Product Overview

The EPRO PR6424/013-030 16 mm Eddy Current Sensor is a non-contact displacement measurement probe designed for monitoring the operating condition of critical rotating machinery. Manufactured under the EPRO product line associated with Emerson, the PR6424 series is used in machinery protection and condition-monitoring systems where accurate shaft movement measurements are important for equipment reliability.

The sensor operates using the eddy current measurement principle. It generates an electromagnetic field at the sensing tip, and when a conductive target such as a ferromagnetic steel shaft approaches the probe, the interaction changes the electrical characteristics of the sensing coil. A compatible signal converter processes this change into a measurement signal representing the distance between the probe and the target.

The PR6424 series is designed for monitoring radial and axial shaft displacement, vibration, shaft position, eccentricity, and speed-related parameters. Typical applications include steam turbines, gas turbines, hydro turbines, compressors, pumps, and industrial fans.

The PR6424/013-030 belongs to the 16 mm sensor family. Its compact sensing head is suitable for installations where a larger probe may not fit around the monitored shaft or within the available machine mounting space. When installed with a compatible signal converter and extension cable, it can form part of a complete shaft-monitoring measurement chain.

For industrial maintenance teams, the correct probe configuration is important. Cable construction, connector type, probe length, mounting thread, and converter compatibility should be checked against the full ordering code before installation or replacement.

Technical Specifications

Note: The measurement figures above are PR6424 series reference specifications. Confirm the exact cable length, connector arrangement, probe dimensions, and temperature limits for the PR6424/013-030 ordering code before procurement.

Function and Working Principle

The PR6424/013-030 uses eddy current technology to measure the distance between the probe tip and a conductive target. Unlike contact-based measuring devices, the probe does not need to touch the rotating shaft. This makes it suitable for continuous monitoring of machinery operating at high speeds.

1. Non-Contact Eddy Current Measurement

The probe contains a sensing coil that generates an alternating electromagnetic field. When a conductive metal target enters this field, eddy currents are induced on the target surface.

The eddy currents affect the impedance of the probe coil. A compatible signal converter detects this change and converts it into an electrical measurement signal.

As the distance between the probe and shaft changes, the output changes accordingly. This enables the monitoring system to determine shaft movement without mechanical contact.

2. Shaft Displacement Measurement

The sensor can measure changes in the position of a rotating shaft relative to a fixed reference point. This is important in machinery where excessive movement may indicate bearing wear, alignment problems, mechanical looseness, or other abnormal conditions.

The PR6424 series provides a static measurement range of approximately ±2.0 mm. This allows it to monitor changes in shaft position within the specified measurement range.

3. Shaft Vibration Monitoring

During normal operation, rotating machinery may experience small periodic shaft movements. These movements can be measured as dynamic displacement.

The PR6424 series supports dynamic measurement ranges up to 1,000 μm. When paired with compatible monitoring equipment, the measurement signal can be used to evaluate vibration trends and identify changes in machine operating conditions.

4. Eccentricity and Position Monitoring

Shaft eccentricity describes the deviation of a rotating shaft from its expected geometric center. Excessive eccentricity may result from shaft deformation, uneven thermal expansion, mechanical wear, or installation problems.

The sensor provides non-contact measurements that can help monitoring systems identify changes in shaft position and eccentricity.

5. Signal Conversion

The sensor probe is a measurement element within a complete monitoring system. It must be paired with the appropriate signal converter and cable configuration.

The converter processes the probe’s electrical characteristics and generates a usable output for machinery monitoring equipment. Correct matching of the probe, extension cable, and converter is essential for maintaining measurement accuracy.

Role in Industrial Machinery Protection Systems

The PR6424/013-030 is intended for applications where continuous shaft-condition monitoring is important. It can be incorporated into a machinery protection system that collects measurements from multiple locations and evaluates equipment operating conditions.

Turbine Monitoring

Steam, gas, and hydro turbines contain rotating shafts that operate under demanding mechanical and thermal conditions. Shaft displacement and vibration measurements can help operators identify abnormal movement and changes in operating behavior.

The sensor can be installed at appropriate measurement points around the turbine shaft, subject to the machine manufacturer’s monitoring design.

Compressor Protection

Industrial compressors are often critical assets in chemical plants, refineries, gas processing facilities, and manufacturing operations.

Shaft vibration and displacement measurements can help identify changes associated with bearing wear, rotor imbalance, mechanical looseness, and other developing problems.

Pump Condition Monitoring

Large industrial pumps may operate continuously and are often connected to important production processes. Monitoring shaft movement can provide useful information about mechanical condition.

