Product Overview

The Epro PR6424/010-120 16 mm Eddy Current Sensor is a non-contact displacement and vibration sensor designed for monitoring the condition of rotating machinery. Part of the EPRO PR6424 sensor family from Emerson, it is used in industrial machinery protection and condition-monitoring systems where accurate measurement of shaft movement is important for equipment reliability.

The sensor operates using the eddy current measurement principle. It detects changes in the distance between the probe tip and a conductive target without requiring direct mechanical contact. This makes it suitable for monitoring rotating shafts in equipment such as steam turbines, gas turbines, hydro turbines, compressors, pumps, and industrial fans.

The PR6424 series is designed for measuring radial and axial shaft displacement, dynamic vibration, shaft position, eccentricity, and speed-related signals. These measurements can help maintenance teams identify abnormal machine behavior before it develops into a more serious mechanical problem.

The PR6424/010-120 belongs to the 16 mm sensor category. Its nominal sensor head diameter is 16 mm, and the supplied product weight is approximately 0.2 kg. The exact probe length, cable construction, connector arrangement, and compatible signal converter should be confirmed from the complete model designation and product label before installation.

The sensor is normally used as part of a measurement chain rather than as an independent monitoring instrument. A compatible signal converter conditions the probe signal and provides an output that can be interpreted by a machinery protection or monitoring system.

Technical Specifications

Note: The measurement characteristics above are general PR6424 series specifications. Exact cable length, probe length, connector type, temperature limits, and configuration details should be checked against the complete PR6424/010-120 part number and its accompanying documentation.

Function and Working Principle

The PR6424/010-120 uses electromagnetic induction to measure the distance between its sensing tip and a conductive target. Unlike contact-based displacement instruments, it can monitor shaft movement without physically touching the rotating surface.

1. Eddy Current Measurement Principle

The sensor contains a coil that generates a high-frequency electromagnetic field around its probe tip. When a conductive metal target approaches the sensing area, eddy currents are induced in the target surface.

These currents affect the electrical characteristics of the sensor coil. The resulting change in impedance is related to the distance between the probe and the target.

When the sensor is paired with a compatible signal converter, this change can be converted into an electrical output proportional to the measured gap.

2. Shaft Displacement Measurement

Shaft displacement is an important parameter in rotating machinery. Excessive movement may indicate bearing wear, changes in operating conditions, mechanical looseness, or other equipment problems.

The PR6424 sensor measures the distance between its probe tip and the shaft surface. The resulting signal can be used to monitor changes in shaft position and displacement.

The PR6424 series has a nominal static measurement range of ±2.0 mm. Actual measurement accuracy depends on correct installation, target material, calibration, and the complete measurement chain.

3. Shaft Vibration Monitoring

Rotating machinery can develop vibration because of imbalance, misalignment, bearing deterioration, mechanical looseness, or changes in operating conditions.

The PR6424 sensor detects dynamic movement of the shaft relative to the probe. Its signal can be processed by a compatible monitoring system to evaluate vibration characteristics.

The general PR6424 dynamic measurement range is 0–1,000 μm peak-to-peak. This makes the sensor suitable for applications requiring non-contact shaft vibration measurement.

4. Position and Eccentricity Monitoring

The sensor can also be used to monitor shaft position and eccentricity. These measurements help identify changes in the rotating assembly’s mechanical condition.

For example, abnormal shaft position may be associated with bearing clearance changes, thermal expansion, or other mechanical influences. Monitoring these parameters provides useful information for equipment protection and maintenance.

5. Signal Conversion

The sensor probe is one part of a complete measurement system. Its electrical response must be processed by a compatible signal converter.

The converter conditions the probe signal and produces an output suitable for monitoring equipment. Correct matching of the probe, extension cable, converter, and monitoring channel is essential for reliable measurement.

Role in Industrial Machinery Monitoring Systems

The Epro PR6424/010-120 is designed to support machinery condition monitoring and protection. It can be integrated into systems that continuously measure shaft movement and provide information to operators and maintenance personnel.

Turbine Monitoring

Steam, gas, and hydro turbines contain rotating assemblies that operate under demanding mechanical and thermal conditions. Continuous monitoring of shaft vibration and displacement helps operators evaluate machine behavior during startup, normal operation, and shutdown.

The PR6424 series can be used as part of a turbine monitoring arrangement to measure radial or axial shaft movement.

Compressor Protection

Industrial compressors are used in petrochemical plants, gas processing facilities, refineries, and other process industries. Abnormal vibration or shaft displacement can affect equipment reliability and production continuity.

A properly installed eddy current sensor provides non-contact measurement data that can be evaluated by the machinery protection system.

