rotating target.

16 mm Sensor Head

The 16 mm sensing head is designed for applications involving larger rotating shafts and suitable machinery-monitoring installations.

Static and Dynamic Measurement

The PR6424 series supports both static position measurement and dynamic vibration measurement, allowing one sensor type to provide information about different aspects of shaft movement.

High Measurement Sensitivity

The specified sensitivity of 4 V/mm and linearity of approximately ±1.5% support accurate displacement measurement when the complete sensor system is correctly installed and calibrated.

Industrial Machinery Applications

The series is designed for critical rotating equipment, including turbines, compressors, pumps, and fans.

Stainless Steel Construction

The stainless steel sensor sleeve provides a robust mechanical construction for suitable industrial installation environments.

PTFE Cable Material

The specified cable material is PTFE, selected for demanding industrial sensor applications. The actual temperature and environmental limits must be checked for the exact cable configuration.

Condition Monitoring Support

The sensor provides measurement information that can be used by compatible machinery monitoring systems to support equipment condition assessment and maintenance planning.

Technical FAQs

1. What is the Epro PR6424/016-100?

The Epro PR6424/016-100 is a 16 mm eddy current sensor designed for non-contact measurement of shaft displacement, vibration, position, and eccentricity in rotating machinery.

2. What is the sensor head diameter?

The sensor head diameter is 16 mm.

3. What is the measurement principle?

It uses eddy current technology. The sensor generates an electromagnetic field, and changes in the distance to a conductive target affect the electrical response of the sensing circuit.

4. What is the sensitivity of the PR6424 series?

The published sensitivity is 4 V/mm, equivalent to approximately 101.6 mV/mil, with a specified linearity of approximately ±1.5%.

5. What is its static measurement range?

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

6. Can it measure shaft vibration?

Yes. The series supports dynamic measurement from 0 to 1,000 μm peak-to-peak, making it suitable for appropriate shaft-vibration monitoring applications.

7. What material should be used as the measurement target?

The published standard target material is ferromagnetic steel, with 42CrMo4 used as the reference material. Other materials may require specific calibration considerations.

8. Does the sensor work independently?

No. It is normally used with a compatible signal converter and monitoring equipment. The complete measurement chain must be correctly configured.

9. Where is the PR6424/016-100 commonly used?

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

10. What is the weight of the sensor?

The supplied product weight is 0.2 kg. This is consistent with the published approximate weight of a PR6424 sensor with a 1 m cable and without armor.

11. Can another PR6424 variant replace the /016-100?

Not automatically. Check the exact cable length, connector, mounting dimensions, electrical configuration, and calibration requirements before selecting an alternative.

Procurement and Maintenance Recommendations

When purchasing the Epro PR6424/016-100, verify the complete model number and ensure that the sensor matches the existing machinery monitoring system.

For replacement applications, compare the probe diameter, mounting arrangement, cable configuration, connector, and compatible signal converter. These details are particularly important in turbine and compressor installations where the measurement chain may be calibrated as a complete system.

For used or surplus equipment, inspect the sensing tip, threaded body, cable insulation, connector, and identification label. Request clear product photographs and available test information. Confirm whether the quoted weight includes the cable, connector, and any protective armor.

During maintenance, inspect the sensor mounting for looseness and check the cable for cuts, abrasion, excessive bending, or connector damage. Verify the sensor gap and signal output according to the manufacturer’s procedures.

For critical machinery, retain installation records, calibration information, sensor location details, and converter settings. Consistent documentation makes it easier to compare vibration and displacement measurements over time and helps maintenance teams identify changes in machine behavior.

Conclusion

The Epro PR6424/016-100 16 mm Eddy Current Sensor is a non-contact measurement device designed for monitoring shaft vibration, displacement, position, and eccentricity in critical rotating machinery. Its 16 mm sensing head, 4 V/mm sensitivity, approximately ±1.5% linearity, and ±2.0 mm static measurement range make it suitable for a range of industrial machinery-monitoring applications.

Used with a compatible signal converter and monitoring system, the sensor can provide important measurement information for turbines, compressors, pumps, and fans. Before purchasing or replacing the PR6424/016-100, verify its complete configuration and compatibility with the existing measurement chain.