Product Overview

The EPRO PR6424/012-101 16 mm Eddy Current Sensor is a non-contact displacement measurement probe designed for monitoring the condition and operating behavior of critical rotating machinery. It belongs to the PR6424 sensor family developed for industrial machinery protection and condition monitoring applications.

Manufactured under the EPRO product line of Emerson, the PR6424 series is commonly used in steam turbines, gas turbines, hydro turbines, compressors, pumps, and industrial fans. These machines operate with rotating shafts that require continuous monitoring to identify abnormal vibration, displacement, shaft position changes, and other mechanical conditions.

The PR6424/012-101 uses eddy current measurement technology. Instead of making physical contact with the rotating shaft, the sensor detects changes in the electromagnetic field between its sensing tip and a conductive target. These changes are converted into an electrical measurement signal by a compatible signal conditioning system.

The sensor has a nominal head diameter of 16 mm, making it suitable for applications requiring shaft displacement and vibration measurements on larger rotating machines. The PR6424 family is designed for measuring radial and axial shaft movement, static position, eccentricity, and speed-related signals.

A complete measurement installation normally includes a compatible sensor probe, extension cable where required, and signal converter. The correct combination is important because sensor and converter configurations must be electrically compatible.

The PR6424/012-101 is intended for industrial machinery monitoring systems where reliable displacement information is necessary for equipment protection, operational assessment, and maintenance planning.

Technical Specifications

Note: The technical performance figures above describe the PR6424 sensor family. Cable length, connector arrangement, armor, thread, and temperature limits should be verified against the specific PR6424/012-101 configuration and its original datasheet.

Function and Working Principle

The PR6424/012-101 uses eddy current technology to measure the distance between the probe tip and a conductive target. In rotating machinery applications, the target is typically a metallic shaft surface.

The sensor produces an electromagnetic field at its sensing tip. When a conductive target approaches the probe, eddy currents are induced in the target surface. These currents affect the probe’s electromagnetic characteristics, producing a measurable change in the sensor circuit.

A compatible signal converter processes this change and generates an electrical output proportional to the distance between the probe and the target.

1. Non-Contact Displacement Measurement

The sensor measures shaft movement without touching the rotating component. This is particularly important in high-speed machinery, where direct mechanical contact would cause wear and could interfere with normal operation.

The non-contact measurement method allows continuous monitoring while the machine is running. It can be used to identify changes in shaft position and movement that may indicate mechanical abnormalities.

2. Shaft Vibration Monitoring

Rotating shafts can experience vibration due to imbalance, misalignment, bearing problems, mechanical looseness, or changing operating conditions.

The PR6424 sensor detects dynamic changes in the gap between the probe and shaft. When installed in an appropriate monitoring arrangement, these measurements can be used to evaluate shaft vibration.

The PR6424 family provides a dynamic measurement range of approximately 0–1,000 μm, depending on the complete measurement system and configured operating conditions.

3. Shaft Position Measurement

In addition to dynamic vibration, the sensor can measure static shaft position within its specified measurement range.

This information is useful for monitoring shaft movement and identifying changes in the mechanical position of rotating equipment. Axial displacement monitoring is particularly important in turbines and other machinery where excessive shaft movement may indicate a serious mechanical condition.

4. Eccentricity Measurement

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

By measuring the distance between the probe and shaft surface, the sensor can provide information used to assess eccentricity. This is useful during startup, shutdown, and other operating conditions where shaft movement may differ from steady-state behavior.

5. Signal Conversion and Processing

The sensor probe is one part of a complete measurement chain. Its output must be connected to a compatible signal converter or monitoring system.

The converter processes the probe signal and provides an output suitable for machinery monitoring equipment. The resulting information can be used for vibration analysis, alarm generation, protection functions, and maintenance diagnostics.

Role in Industrial Machinery Protection Systems

The EPRO PR6424/012-101 is designed to provide measurement information for machinery condition monitoring and protection systems.

In critical rotating equipment, changes in shaft vibration and displacement can provide early indications of mechanical problems. Continuous monitoring allows operators and maintenance personnel to evaluate equipment behavior before abnormal conditions develop into more serious failures.

Turbine Monitoring

Steam and gas turbines operate under demanding mechanical and thermal conditions. Shaft vibration and axial movement must be monitored to help protect rotating components.

The PR6424 sensor can be installed near suitable shaft measurement locations to provide displacement information for the machinery monitoring system.