Pump Monitoring

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

Shaft vibration and displacement measurements can help maintenance teams identify changes in mechanical condition. The sensor can be installed at suitable measurement locations according to the pump’s design and monitoring requirements.

PLC and DCS Integration

The PR6424 sensor is not a conventional PLC digital input device. It requires a compatible signal-conditioning and monitoring arrangement.

After signal conversion, the measurement output may be connected to a suitable machinery monitoring system, PLC, or DCS input, depending on the system architecture.

Engineers should verify the signal type, measurement range, channel configuration, and electrical interface before connecting the sensor to an automation controller.

Industrial Applications

1. Steam Turbines

Steam turbines are commonly used in power generation and industrial energy systems. Shaft vibration, displacement, and position measurements are important for evaluating rotor behavior.

The PR6424 sensor can be used in suitable turbine monitoring installations to provide non-contact measurements of shaft movement.

2. Gas Turbines

Gas turbines operate at high rotational speeds and under demanding thermal conditions. Continuous monitoring of rotating components is important for maintaining reliable operation.

A compatible PR6424 measurement chain can provide shaft displacement and vibration information for machinery monitoring systems.

3. Hydro Turbines

Hydro turbines are used in hydroelectric power stations and industrial energy facilities. Shaft movement monitoring helps operators assess the condition of rotating assemblies and associated bearings.

The sensor can support radial and axial displacement monitoring where the installation geometry and target surface meet the required specifications.

4. Industrial Compressors

Compressors are widely used in chemical plants, refineries, gas transportation, and manufacturing facilities. Abnormal rotor vibration can affect performance and equipment availability.

The PR6424 sensor provides a non-contact measurement method for monitoring shaft movement in compatible compressor installations.

5. Large Industrial Pumps

Large pumps are important in water treatment, power generation, and process industries. Monitoring shaft displacement and vibration can help identify developing mechanical problems.

The sensor may be used with a suitable monitoring system to provide continuous measurement information.

6. Industrial Fans

Large industrial fans and blowers operate in ventilation, combustion-air, cooling, and material-processing systems. Shaft vibration monitoring can help detect imbalance, misalignment, and other mechanical changes.

The PR6424 series provides a non-contact sensing option for suitable rotating equipment.

Installation and System Integration

Correct installation is essential for obtaining reliable measurement results. The probe position, target material, mounting arrangement, and signal-converter configuration all influence system performance.

1. Verify the Exact Sensor Configuration

Before installation, confirm the complete model designation, PR6424/010-120. Check the sensor label, probe dimensions, cable arrangement, connector type, and any supplied accessories.

Do not assume that every PR6424 probe has the same cable length, mechanical dimensions, or connector configuration.

2. Select the Correct Measurement Location

The probe should be installed at a location suitable for measuring the intended shaft movement.

For radial vibration measurement, the probe is normally positioned to observe the shaft surface in the required radial direction. Axial displacement measurement requires a suitable target surface and mounting arrangement.

The measurement location should provide adequate clearance and avoid interference from nearby mechanical components.

3. Check the Target Material

The PR6424 series is calibrated for a specified ferromagnetic steel target, with 42CrMo4 used as the standard reference material.

Different target materials can influence the sensor’s response. If the actual shaft material differs from the standard calibration material, verify the measurement-chain compatibility and any required calibration adjustments.

4. Set the Probe Gap

The probe-to-target distance is a critical installation parameter. The general PR6424 series specification gives a nominal center air gap of approximately 2.7 mm.

The actual gap should be established using the manufacturer’s installation procedure and the corresponding signal converter. Incorrect gap adjustment may reduce the available measurement range or cause the output to operate outside its intended linear region.

5. Connect the Signal Converter

The PR6424 probe must be paired with a compatible converter and extension cable where required by the measurement system.

Check the complete measurement-chain configuration before connecting the sensor. Probe, cable, and converter combinations must be compatible in terms of electrical characteristics and calibration.

6. Route and Protect the Cable

Route the sensor cable away from high-power conductors and sources of electrical interference where possible.

Avoid excessive bending, pulling, crushing, or abrasion. Cable protection and suitable fastening are important in environments subject to vibration, heat, or mechanical movement.

7. Commission and Verify the Measurement

After installation, check the mechanical mounting, probe gap, cable connections, converter compatibility, and monitoring-channel configuration.

Verify that the measurement output changes correctly when the target position changes. Confirm that the monitoring system displays reasonable static and dynamic values before placing the equipment into normal service.

Compatible System Components

The PR6424/010-120 is normally used as part of a complete eddy current measurement chain.

The sensor should not be connected directly to an arbitrary controller input. The required signal converter and monitoring interface must be identified before system integration.

