Product Overview

The Epro PR6424/019-100 16 mm Eddy Current Sensor is a non-contact displacement sensor designed for monitoring the condition and operating behavior of rotating industrial machinery. It belongs to the PR6424 sensor family associated with Emerson EPRO machinery protection and condition-monitoring systems.

The sensor uses eddy current technology to measure the distance between its sensing tip and a conductive metallic target. When installed near a rotating shaft, it can detect changes in the gap between the probe and the shaft surface. These changes can be used to monitor shaft vibration, radial and axial displacement, position, eccentricity, and other machine operating characteristics.

With a nominal sensor head diameter of 16 mm, the PR6424 series is intended for applications involving relatively large rotating shafts. It is commonly associated with critical machinery such as steam turbines, gas turbines, hydro turbines, compressors, pumps, and industrial fans.

The PR6424/019-100 is intended to operate as part of a compatible measurement chain rather than as a standalone monitoring instrument. The sensor works with an appropriate signal converter and monitoring equipment to transform the measured displacement into a usable electrical signal.

This type of measurement is important in industrial facilities where changes in shaft vibration or position may indicate bearing wear, rotor imbalance, misalignment, or other developing mechanical problems. Continuous monitoring helps maintenance personnel evaluate machine condition and identify abnormal operating trends.

Technical Specifications

Note: The technical values above describe the PR6424 sensor family. Confirm the exact cable, connector, mounting, and environmental configuration of the PR6424/019-100 against its product label and applicable documentation.

Function and Working Principle

The PR6424/019-100 operates using the eddy current measurement principle. It measures the distance between the sensor tip and a conductive metallic target without requiring physical contact.

1. Generation of an Electromagnetic Field

The sensor contains an electrical coil inside its probe head. When supplied with the appropriate excitation signal from a compatible converter, the coil generates a high-frequency electromagnetic field around the sensing tip.

This field extends toward the nearby metallic target, typically a ferromagnetic steel shaft.

2. Eddy Current Formation

When the electromagnetic field reaches the conductive shaft surface, it induces small circulating electrical currents known as eddy currents.

These currents affect the electromagnetic characteristics of the sensor coil. The effect changes according to the distance between the probe tip and the target surface.

As the shaft moves closer to or farther away from the sensor, the electrical characteristics of the sensing circuit change correspondingly.

3. Signal Conversion

The sensor’s electrical response is processed by a compatible signal converter. The converter transforms the measurement into an output signal that represents the distance between the probe and the target.

For the PR6424 family, the documented sensitivity is 4 V/mm, with a typical linearity of ±1.5%. These characteristics allow small changes in shaft position to be detected and evaluated by the associated monitoring system.

4. Static Displacement Measurement

Static displacement measurement is used to determine the relative position of a shaft or other metallic target.

For example, a monitoring system may use the sensor to observe changes in shaft position during machine startup, normal operation, or shutdown. These measurements can help identify abnormal positioning or changes in machine clearances.

5. Dynamic Vibration Measurement

Dynamic measurement focuses on rapid changes in the distance between the sensor and the rotating shaft.

As the shaft vibrates, the probe detects corresponding changes in the measurement gap. The monitoring system can use this information to evaluate vibration amplitude and operating trends.

This function is particularly important in large rotating machines where excessive vibration may affect bearing performance, mechanical stability, and equipment service life.

Role in Industrial Machinery Protection Systems

The Epro PR6424/019-100 can serve as a sensing component in a machinery condition-monitoring and protection architecture.

It is generally installed near a rotating shaft and connected to compatible signal-conditioning and monitoring equipment. The resulting measurement data can be used by maintenance personnel and control-room operators to evaluate machine condition.

Shaft Vibration Monitoring

Shaft vibration is an important indicator of rotating machinery condition. Changes in vibration amplitude or operating patterns may be associated with rotor imbalance, misalignment, bearing problems, looseness, or other mechanical conditions.

The PR6424 sensor detects shaft movement without contacting the rotating surface. This makes it suitable for continuous monitoring applications where direct mechanical contact would be impractical.

Shaft Position Monitoring

The sensor can measure the relative position of a shaft against a fixed reference point. This is useful when evaluating axial or radial movement in large rotating machinery.

Position measurements can help engineers understand changes in machine clearances and identify abnormal shaft movement.

Eccentricity Measurement

Eccentricity describes the deviation of a rotating shaft from its ideal geometric center. Excessive eccentricity can contribute to vibration and uneven mechanical loading.

A correctly installed eddy current sensor can provide measurement data that helps identify changes in shaft geometry or rotation behavior.

Integration with Monitoring Equipment

The sensor normally operates with a compatible EPRO signal converter and machinery monitoring system. The converter provides the required excitation and processes the probe signal.

The complete measurement chain must be matched according to sensor type, cable configuration, converter characteristics, and monitoring-system requirements.

