Product Overview

The Epro PR6424/010-110 16 mm Eddy Current Sensor is a non-contact displacement and vibration measurement device designed for industrial rotating machinery. It belongs to the PR6424 series of eddy current sensors, which are used in machinery monitoring systems to measure shaft vibration, axial and radial displacement, shaft position, eccentricity, and rotational speed reference signals.

Manufactured under the Epro product range associated with Emerson, the PR6424 series is designed for critical equipment such as steam turbines, gas turbines, hydro turbines, compressors, pumps, and industrial fans. These machines often operate continuously under demanding mechanical conditions, making accurate shaft-condition monitoring important for equipment protection and maintenance planning.

The PR6424/010-110 uses eddy current measurement technology. Unlike contact-based measuring devices, it detects the distance between the sensor tip and a conductive metal target without physically touching the rotating shaft. Changes in the distance between the probe and the target surface produce corresponding changes in the sensor’s electrical characteristics. When connected to a compatible signal converter, these changes can be processed into measurement signals for machinery monitoring systems.

The sensor has a 16 mm sensing head diameter and is designed for applications involving relatively large rotating shafts. Its measurement capabilities include static shaft position and dynamic shaft vibration. The PR6424 series has a nominal center air gap of approximately 2.7 mm and a sensitivity of 4 V/mm.

The PR6424/010-110 is suitable for applications where reliable non-contact measurement is required for machinery condition monitoring. When selecting this model, engineers should verify the complete ordering code, cable arrangement, connector configuration, and compatibility with the signal converter used in the existing measurement chain.

Technical Specifications

Note: Specifications can vary with sensor configuration and revision. The temperature range above follows the published PR6424 specification sheet. The supplied 0.2 kg weight is retained as the product listing value; the manufacturer’s approximate 200 g reference is for the sensor with 1 m cable without armor.

Function and Working Principle

The PR6424/010-110 operates using the eddy current principle. It generates a high-frequency electromagnetic field at the sensor tip and detects changes in that field when a conductive target approaches or moves away from the probe.

This measurement method allows the sensor to monitor shaft movement without physical contact, making it suitable for high-speed rotating machinery.

1. Electromagnetic Field Generation

The sensor contains an internal coil that generates an alternating electromagnetic field when connected to a compatible measurement system.

This field extends from the sensing tip toward the conductive target surface. When a metal shaft is positioned within the effective sensing range, the electromagnetic field interacts with the target material.

The characteristics of the generated field depend on the probe construction, connected electronics, target material, and sensor-to-target distance.

2. Eddy Current Formation

When the electromagnetic field reaches the conductive metal shaft, circulating electrical currents known as eddy currents are induced in the target surface.

These currents generate their own electromagnetic field, which interacts with the original field produced by the sensor.

As the distance between the probe and shaft changes, the induced eddy currents change accordingly. This affects the electrical characteristics of the sensor coil.

3. Displacement Measurement

The measurement system evaluates changes in the sensor signal to determine the distance between the probe and the target surface.

For the PR6424 series, the published sensitivity is 4 V/mm. Within the specified linear measurement range, changes in the sensor-to-target distance produce corresponding changes in the measurement signal.

This relationship allows the system to monitor both static and dynamic shaft movement.

Static measurements are useful for determining shaft position and axial displacement. Dynamic measurements are used to evaluate shaft vibration and other rapidly changing mechanical movements.

4. Signal Conditioning

The sensor is generally used as part of a complete measurement chain rather than as an independent monitoring instrument.

A typical system includes:

• PR6424 eddy current sensor.
• Compatible extension cable, where required by the configuration.
• Compatible signal converter.
• Machinery monitoring or protection system.

The signal converter conditions the sensor signal and provides an output suitable for monitoring equipment. The complete arrangement must be compatible in terms of electrical characteristics, cable configuration, sensitivity, and calibration.

5. Continuous Machinery Monitoring

Once installed and calibrated, the sensor can provide continuous shaft-condition information.

The monitoring system can use these measurements to identify abnormal shaft movement, changing vibration levels, and other mechanical conditions that may require investigation.

This information supports condition-based maintenance and machinery protection strategies.

Role in Industrial Machinery Monitoring Systems

The PR6424/010-110 is primarily used as a sensing component in industrial machinery monitoring systems. It provides measurement information that helps operators and maintenance engineers evaluate the condition of rotating equipment.

Shaft Vibration Monitoring

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

The PR6424 sensor measures shaft movement without physical contact, allowing the monitoring system to evaluate vibration behavior during operation.

Axial Displacement Monitoring

Axial shaft displacement refers to movement along the shaft’s longitudinal axis.

In turbines and compressors, excessive axial movement may indicate thrust-bearing problems or changes in the mechanical operating condition.

The PR6424 series can be applied to axial position measurement when installed in a suitable measurement arrangement.

Shaft Position Measurement

Static shaft position measurements help establish the relative position of the shaft within its mechanical assembly.

These measurements can provide useful information during startup, normal operation, shutdown, and maintenance inspections.

