Product Overview

The EPRO PR6424/014-101 16 mm Eddy Current Sensor is a non-contact displacement sensor designed for monitoring the condition and operating behavior of rotating machinery. It belongs to the PR6424 sensor family developed for critical turbomachinery applications, including steam turbines, gas turbines, compressors, pumps, generators, and industrial fans.

Manufactured under the EPRO product line of Emerson, the PR6424 series uses eddy current measurement technology to detect the distance between the sensor tip and a conductive target. In machinery-monitoring applications, the target is commonly a ferromagnetic steel shaft. As the shaft moves or vibrates, the distance between the probe and the shaft surface changes. The sensor detects these changes and provides a measurement signal for a compatible signal converter or machinery protection system.

The PR6424/014-101 has a nominal sensor head diameter of 16 mm and is intended for applications requiring accurate monitoring of shaft displacement and vibration. It can support measurements associated with radial and axial shaft movement, shaft position, eccentricity, and rotational speed-related monitoring arrangements.

Unlike contact-based measurement devices, an eddy current sensor does not need to physically touch the rotating shaft. This makes it suitable for continuous monitoring of high-speed machinery, where mechanical contact could cause wear or interfere with normal operation.

The sensor is generally used as part of a complete measurement chain consisting of a probe, suitable extension cable where required, and a compatible signal converter or monitoring instrument. Correct component matching is essential for obtaining accurate measurement results.

Technical Specifications

Note: The specifications above describe the PR6424 sensor family and the supplied product information. Exact cable length, connector arrangement, thread configuration, and operating temperature limits should be verified against the PR6424/014-101 product documentation and nameplate.

Function and Working Principle

The PR6424/014-101 operates according to the eddy current principle. It generates an electromagnetic field near the sensor tip and measures changes caused by the presence and movement of a conductive target.

When the sensor is installed close to a rotating shaft, the gap between the probe tip and the shaft becomes the primary measurement variable. Changes in this gap affect the sensor’s electrical characteristics, allowing the associated measurement system to determine shaft displacement.

1. Non-Contact Displacement Measurement

The sensor measures the distance between its sensing tip and the target surface without direct physical contact.

When the shaft moves closer to the probe, the measured gap decreases. When the shaft moves away, the gap increases. These changes can be converted into displacement information by a compatible signal converter.

This measurement method is particularly useful for rotating equipment because the probe can monitor shaft movement continuously without contacting the moving surface.

2. Eddy Current Measurement Principle

The probe contains an electrical coil that generates a high-frequency electromagnetic field. When a conductive metal target enters this field, eddy currents are induced in the target material.

The induced currents influence the electromagnetic characteristics of the probe coil. The resulting change is related to the distance between the sensor and the target.

A compatible converter processes this change and produces a usable measurement signal. The output can then be transmitted to a machinery-monitoring instrument, protection system, or diagnostic platform.

3. Shaft Vibration Monitoring

Rotating machinery may experience vibration because of rotor imbalance, shaft misalignment, bearing deterioration, mechanical looseness, or other operating conditions.

When the shaft vibrates relative to the sensor, the probe detects changes in the distance between the shaft surface and the sensing tip.

The measurement system can use this information to evaluate shaft vibration behavior. Maintenance personnel can analyze the data to identify abnormal trends and investigate possible mechanical problems.

4. Shaft Position Measurement

The sensor can also measure static shaft position within its calibrated operating range.

This information is useful for monitoring rotor movement, shaft displacement, and changes in mechanical alignment. In suitable machinery installations, position measurements can help identify operating conditions that require further inspection.

5. Eccentricity and Speed-Related Monitoring

The PR6424 family is designed for measurement applications that include shaft eccentricity and speed/key-related monitoring arrangements.

For speed-related applications, the sensor detects changes associated with the rotating target surface. The monitoring system processes the resulting signal to determine the relevant rotational information.

The exact measurement arrangement depends on the target geometry, probe positioning, signal converter, and monitoring equipment.