Industrial Applications

The PR6424 series is designed for critical rotating machinery applications. Its non-contact measurement principle is particularly useful in facilities where reliable shaft monitoring is important for equipment protection and maintenance planning.

1. Steam Turbines

Steam turbines are used in power generation and industrial steam systems. Their rotors operate at high speeds and require continuous monitoring of vibration and shaft position.

The PR6424 sensor can be installed at suitable measurement locations to detect changes in shaft displacement. Monitoring data can help maintenance teams evaluate rotor behavior and investigate abnormal vibration conditions.

2. Gas Turbines

Gas turbines are used in power plants, oil and gas facilities, and industrial energy systems. Their rotating assemblies operate under demanding mechanical and thermal conditions.

Non-contact shaft monitoring provides information about rotor vibration and displacement without introducing physical contact with the rotating surface.

3. Hydro Turbines

Hydroelectric generating equipment often operates continuously for long periods. Monitoring shaft movement and vibration can help identify mechanical changes before they develop into serious operating problems.

The PR6424 series can be considered for suitable hydro-turbine monitoring arrangements where its measurement range and installation requirements match the application.

4. Industrial Compressors

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

Shaft vibration and displacement measurements help engineers evaluate rotor stability and investigate changes in machine behavior. Eddy current sensors are commonly used in these applications because they can measure shaft movement without physical contact.

5. Pumps and Fans

Industrial pumps and fans may operate continuously in production and utility systems. Changes in shaft vibration can be associated with bearing wear, imbalance, misalignment, or mechanical looseness.

A suitable PR6424 installation can provide measurement information for condition-monitoring systems and maintenance programs.

6. Industrial Machinery Condition Monitoring

In facilities with centralized machinery monitoring, displacement sensors can supply measurement data to monitoring equipment for evaluation and alarm management.

The sensor can therefore form part of a broader predictive-maintenance strategy designed to improve equipment availability and support maintenance decisions.

Installation and System Integration

Correct installation is essential for obtaining reliable measurement results. Probe positioning, target material, mounting stability, cable routing, and converter compatibility all influence the performance of an eddy current measurement system.

1. Select the Correct Measurement Location

Identify a suitable measurement point on the rotating shaft before installing the sensor.

The mounting position should provide a stable reference and an appropriate clearance between the sensing tip and the shaft surface. Avoid locations where the probe may be exposed to unnecessary mechanical impact, excessive vibration of the mounting structure, or interference from nearby metallic components.

The sensor must be positioned according to the machinery manufacturer’s measurement and installation requirements.

2. Verify the Target Material

The PR6424 family is specified for measurement against ferromagnetic steel, with 42CrMo4 commonly used as the reference material in published specifications.

Target material affects sensor calibration and measurement characteristics. If the shaft material differs from the reference material, the measurement system’s compatibility and calibration requirements should be reviewed.

3. Set the Correct Air Gap

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

The PR6424 family has a nominal center air gap of approximately 2.7 mm. The actual setting should follow the applicable sensor and converter instructions.

An incorrect air gap may reduce measurement accuracy or cause the system to operate outside its specified linear range.

4. Secure the Sensor Mounting

The sensor should be mounted securely using the correct mechanical arrangement. Loose mounting hardware or vibration of the mounting bracket can introduce unwanted measurement errors.

Where threaded mounting is used, verify the exact thread specification of the PR6424/019-100 before installation. Do not assume that every PR6424 variant has identical mechanical details.

5. Check Cable Routing

The sensor cable carries the measurement signal between the probe and the compatible converter.

Route the cable carefully to prevent mechanical damage, excessive bending, abrasion, and unnecessary exposure to high temperatures. Maintain the minimum bending radius specified for the actual cable configuration.

Avoid routing sensitive sensor cables alongside high-current power cables where this could introduce electrical interference.

6. Connect a Compatible Signal Converter

The PR6424 sensor must be matched with an appropriate EPRO signal converter. The converter provides the required excitation and processes the sensor response.

Before connecting the equipment, verify the sensor model, cable and connector arrangement, converter type, and system calibration requirements.

7. Perform Commissioning Checks

After installation, inspect the mechanical mounting, cable condition, connectors, and converter connections.

Verify the initial measurement gap and confirm that the monitoring system displays a stable measurement under the expected operating conditions.

Where required, check sensor calibration, signal output, alarm settings, and measurement-channel configuration before returning the machine to normal operation.

Compatible System Components

The PR6424/019-100 is normally used as part of a complete machinery measurement chain. The following components represent common system elements that may be required, depending on the monitoring architecture.

The table identifies potential system components, not a guaranteed accessory package. Actual compatibility must be confirmed using the exact sensor and converter documentation.

Alternative Models and Replacement Considerations

The PR6424 belongs to a wider EPRO eddy current sensor family. Other models may provide different measuring ranges, sensitivity values, temperature capabilities, or mechanical configurations.