Eccentricity Measurement

Shaft eccentricity describes the deviation between the shaft’s geometric center and its actual rotational behavior.

Monitoring eccentricity can help identify mechanical conditions that affect shaft movement and rotating equipment stability.

Speed and Key Reference Detection

The PR6424 series can also be used in suitable configurations for speed and key reference measurements.

These signals can help monitoring systems establish rotational reference information for vibration analysis and machinery diagnostics.

Industrial Applications

The PR6424/010-110 is designed for demanding rotating machinery applications where non-contact measurement is required.

1. Steam Turbines

Steam turbines operate at high rotational speeds and are commonly used in power generation and industrial energy systems.

Shaft vibration and displacement monitoring are important for evaluating turbine mechanical conditions. The PR6424 series can measure radial and axial shaft movement when installed as part of a compatible monitoring system.

Typical monitoring objectives include:

• Radial shaft vibration measurement.
• Axial displacement monitoring.
• Shaft position measurement.
• Identification of abnormal vibration trends.
• Support for turbine protection systems.

2. Gas Turbines

Gas turbines are used in power generation, industrial processing, and mechanical drive applications.

Their rotating assemblies operate under high temperatures and mechanical loads. Continuous monitoring helps maintenance teams evaluate the condition of critical rotating components.

The PR6424 series can be used for non-contact shaft displacement and vibration measurement in appropriately designed gas turbine monitoring installations.

3. Hydro Turbines

Hydroelectric turbines operate under changing hydraulic and mechanical conditions.

Shaft vibration and position measurements can provide information about rotor behavior, mechanical stability, and changes in operating conditions.

The sensor can be incorporated into suitable hydro turbine monitoring systems to support continuous equipment assessment.

4. Industrial Compressors

Compressors are widely used in petrochemical plants, refineries, natural gas facilities, and manufacturing processes.

Large compressors often operate continuously, making shaft vibration monitoring an important part of preventive maintenance.

The PR6424 sensor can be used to monitor shaft displacement and vibration in compatible compressor measurement arrangements.

5. Industrial Pumps

Large industrial pumps are used in water treatment, chemical processing, power generation, and other industrial applications.

Monitoring shaft movement can help identify developing mechanical problems and support maintenance decisions.

The PR6424 series can be used where the shaft size, target material, operating environment, and measurement requirements are compatible with its specifications.

6. Industrial Fans

Large ventilation and process fans operate in power plants, manufacturing facilities, and industrial ventilation systems.

Non-contact shaft vibration monitoring can help identify abnormal mechanical behavior before it develops into more serious equipment problems.

The PR6424/010-110 may be considered for suitable large-shaft fan monitoring applications.

Installation and System Integration

Correct installation is essential for measurement accuracy and reliable long-term operation.

1. Verify the Sensor Configuration

Before installation, confirm that the sensor model is PR6424/010-110.

The complete ordering code should be checked against the existing measurement system. Different PR6424 variants may have different cable lengths, armor arrangements, connector configurations, or other mechanical details.

Do not assume that sensors from the same series are interchangeable without checking their complete specifications.

2. Check the Target Material

The PR6424 series is designed to measure compatible ferromagnetic targets.

The published standard target material is 42CrMo4 steel. Using a different target material may affect measurement characteristics and calibration.

The target surface should also be suitable for the intended measurement. Surface condition, geometry, and installation position can influence measurement quality.

3. Observe the Required Air Gap

The published nominal center air gap is approximately 2.7 mm.

During installation, the sensor must be positioned within the specified measurement range. Incorrect probe positioning may reduce measurement accuracy or cause the signal to operate outside its linear region.

The actual installation gap should follow the manufacturer’s calibration and setup instructions.

4. Secure the Sensor Mechanically

The sensor should be mounted securely using the appropriate mechanical arrangement.

Loose mounting can introduce unwanted movement and measurement errors. The probe should be positioned so that it does not contact the rotating shaft during normal operation.

Installation should account for thermal expansion, shaft movement, machine vibration, and maintenance access.

5. Connect the Measurement Chain

The PR6424 sensor must be connected to compatible measurement electronics.

Depending on the ordered configuration, the measurement chain may include an extension cable and a signal converter. Verify cable type, connector arrangement, total cable length, and converter compatibility.

Incorrect combinations may cause measurement errors or prevent the monitoring system from operating correctly.

6. Calibrate and Verify the Signal

After installation, the complete measurement chain should be calibrated and checked.

The commissioning process should verify:

• Sensor identification and wiring.
• Probe-to-target gap.
• Signal sensitivity.
• Measurement linearity.
• Static shaft position.
• Dynamic measurement response.
• Monitoring system channel configuration.

Calibration should follow the manufacturer’s instructions and the requirements of the machinery monitoring system.

Compatible System Components

The PR6424/010-110 is normally used with other components to form a complete machinery measurement chain.

A complete measurement chain requires compatible components. The sensor alone should not be assumed to provide a directly usable PLC or DCS signal without the appropriate signal-conditioning equipment.