The PR6424 series can be used in suitable pump monitoring arrangements to measure shaft displacement and vibration.

PLC and Monitoring-System Integration

The sensor itself does not function as a standalone PLC input device. Its signal must first be processed by a compatible converter or monitoring interface.

The resulting measurement signal can then be connected to suitable machinery protection equipment, monitoring systems, or control-system interfaces. Engineers should confirm the output format and electrical requirements before designing the interface.

Industrial Applications

The EPRO PR6424/013-030 is designed for machinery condition monitoring, particularly where non-contact measurement of rotating shafts is required.

1. Steam Turbines

Steam turbines operate at high rotational speeds and require reliable monitoring of shaft movement. Excessive vibration or changes in shaft position may indicate mechanical deterioration or abnormal operating conditions.

The PR6424 series can provide displacement measurements for suitable turbine monitoring installations.

2. Gas Turbines

Gas turbines operate under high-temperature and high-speed conditions. Monitoring shaft displacement and vibration is important for evaluating rotor behavior and supporting machinery protection strategies.

Probe temperature limits and installation arrangements must be checked carefully against the exact sensor configuration and the machine’s operating environment.

3. Hydro Turbines

Hydroelectric generating equipment requires continuous monitoring to support stable operation. Shaft position and vibration measurements can help maintenance personnel evaluate rotating assembly behavior.

The PR6424 series may be used in appropriate hydro-turbine monitoring systems.

4. Industrial Compressors

Centrifugal and other large rotating compressors require monitoring of shaft movement and vibration. Changes in measured values may help identify mechanical problems before they develop into serious equipment failures.

The sensor can be installed at suitable shaft-monitoring locations when the probe dimensions and converter arrangement meet the equipment requirements.

5. Pumps and Fans

Large pumps and industrial fans may operate continuously in power plants, chemical facilities, water treatment plants, and manufacturing environments.

Non-contact displacement measurement can provide information about shaft movement and help maintenance teams evaluate changes in machine condition.

6. Generators and Rotating Machinery

Generators and other large rotating machines may require shaft-position and vibration monitoring. A suitable eddy current probe can contribute to a broader condition-monitoring arrangement that tracks mechanical performance over time.

Installation and System Integration

Correct installation is essential for measurement accuracy and long-term reliability. The probe must be positioned appropriately, connected to compatible equipment, and installed according to the manufacturer’s technical instructions.

1. Verify Probe Compatibility

Before installation, confirm the full model number PR6424/013-030 and check its compatibility with the intended signal converter and extension cable.

Do not assume that every PR6424 probe configuration uses the same cable length, connector, or converter arrangement. Verify these details using the applicable ordering information.

2. Select the Correct Mounting Position

The probe should be installed at the measurement location specified by the machinery monitoring design. The sensing tip must face the intended conductive target surface.

The mounting arrangement should provide adequate mechanical stability and prevent unwanted movement during machine operation.

3. Set the Initial Air Gap

The PR6424 series has a nominal center air gap of approximately 2.7 mm. The actual installation gap must be established according to the sensor and converter instructions.

Incorrect probe positioning may cause the measurement signal to operate outside its linear range, resulting in inaccurate readings or insufficient measurement margin.

4. Verify Target Material

The PR6424 series is designed for use with ferromagnetic steel targets, with 42CrMo4 identified as a standard reference material in the technical specifications.

Target material affects the sensor’s measurement characteristics. Engineers should confirm that the shaft material and surface condition meet the requirements of the applicable calibration.

5. Protect the Cable and Connector

The sensor cable should be routed away from excessive mechanical stress, sharp edges, and sources of electrical interference.

Respect the minimum bending radius specified for the exact cable construction. Avoid pulling directly on the cable or connector during installation.

Inspect connector contacts and cable insulation before connecting the sensor to the converter.

6. Connect the Signal Converter

Use a compatible EPRO signal converter and the appropriate extension cable. Confirm connector type, cable length, electrical compatibility, and calibration requirements.

A mismatch between the probe and converter can affect measurement accuracy or prevent the monitoring system from operating correctly.

7. Verify the Measurement Signal

After installation, check the initial gap, output response, signal stability, and measurement range. Compare the measured values with the commissioning baseline.

If the signal is unstable, inspect the cable, connectors, grounding, probe mounting, target surface, and converter configuration before returning the equipment to normal operation.

Compatible System Components

A complete PR6424 measurement installation may include several components working together.

These components are examples of a complete measurement arrangement. They are not necessarily included with the sensor itself.

Alternative Models and Replacement Considerations

The PR6424 series includes multiple ordering configurations. Although they may share the same 16 mm sensor family, differences in cable construction, length, connector, and mechanical arrangement can affect replacement compatibility.