Before replacing a PR6424/019-100, compare:

• Complete model and variant number.
• Sensor head diameter.
• Static and dynamic measuring ranges.
• Sensitivity and linearity.
• Nominal air gap.
• Target shaft material.
• Cable length and cable construction.
• Connector and adaptor arrangement.
• Mounting thread and mechanical dimensions.
• Operating temperature and environmental limits.
• Compatible signal converter and monitoring system.

A sensor with the same nominal diameter may not provide identical electrical or mechanical performance. Replacement selection should be based on the complete measurement-chain requirements.

Key Advantages

Non-Contact Measurement

The eddy current principle allows the sensor to measure shaft movement without touching the rotating surface. This is suitable for continuous monitoring of high-speed machinery.

16 mm Sensor Head

The 16 mm probe diameter supports applications involving larger rotating shafts and critical turbomachinery.

Static and Dynamic Measurement

The PR6424 family supports both static displacement measurement and dynamic vibration measurement, allowing one sensor type to contribute to different machinery-monitoring functions.

High Measurement Sensitivity

The documented family sensitivity of 4 V/mm enables the system to detect small changes in the distance between the probe and the target.

Industrial Machinery Applications

The sensor family is designed for use in turbines, compressors, pumps, fans, and other rotating machinery.

Integration with EPRO Monitoring Equipment

When paired with a compatible signal converter, the sensor can form part of an established machinery condition-monitoring system.

Support for Predictive Maintenance

Continuous measurement data can help maintenance teams observe operating trends, investigate abnormal behavior, and plan equipment inspections.

Technical FAQs

1. What is the Epro PR6424/019-100?

The Epro PR6424/019-100 is a 16 mm eddy current sensor used for non-contact measurement of shaft displacement and vibration in rotating machinery.

2. What is the sensor head diameter?

The specified sensor head diameter is 16 mm.

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

The published PR6424 family specification gives a static measurement range of ±2.0 mm and a dynamic measurement range of 0–1,000 μm peak-to-peak.

4. What is the sensitivity of the PR6424 sensor?

The documented family sensitivity is 4 V/mm, with typical linearity of ±1.5%.

5. What is the operating principle?

The sensor generates an electromagnetic field at its probe tip. When the field interacts with a conductive metallic target, eddy currents are induced. Changes in the distance between the probe and target affect the sensor response, allowing displacement to be measured.

6. What materials can the sensor measure?

The published PR6424 specifications use ferromagnetic steel as the reference target material, with 42CrMo4 as the standard reference material. Other materials may require specific compatibility and calibration checks.

7. Does the PR6424/019-100 work without a signal converter?

It is intended to operate as part of a compatible measurement chain. A suitable signal converter is required to provide excitation and process the sensor signal.

8. Where is this sensor commonly used?

Typical applications include steam turbines, gas turbines, hydro turbines, compressors, pumps, fans, and other critical rotating machinery.

9. What is the weight of the sensor?

The supplied product weight is 0.2 kg. Published PR6424 family documentation also gives an approximate weight of 200 g for the sensor with a 1-meter cable and without armor.

10. Can another PR6424 variant replace the PR6424/019-100?

Not automatically. Different variants may have different cable lengths, connector arrangements, mounting details, and other configuration characteristics. Compare the complete model number and technical documentation before substitution.

Procurement and Maintenance Recommendations

When purchasing the Epro PR6424/019-100, verify the complete part number on the product label. The PR6424 family includes multiple variants, and the suffix can identify important differences in cable and connection arrangements.

Ask suppliers to confirm the sensor head diameter, cable configuration, connector type, mounting details, and product condition. For replacement projects, compare the existing sensor with the proposed unit and verify compatibility with the installed converter.

For used or refurbished sensors, inspect the probe body, sensing tip, cable insulation, connectors, and identification label. Where possible, request test information or a suitable functional verification before installation.

During maintenance, keep the probe and mounting area clean, inspect the cable for damage, and check the mechanical fixing periodically. Changes in the measurement signal should be evaluated together with operating conditions and other machinery-monitoring data.

The signal converter and monitoring channel should also be checked as part of troubleshooting. A measurement abnormality may result from the probe, cable, converter, installation gap, target surface, or monitoring configuration.

Conclusion

The Epro PR6424/019-100 16 mm Eddy Current Sensor is designed for non-contact measurement of shaft displacement and vibration in critical rotating machinery. Its PR6424 family specifications include a 16 mm sensing head, ±2.0 mm static measuring range, 4 V/mm sensitivity, and ±1.5% linearity.

When used with a compatible signal converter and monitoring system, the sensor can support machinery condition monitoring in turbines, compressors, pumps, fans, and other industrial rotating equipment.

For procurement and replacement applications, verifying the complete variant number, cable configuration, connector arrangement, and converter compatibility is essential to maintaining reliable measurement performance.