Role in Industrial Machinery Protection Systems

The PR6424/014-101 is commonly used as a sensing element within a larger machinery-monitoring system. It does not normally function as a complete protection system by itself. Instead, it provides measurement information to compatible electronic equipment.

1. Integration with Signal Converters

The sensor must be paired with a compatible signal converter. The converter processes the probe’s electrical response and generates an output suitable for monitoring instruments or control systems.

Emerson EPRO equipment includes different converter configurations, such as CON011, CON021, CON031, and CON041 families. Compatibility must be confirmed according to the exact probe version, cable arrangement, and converter requirements.

The probe, extension cable, and converter should be treated as a matched measurement system. Using incompatible components can result in incorrect calibration or unreliable readings.

2. Integration with Machinery Monitoring Systems

After signal conversion, measurement data can be supplied to a machinery-monitoring platform.

Depending on the system architecture, the information may be used for:

• Continuous shaft displacement monitoring.
• Radial shaft vibration measurement.
• Axial shaft position monitoring.
• Eccentricity measurement.
• Speed-related monitoring.
• Machinery condition assessment.
• Alarm and protection functions.

The monitoring system determines how measurements are displayed, recorded, evaluated, and used for alarm or shutdown decisions.

3. Predictive Maintenance

Continuous measurement allows maintenance teams to observe changes in machine behavior over time.

For example, a gradual increase in shaft vibration may indicate developing mechanical deterioration. A change in shaft position may also justify investigation of bearing conditions, thermal expansion, or rotor alignment.

The sensor provides measurement data that can support predictive maintenance strategies. However, diagnosing a mechanical fault requires analysis of the complete measurement system and other relevant operating information.

Industrial Applications

The EPRO PR6424/014-101 is designed for critical rotating machinery where reliable shaft displacement and vibration measurements are important.

1. Steam Turbines

Steam turbines operate under demanding mechanical and thermal conditions. Shaft vibration and displacement measurements help operators monitor rotor behavior during startup, normal operation, and shutdown.

A PR6424 sensor installed at an appropriate measurement location can provide shaft movement information to a compatible turbine monitoring system.

2. Gas Turbines

Gas turbines contain high-speed rotating assemblies that require continuous condition monitoring. Changes in shaft vibration or position may indicate mechanical conditions that require investigation.

The PR6424 series can be used as part of a suitable monitoring arrangement for measuring shaft movement in these installations.

3. Industrial Compressors

Compressors are widely used in chemical processing, petrochemical facilities, natural gas operations, and general manufacturing.

Shaft displacement and vibration measurements can help maintenance teams evaluate rotor behavior and identify changes that may be associated with imbalance, misalignment, bearing wear, or other mechanical issues.

4. Pumps

Large industrial pumps may operate continuously in water treatment, power generation, chemical production, and process industries.

Non-contact shaft measurement helps monitor rotating components without introducing physical contact between the probe and the shaft.

The sensor can support monitoring arrangements for pumps where the shaft diameter, installation space, target material, and measurement requirements are compatible.

5. Generators

Generators contain rotating assemblies whose mechanical condition is important for reliable power production.

Shaft displacement and vibration information can be used by monitoring systems to evaluate rotor movement and identify abnormal operating trends.

6. Industrial Fans

Large industrial fans are used in ventilation systems, power plants, cement facilities, and process installations.

The PR6424 sensor family can be considered for suitable rotating equipment monitoring applications where non-contact shaft displacement measurement is required.

Installation and System Integration

Correct installation is essential for measurement accuracy, reliable signal transmission, and long-term sensor performance.

1. Confirm the Sensor Model

Before installation, verify the complete model number PR6424/014-101. The PR6424 family includes different probe configurations, cable arrangements, connector options, and mounting specifications.

A sensor with the same 16 mm head diameter is not necessarily interchangeable with another PR6424 model.

Check the nameplate, product documentation, cable configuration, and connector arrangement before replacement.