Compressor Monitoring

Industrial compressors are widely used in oil and gas processing, chemical plants, refineries, and manufacturing facilities.

Shaft vibration measurements can help identify developing mechanical conditions such as imbalance, misalignment, and bearing-related problems. The PR6424 sensor can form part of a monitoring arrangement designed for these applications.

Pump Monitoring

Large industrial pumps may operate continuously and are often essential to production processes. Shaft displacement and vibration measurements can support maintenance assessment and help identify abnormal mechanical behavior.

Fan and Blower Monitoring

Industrial fans and blowers can experience vibration caused by rotor imbalance, bearing wear, or mechanical installation problems. Non-contact shaft measurement provides useful information for evaluating rotating equipment condition.

Industrial Applications

1. Steam Turbines

Steam turbines are used in power generation and industrial energy systems. Their rotating shafts operate at high speeds, making vibration and displacement monitoring important for machinery protection.

The PR6424 sensor can be used in suitable monitoring arrangements to measure shaft movement and provide data for evaluating turbine operating conditions.

2. Gas Turbines

Gas turbines operate under high temperatures and demanding mechanical conditions. Continuous shaft monitoring helps operators assess vibration and displacement behavior.

The sensor’s non-contact measurement principle makes it suitable for applications where the probe must measure a rotating shaft without physical contact.

3. Hydro Turbines

Hydroelectric generating equipment uses large rotating assemblies that require long-term condition monitoring. Shaft movement measurements can help maintenance teams evaluate mechanical stability and identify changes in equipment behavior.

4. Centrifugal Compressors

Centrifugal compressors are used in refineries, petrochemical facilities, gas transportation systems, and industrial processing plants.

Shaft vibration and displacement measurements can support the monitoring of rotor dynamics and help identify abnormal operating conditions.

5. Industrial Pumps

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

The PR6424 sensor can be incorporated into suitable pump monitoring systems where non-contact shaft measurement is required.

6. Industrial Fans

Large fans and blowers are used in ventilation, cooling, combustion-air supply, and process exhaust systems.

Monitoring shaft vibration can help identify mechanical deterioration and support preventive maintenance programs.

Installation and System Integration

Correct installation is essential for obtaining reliable measurements from the PR6424/012-101. Probe positioning, target material, cable routing, and converter compatibility all influence measurement performance.

1. Select the Correct Measurement Location

The sensor should be installed at a suitable measurement location where the shaft surface provides a consistent target.

The mounting position must allow the probe to measure the intended radial or axial movement. The shaft surface should be suitable for eddy current measurement and free from conditions that would interfere with the electromagnetic field.

The selected location should also provide sufficient mechanical clearance for the probe and its cable.

2. Set the Correct Probe Gap

The gap between the probe tip and the target shaft is an important installation parameter.

The PR6424 family has a nominal center air gap of approximately 2.7 mm. The actual setup should follow the manufacturer’s installation and calibration instructions.

An incorrect gap can cause the measurement to operate outside its intended linear range, resulting in inaccurate readings or reduced measurement performance.

3. Verify Target Material

Eddy current sensors require a suitable conductive target. The PR6424 family specifications reference ferromagnetic steel, with 42CrMo4 as a standard target material.

Different shaft materials can affect sensor calibration and measurement characteristics. The target material should therefore be checked when selecting or replacing the sensor.

4. Check Cable and Connector Configuration

The complete sensor configuration must match the extension cable and signal converter used in the monitoring system.

Different PR6424 suffixes may represent variations in cable length, cable armor, connector arrangement, and other configuration details.

Before installation, verify the full model number, cable termination, and converter compatibility. Do not assume that every PR6424 probe can be connected to the same cable assembly without checking the electrical specifications.

5. Connect the Signal Converter

The sensor should be connected to a compatible EPRO signal converter. The converter processes the sensor signal and provides the required measurement output to the machinery monitoring system.

The complete measurement chain should be checked for electrical compatibility, cable condition, grounding, and correct calibration.

6. Perform Calibration and Functional Testing

After installation, verify the sensor gap and measurement response according to the manufacturer’s procedures.

Functional testing should confirm that the signal changes consistently with target movement and that the converter provides the expected output.

Record the installed probe model, cable arrangement, converter model, calibration information, and measurement location for future maintenance.

Compatible System Components

The PR6424/012-101 is generally used as part of a complete eddy current measurement system.