Before selecting an alternative, compare:

• Sensor head diameter.
• Full ordering code and probe configuration.
• Sensitivity and linearity.
• Static and dynamic measuring ranges.
• Nominal air gap.
• Cable length and construction.
• Connector type.
• Target material and shaft diameter.
• Operating temperature limits.
• Signal converter compatibility.
• Mounting thread and mechanical dimensions.

A replacement should not be selected based only on the 16 mm sensor diameter. Differences in the measurement chain can affect calibration and system performance.

Key Advantages

Non-Contact Measurement

The eddy current principle allows shaft displacement to be measured without physical contact, reducing mechanical wear at the sensing point.

High Measurement Sensitivity

The PR6424 series has a reference sensitivity of 4 V/mm, supporting precise monitoring of small changes in shaft position.

Static and Dynamic Measurement

The series supports both static position measurement and dynamic displacement monitoring, making it suitable for multiple machinery protection applications.

Compact 16 mm Sensor Head

The 16 mm sensing head can be installed in suitable locations where mounting space is limited.

Industrial Machinery Applications

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

Stable Measurement Characteristics

The published series specifications include long-term drift below 0.3%, supporting applications where consistent monitoring performance is required.

Integration with Monitoring Systems

When paired with a compatible converter, the sensor can provide measurement information for machinery protection and condition-monitoring equipment.

Technical FAQs

1. What is the EPRO PR6424/013-030?

The PR6424/013-030 is a 16 mm eddy current sensor designed for non-contact measurement of shaft displacement and vibration in rotating machinery.

2. What is the main function of this sensor?

It measures changes in the distance between the sensor tip and a conductive target. These measurements can be used to monitor shaft position, radial or axial displacement, vibration, and eccentricity.

3. What is the sensor head diameter?

The sensor head diameter is 16 mm.

4. What is the sensitivity of the PR6424 series?

The published series sensitivity is 4 V/mm, with linearity of approximately ±1.5% or better under the specified measurement conditions.

5. What is the measuring range?

The series reference static measuring range is ±2.0 mm, while the dynamic measuring range is 0–1,000 μm.

6. What target material should be used?

The PR6424 series is specified for ferromagnetic steel targets. The target material and surface characteristics should be considered when setting up the measurement system.

7. Does the sensor require a signal converter?

Yes. The probe is normally used with a compatible signal converter and extension cable. The converter processes the sensor response and provides a usable measurement output.

8. Can the PR6424/013-030 measure shaft vibration?

Yes. The PR6424 series supports dynamic displacement measurement and can be used in suitable shaft vibration monitoring systems.

9. Which machines can use this sensor?

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

10. What should be checked before replacing an existing probe?

Confirm the complete model number, sensor diameter, cable length, connector, mounting arrangement, converter compatibility, and calibration requirements. A matching sensor diameter alone does not guarantee compatibility.

Procurement and Maintenance Recommendations

When purchasing the EPRO PR6424/013-030, verify the complete ordering code and ensure that the supplied probe matches the existing monitoring system. Pay particular attention to the cable configuration, connector type, probe dimensions, and compatible signal converter.

For replacement projects, request clear product photographs and confirm the sensor’s condition, cable integrity, connector condition, and identification markings. If the sensor is supplied with additional cables or accessories, confirm which items are included in the package.

During routine maintenance, inspect the sensor mounting, cable routing, connector contacts, and probe surface. Check the initial air gap and compare measurement values with the established commissioning baseline.

If readings become unstable, inspect the complete measurement chain rather than replacing the probe immediately. Cable damage, loose connectors, incorrect converter matching, unsuitable target material, and improper probe positioning can all affect measurement performance.

For critical turbine and compressor applications, maintain accurate records of sensor locations, calibration information, probe replacement dates, and monitoring-system configuration. This information can simplify future maintenance and reduce the risk of installing an incompatible replacement.

Conclusion

The EPRO PR6424/013-030 16 mm Eddy Current Sensor is designed for non-contact shaft displacement and vibration measurement in critical rotating machinery. Based on the PR6424 series specifications, it provides 4 V/mm sensitivity, a ±2.0 mm static measurement range, and a dynamic measurement range of up to 1,000 μm.

Its applications include turbines, compressors, pumps, fans, and other rotating equipment requiring continuous shaft-condition monitoring. For reliable operation, the probe must be correctly installed and paired with a compatible extension cable and signal converter.

When sourcing or replacing this sensor, verify the complete ordering code and all mechanical and electrical interface details to ensure compatibility with the existing machinery protection system.