2. Select the Correct Mounting Position

The probe should be installed at the measurement location specified by the machinery design.

The sensor tip must face the intended target surface with the required clearance. The mounting arrangement should provide adequate mechanical stability and prevent unwanted movement during equipment operation.

The installation must also maintain the required clearance from surrounding ferromagnetic materials, which could influence the electromagnetic measurement field.

3. Set the Correct Air Gap

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

The actual installation gap must be established using the applicable sensor and converter documentation. Incorrect gap adjustment can reduce the usable measurement range or result in an inaccurate output.

The gap should be checked during commissioning and documented for future maintenance.

4. Check the Target Material

Eddy current sensor performance depends on the electrical and magnetic properties of the target material.

The PR6424 specification identifies ferromagnetic steel as the reference target material. The target surface and material should be consistent with the manufacturer’s calibration requirements.

Differences in material composition, surface condition, or target geometry may affect measurement accuracy.

5. Cable Routing and Protection

The sensor cable should be routed to avoid unnecessary mechanical stress, sharp bends, abrasion, and exposure to unsuitable temperatures.

The PR6424 documentation identifies PTFE cable insulation and specifies minimum bending radii that depend on whether the cable is armored or non-armored.

Keep the cable away from sources of excessive electrical interference where possible. Use the specified connector and extension cable arrangement for the selected converter.

6. Connect to a Compatible Converter

Connect the sensor to the designated signal converter using the correct cable and connector configuration.

Before energizing the monitoring system, verify the sensor model, cable length, connector condition, and converter compatibility.

A mismatched probe and converter can produce incorrect measurement values even if the sensor itself is functioning normally.

7. Commissioning and Signal Verification

After installation, check the probe gap, cable condition, connector seating, and converter settings.

Verify that the output changes consistently with the target distance and that the monitoring system displays plausible values.

Record the installation gap, calibration information, and relevant system settings for future maintenance.

Compatible System Components

The PR6424/014-101 is generally used with additional equipment to create a complete measurement and monitoring system.

The listed converters are examples from the wider EPRO system family. They should not be assumed to be interchangeable with every PR6424/014-101 configuration without checking the applicable compatibility documentation.

Alternative Models and Replacement Considerations

The PR6424 series includes different sensor configurations. When replacing the PR6424/014-101, the replacement should be selected according to its mechanical and electrical characteristics.

Before selecting an alternative, compare:

• Complete sensor model number.
• Sensor head diameter and mechanical dimensions.
• Mounting thread and installation length.
• Cable length and cable construction.
• Connector type and pin configuration.
• Probe-to-converter compatibility.
• Sensitivity and linear measurement range.
• Target material and shaft diameter.
• Operating temperature requirements.
• Monitoring system input and calibration settings.

A replacement probe should not be selected based only on the 16 mm head diameter. The full model suffix and electrical configuration are essential for maintaining measurement accuracy.

Key Advantages

Non-Contact Measurement

The sensor measures shaft displacement without physically touching the rotating target. This supports continuous monitoring without introducing contact-related wear.

Designed for Critical Rotating Machinery

The PR6424 family is intended for applications involving turbines, compressors, pumps, fans, and other rotating equipment where shaft movement is an important operating parameter.

High Measurement Sensitivity

The family specification identifies a sensitivity of 4 V/mm, supporting measurement of relatively small changes in the sensor-to-target distance.

Static and Dynamic Measurement Capability

The sensor family supports static displacement measurement and dynamic shaft movement monitoring within its specified measurement range.

Industrial Sensor Construction

The stainless-steel sleeve and PTFE cable construction are designed for industrial sensor installations. Actual environmental suitability depends on the specific probe configuration and installation conditions.

Integration with EPRO Monitoring Equipment

The sensor can be incorporated into compatible EPRO measurement systems using the appropriate extension cable and signal converter.