Alternative Models and Replacement Considerations

The PR6424 belongs to a broader EPRO eddy current sensor family. Other models may have different sensing diameters, measuring ranges, mechanical dimensions, or temperature capabilities.

When replacing the PR6424/010-120, check:

• Complete sensor model and suffix.
• Sensor head diameter.
• Probe length and mounting dimensions.
• Cable length and cable construction.
• Connector type and pin arrangement.
• Signal converter compatibility.
• Target material and calibration requirements.
• Static and dynamic measurement ranges.
• Operating temperature and environmental conditions.
• Monitoring-system channel configuration.

A sensor with the same 16 mm head diameter is not necessarily a direct replacement. The full measurement chain must be checked to ensure that the replacement provides the required measurement characteristics.

Key Advantages

Non-Contact Measurement

The eddy current principle allows the sensor to measure shaft movement without physical contact. This is important for rotating machinery where continuous mechanical contact would be impractical.

Shaft Displacement Monitoring

The PR6424 series supports static displacement measurement, providing information about shaft position and changes in mechanical alignment or operating condition.

Dynamic Vibration Measurement

The sensor can detect dynamic shaft movement and provide measurement information for machinery vibration monitoring.

Industrial Rotating Machinery Applications

The PR6424 series is designed for critical rotating equipment, including turbines, compressors, pumps, and fans.

Compact 16 mm Sensor Head

The 16 mm sensing head supports installation in suitable machinery-monitoring locations where a larger probe may not be practical.

Integration with Monitoring Systems

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

Established EPRO Measurement Technology

The PR6424 family is used in industrial machinery monitoring applications where reliable shaft displacement and vibration measurements are required.

Technical FAQs

1. What is the Epro PR6424/010-120?

The Epro PR6424/010-120 is a 16 mm eddy current sensor designed for non-contact measurement of shaft displacement, vibration, position, eccentricity, and speed-related parameters 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 the eddy current principle. An electromagnetic field generated by the probe interacts with a conductive target, and changes in the electrical characteristics of the probe are used to determine the distance to the target.

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

The general PR6424 series specification gives a sensitivity of 4 V/mm, with linearity of up to ±1.5% under the specified measurement conditions.

5. What is the static measurement range?

The general PR6424 series static measurement range is ±2.0 mm.

6. What is the dynamic measurement range?

The general dynamic measurement range is 0–1,000 μm peak-to-peak.

7. Which machines can use this sensor?

Suitable applications include steam turbines, gas turbines, hydro turbines, compressors, pumps, and industrial fans. The actual installation must meet the sensor’s mechanical and electrical requirements.

8. Can the sensor connect directly to a PLC?

It should not be treated as a standard PLC input device. A compatible signal converter or monitoring interface is normally required to process the probe signal before it is connected to an automation system.

9. What is the supplied weight?

The supplied product weight is 0.2 kg. The official general PR6424 specification also gives an approximate weight of 200 g for the sensor with a 1 m cable and without armor.

10. What should be checked before replacing an existing PR6424 sensor?

Verify the complete model number, probe dimensions, cable and connector configuration, converter compatibility, target material, calibration, and measurement range. Matching the sensor diameter alone is not sufficient.

Procurement and Maintenance Recommendations

When purchasing the Epro PR6424/010-120, confirm the complete model number and the physical configuration of the supplied sensor. The probe length, cable construction, connector arrangement, and included accessories should be checked carefully, particularly when replacing an existing sensor in a machinery protection system.

For maintenance projects, inspect the probe body, sensing tip, mounting thread, cable insulation, and connector condition. Mechanical damage, loose connections, or damaged cable insulation can affect the reliability of the measurement signal.

The installation gap should be checked according to the manufacturer’s procedure. A probe that is positioned too close to or too far from the target may operate outside the intended measurement range.

The sensor should also be evaluated as part of the complete measurement chain. Confirm that the extension cable, signal converter, and monitoring channel are compatible and correctly calibrated.

For critical rotating equipment, retain records of sensor model numbers, mounting positions, calibration information, and measurement-channel settings. This documentation can simplify troubleshooting and future replacement work.

Conclusion

The Epro PR6424/010-120 16 mm Eddy Current Sensor is designed for non-contact shaft displacement and vibration measurement in critical industrial rotating machinery. Its 16 mm sensing head and eddy current measurement technology make it suitable for use in turbine, compressor, pump, and fan monitoring applications.

The PR6424 series provides a general static measurement range of ±2.0 mm, a dynamic range of 0–1,000 μm peak-to-peak, and sensitivity of 4 V/mm. When installed with a compatible extension cable, signal converter, and machinery monitoring system, the sensor can provide important information about shaft movement and machine operating condition.

For procurement and replacement, checking the complete model designation and measurement-chain compatibility is essential to maintaining reliable machinery monitoring.