Alternative Models and Replacement Considerations

The PR6424 series includes multiple sensor configurations. When selecting a replacement, the complete model number should be compared rather than relying only on the 16 mm sensor diameter.

These products should not be treated as direct plug-and-play replacements. Differences in sensitivity, linear range, target requirements, cable arrangements, and signal-conditioning electronics can affect measurement accuracy.

Before replacing the PR6424/010-110, verify the following:

• Sensor head diameter.
• Complete model and ordering suffix.
• Thread and mounting arrangement.
• Probe cable configuration.
• Extension cable length.
• Signal converter compatibility.
• Sensitivity and calibration requirements.
• Target material and shaft diameter.
• Operating temperature and environmental conditions.

Key Advantages

Non-Contact Measurement

The PR6424 sensor measures shaft movement without physically contacting the rotating surface. This reduces mechanical wear at the sensing point and supports continuous measurement.

High Measurement Sensitivity

The published sensitivity of 4 V/mm allows the measurement system to detect relatively small changes in sensor-to-target distance.

Static and Dynamic Measurement

The sensor supports both static shaft position measurement and dynamic vibration measurement, making it useful for multiple machinery monitoring tasks.

Suitable for Critical Rotating Machinery

The PR6424 series is designed for applications involving turbines, compressors, pumps, and fans where reliable shaft-condition information is important.

Stable Measurement Characteristics

The published long-term drift specification is less than 0.3%, supporting stable measurement performance under suitable operating and installation conditions.

Industrial Environmental Capability

The stainless steel sleeve and PTFE cable construction are intended for demanding industrial measurement environments. Actual operating limits must be observed during installation.

Integration with Machinery Monitoring Systems

When paired with compatible extension cables and signal converters, the sensor can form part of a continuous machinery condition-monitoring and protection system.

Technical FAQs

1. What is the Epro PR6424/010-110?

The Epro PR6424/010-110 is a 16 mm eddy current sensor designed for non-contact measurement of shaft displacement, vibration, position, and other rotating machinery parameters.

2. What is the sensor head diameter?

The sensor head diameter is 16 mm.

3. What is the measurement principle?

It operates using electromagnetic induction. The sensor generates an electromagnetic field, and changes in the distance to a conductive target affect the eddy currents and electrical characteristics of the sensor.

4. What is the sensitivity of the PR6424 series?

The published sensitivity is 4 V/mm, equivalent to approximately 101.6 mV/mil.

5. What is its static measurement range?

The published static measurement range is ±2.0 mm.

6. What is the nominal air gap?

The nominal center air gap is approximately 2.7 mm. Correct positioning is important for maintaining measurement linearity.

7. What materials can the sensor measure?

The PR6424 series is designed for ferromagnetic targets. The published standard target material is 42CrMo4 steel.

8. What equipment can use this sensor?

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

9. Can the PR6424/010-110 connect directly to a PLC?

The sensor is normally used with compatible signal-conditioning electronics. A suitable converter or monitoring module is required to provide the appropriate signal interface for a PLC or DCS.

10. What is the weight of the sensor?

The supplied product listing weight is 0.2 kg. The manufacturer specifies approximately 200 g for the sensor with 1 m cable without armor.

11. Why is the cable configuration important?

Cable length, connector type, and cable construction affect compatibility with the signal converter and measurement chain. Replacement sensors should match the original system configuration.

12. What should be checked before purchasing a replacement?

Verify the complete model number, sensor diameter, cable arrangement, connector type, sensitivity, target material, and compatibility with the existing converter.

Procurement and Maintenance Recommendations

When purchasing the Epro PR6424/010-110, confirm the exact model number and configuration before placing an order. The PR6424 series includes multiple variants, and differences in cable length, armor, connector, and mechanical design may affect compatibility.

For replacement projects, compare the new sensor with the existing unit and review the connected extension cable and signal converter. Confirm that the complete measurement chain supports the required sensitivity and calibration characteristics.

For used or surplus equipment, request clear photographs of the product label, probe body, cable, and connector. Check for damaged cable insulation, bent connectors, corrosion, and visible mechanical damage.

During maintenance, inspect the mounting arrangement and ensure that the probe remains securely positioned. Verify the air gap, cable condition, signal stability, and measurement channel calibration according to the machinery manufacturer’s maintenance procedures.

For critical turbine and compressor applications, sensor replacement should be followed by appropriate calibration and functional testing. This helps ensure that the monitoring system continues to provide reliable information for equipment protection and condition assessment.

Conclusion

The Epro PR6424/010-110 16 mm Eddy Current Sensor is an industrial non-contact measurement device designed for monitoring shaft displacement, vibration, position, and related parameters in rotating machinery.

With a 16 mm sensing head, 4 V/mm sensitivity, ±2.0 mm static measurement range, and approximately 2.7 mm nominal center air gap, it is designed for use in demanding machinery monitoring applications.

When integrated with compatible extension cables, signal converters, and monitoring equipment, the PR6424/010-110 can support continuous condition monitoring of turbines, compressors, pumps, and industrial fans. Accurate model identification, correct installation, and proper calibration are essential for reliable measurement performance.