Support for Condition-Based Maintenance

Continuous measurement data can help maintenance teams identify abnormal changes in shaft position or vibration and investigate developing machinery problems.

Technical FAQs

1. What is the EPRO PR6424/014-101?

The EPRO PR6424/014-101 is a 16 mm eddy current displacement sensor designed for non-contact measurement of shaft movement in rotating machinery.

2. What is the sensor head diameter?

The sensor head diameter is 16 mm, as specified in the product description.

3. What is the measuring principle?

It uses eddy current technology. The sensor generates an electromagnetic field, and changes in the conductive target’s distance influence the probe’s electrical characteristics.

4. What is the typical sensitivity of the PR6424 series?

The published family specification identifies a sensitivity of 4 V/mm, with linearity of no more than ±1.5%.

5. What is the static measurement range?

The PR6424 family specification lists a static measuring range of ±2.0 mm. The usable range of a specific installation depends on calibration and the associated converter.

6. What is the nominal air gap?

The published nominal center air gap is approximately 2.7 mm. The actual installation setting should follow the applicable product documentation.

7. Which materials can be measured?

The published reference target is ferromagnetic steel. Target material and surface characteristics should be checked against the manufacturer’s calibration requirements.

8. Where is the PR6424/014-101 commonly used?

It is intended for suitable rotating machinery applications, including steam turbines, gas turbines, compressors, pumps, generators, and fans.

9. Does the sensor work without a signal converter?

The probe is normally part of a measurement chain that includes a compatible signal converter. The converter processes the probe signal for use by monitoring equipment.

10. What should be checked before replacing the sensor?

Verify the complete model number, sensor dimensions, mounting thread, cable length, connector arrangement, converter compatibility, target material, and calibration requirements.

11. What is the weight of the PR6424/014-101?

The supplied product weight is 0.2 kg. This is consistent with the PR6424 family specification of approximately 200 grams for the sensor with a 1 m cable and without armor.

12. What operating temperature should be used for selection?

Temperature limits must be checked against the current installation documentation and exact sensor configuration. Different published documents may show different limits, so an older family datasheet should not automatically override the current product-specific installation requirements.

Procurement and Maintenance Recommendations

When purchasing the EPRO PR6424/014-101, verify the complete catalog number rather than relying only on the PR6424 family name or the 16 mm sensor diameter.

Confirm the sensor’s physical configuration, cable length, connector type, mounting thread, and compatibility with the existing signal converter. These details are particularly important when sourcing replacement probes for operating turbines, compressors, pumps, and generators.

For used or refurbished sensors, request clear photographs of the probe head, threaded mounting section, cable, connector, and identification label. Inspect the sensing tip for physical damage and check the cable for cuts, crushing, abrasion, or signs of excessive heat exposure.

During maintenance, verify the mounting stability and probe gap. Inspect cable routing and connector condition, and compare measurement signals with established operating baselines. Unexpected changes in shaft displacement or vibration should be investigated using the complete machinery-monitoring system rather than attributing the condition to the sensor alone.

For critical machinery, maintain records of the sensor model, installation position, converter configuration, calibration information, and replacement history. This documentation can simplify future troubleshooting and help prevent incompatible spare parts from being installed.

Conclusion

The EPRO PR6424/014-101 16 mm Eddy Current Sensor is designed for non-contact shaft displacement and vibration measurement in critical rotating machinery. Its eddy current operating principle allows it to monitor changes in the distance between the probe and a conductive shaft without direct physical contact.

With a 16 mm sensor head and a supplied weight of 0.2 kg, the probe is intended for integration into compatible EPRO measurement and machinery-monitoring systems. The PR6424 family offers a nominal sensitivity of 4 V/mm and a static measuring range of ±2.0 mm, subject to the selected configuration and calibration.

For maintenance and replacement projects, confirming the complete model number, cable arrangement, converter compatibility, mounting dimensions, and current operating limits is essential. Correct component matching and installation help maintain reliable shaft-monitoring performance in industrial applications.