The components listed are examples of the wider PR6424 measurement system. They are not necessarily included with the PR6424/012-101 sensor. Always confirm the manufacturer’s compatibility documentation before combining components.

Alternative Models and Replacement Considerations

When replacing a PR6424/012-101, the replacement should be selected according to the measurement requirements and complete system configuration.

Before selecting a replacement, check the following:

• Complete sensor model and suffix.
• Sensor head diameter.
• Probe length and mounting thread.
• Cable length and cable armor.
• Connector type and termination.
• Signal converter model.
• Measurement sensitivity and range.
• Target shaft material and diameter.
• Operating temperature.
• Required monitoring system input.

A replacement sensor with the same 16 mm head diameter may still have a different cable or electrical configuration. Exact model verification is therefore essential.

Key Advantages

Non-Contact Measurement

The sensor measures shaft displacement without physical contact, avoiding mechanical wear between the probe and rotating shaft.

High Measurement Sensitivity

The PR6424 family provides a sensitivity of 4 V/mm, supporting detailed measurement of shaft movement when used with a compatible converter.

Static and Dynamic Measurement

The sensor can support both static position measurement and dynamic shaft displacement monitoring within its specified operating range.

Industrial Machinery Applications

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

Stable Measurement Performance

The family specifications include low long-term drift, supporting continuous monitoring when the sensor is correctly installed and calibrated.

Integration with EPRO Monitoring Equipment

The sensor can be incorporated into compatible EPRO measurement and machinery protection systems through the appropriate cable and signal converter arrangement.

Support for Condition-Based Maintenance

Continuous shaft displacement measurements can help maintenance teams identify changes in rotating equipment behavior and plan inspections based on actual operating conditions.

Technical FAQs

1. What is the EPRO PR6424/012-101?

The EPRO PR6424/012-101 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 conductive target’s distance affect the probe signal.

4. What is the measurement range of the PR6424 family?

The family specifications include a static measurement range of approximately ±2.0 mm and a dynamic measurement range of 0–1,000 μm.

5. What is the sensitivity?

The typical PR6424 family sensitivity is 4 V/mm, with a specified linearity of up to ±1.5%.

6. What type of equipment uses this sensor?

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

7. Does the sensor operate without physical contact?

Yes. The PR6424 uses non-contact eddy current measurement, allowing it to monitor shaft movement without touching the rotating surface.

8. Does the sensor work independently?

The probe is normally used with a compatible extension cable and signal converter. The complete measurement system must be configured according to the manufacturer’s requirements.

9. Can the PR6424/012-101 replace another PR6424 model?

Not automatically. Different suffixes may indicate different cable lengths, armor, connector arrangements, or other configuration details. Verify the complete model and converter compatibility before replacement.

10. What is the weight of the PR6424/012-101?

The supplied product listing weight is 0.2 kg. The actual shipping weight may differ depending on packaging and included accessories.

Procurement and Maintenance Recommendations

When purchasing the EPRO PR6424/012-101, verify the complete model number and confirm that the supplied probe matches the original installation requirements.

For replacement projects, check the sensor head diameter, cable configuration, connector type, probe mounting dimensions, signal converter, and measurement range. These details are important because a probe with a similar appearance may not be electrically interchangeable.

For used or refurbished sensors, inspect the probe body, sensing tip, cable insulation, connector, and threaded mounting section. Request clear photographs of the nameplate or product identification and confirm the condition of the cable.

During routine maintenance, inspect cable routing and mounting stability. Check for damaged insulation, loose connections, contamination, and changes in the probe-to-shaft gap. Calibration and functional testing should follow the manufacturer’s procedures.

For critical machinery, retain the original sensor configuration records, including the converter model, cable length, mounting location, calibration information, and monitoring channel settings. These records help reduce replacement errors and simplify future troubleshooting.

Conclusion

The EPRO PR6424/012-101 16 mm Eddy Current Sensor is designed for non-contact shaft displacement and vibration monitoring in critical rotating machinery. Its 16 mm sensing head and the PR6424 family’s measurement capabilities make it suitable for applications involving turbines, compressors, pumps, and industrial fans.

With typical family specifications including 4 V/mm sensitivity, a ±2.0 mm static measurement range, and a dynamic measurement range of 0–1,000 μm, the PR6424 series supports machinery condition monitoring and protection applications.

For purchasing and replacement, the complete model suffix must be checked carefully. Correct cable configuration, signal converter compatibility, target material, and installation gap are all essential for reliable measurement performance.