Product Overview

The EPRO PR6424/013-100 16 mm Eddy Current Sensor is a non-contact displacement measurement probe designed for monitoring the operating condition of rotating machinery. It belongs to the PR6424 series developed for machinery protection and condition monitoring applications, including steam turbines, gas turbines, hydro turbines, compressors, pumps, and industrial fans.

The sensor uses eddy current technology to measure the distance between its sensing tip and a conductive target, typically a ferromagnetic steel shaft. Because measurement takes place without physical contact, the probe can monitor shaft movement without introducing mechanical wear between the sensor and the rotating component.

The PR6424 series is designed to measure several important machinery parameters, including radial shaft vibration, axial displacement, shaft position, eccentricity, and speed-related signals. These measurements are useful for identifying abnormal rotor movement, changes in shaft position, and developing mechanical problems before they lead to equipment failure.

The PR6424/013-100 has a nominal sensing-head diameter of 16 mm. It is intended for use as part of a compatible measurement system, which generally includes the sensor probe, appropriate extension cable or connection arrangement, and a signal converter.

When installed and calibrated correctly, the sensor provides a displacement-related electrical signal that can be processed by a monitoring instrument or machinery protection system. This allows operators and maintenance engineers to observe shaft behavior continuously and evaluate machine condition during operation.

Technical Specifications

Note: The technical performance figures above are published PR6424 series specifications. The exact cable construction, connector, thread arrangement, and temperature limits for the PR6424/013-100 should be confirmed against its individual nameplate and datasheet revision.

Function and Working Principle

The PR6424/013-100 operates using the eddy current measurement principle. This technology is widely used in machinery monitoring because it allows displacement measurements to be made without direct contact with the rotating shaft.

1. Eddy Current Measurement

The sensor contains an electromagnetic coil inside its sensing head. When the probe is supplied by a compatible signal converter, the coil generates a high-frequency electromagnetic field around the sensing tip.

When a conductive metallic target approaches the sensor, eddy currents are induced in the target surface. These currents change the electrical characteristics of the probe coil.

The resulting change in impedance is related to the distance between the probe and the target. The measurement system converts this change into an electrical signal that represents the displacement of the shaft or other monitored component.

2. Shaft Vibration Measurement

As a rotating shaft moves due to mechanical vibration, its distance from the stationary probe changes. The sensor detects these variations and produces a corresponding output signal.

The resulting measurement can be used to evaluate shaft vibration and identify abnormal movement. Maintenance engineers can compare vibration trends with operating conditions to determine whether further inspection is necessary.

3. Shaft Position and Axial Displacement

The sensor can also be used for static position measurements within its specified operating range.

In turbine applications, axial displacement monitoring is particularly important because excessive rotor movement may indicate changes in thrust-bearing condition or other mechanical problems.

The probe can measure the relative position of a suitable metallic target, provided that its mounting location, target surface, and measurement range are correctly selected.

4. Eccentricity Measurement

Shaft eccentricity describes the deviation of a rotating shaft from its ideal geometric center. Changes in eccentricity may be associated with shaft deformation, uneven thermal expansion, installation conditions, or mechanical damage.

By monitoring shaft-to-probe distance, the PR6424 measurement system can provide data for evaluating eccentricity and other rotor-related conditions.

5. Speed and Key-Related Monitoring

The PR6424 series can also be used in suitable speed and key-related measurement arrangements. As a rotating target passes the probe, the resulting signal can provide information about rotational movement.

The final measurement function depends on target geometry, probe installation, converter configuration, and the connected monitoring instrument.

Role in Industrial Machinery Protection Systems

The PR6424/013-100 is a sensing component rather than a complete standalone monitoring system. It normally works with compatible signal-conditioning and monitoring equipment.

1. Signal Converter Integration

The eddy current probe requires a compatible signal converter to supply the sensor and process its measurement response.

The converter translates the probe’s electrical characteristics into a usable output signal. The resulting signal can then be connected to a machinery monitoring system, protection instrument, or other compatible measurement equipment.

Correct matching of the probe, cable, and converter is essential. Different PR6424 configurations may require specific cable and converter arrangements.

2. Machinery Monitoring Systems

The sensor can provide measurement information to machinery monitoring equipment used in power generation, petrochemical processing, and other industrial facilities.

The monitoring system evaluates the incoming signals and presents information such as shaft displacement, vibration, or position. Depending on the system configuration, operators may use this information for alarms, condition assessment, and protective shutdown logic.

3. PLC and DCS Integration

A PLC or distributed control system can receive relevant monitoring information through compatible monitoring modules or signal interfaces.

For example, a machinery protection system may provide a processed signal to a plant control system. The PLC or DCS can then display the measurement, record operating trends, or coordinate alarms with other process conditions.

The sensor should not be assumed to connect directly to standard PLC analog inputs. Its required converter and signal-conditioning arrangement must be established first.

4. Turbine Protection

In turbine installations, shaft vibration and axial position are important operating parameters. Excessive vibration or abnormal shaft movement may indicate developing mechanical problems.

The PR6424 series supports non-contact measurement of these parameters, allowing compatible machinery protection systems to monitor rotor behavior during operation.

Industrial Applications

The EPRO PR6424/013-100 is intended for applications where reliable non-contact displacement measurement is required.

1. Steam Turbines

Steam turbines operate under demanding mechanical and thermal conditions. Continuous shaft monitoring helps operators evaluate rotor vibration, axial displacement, and changes in shaft position.

The PR6424 series can be installed at suitable measurement locations to provide displacement signals for compatible turbine monitoring systems.

2. Gas Turbines

Gas turbines contain high-speed rotating assemblies that require continuous condition monitoring. Shaft vibration and position measurements help maintenance teams assess rotor behavior and identify abnormal operating trends.

A correctly installed eddy current sensor can contribute to the monitoring of these critical mechanical parameters.

3. Hydro Turbines

Hydro turbine installations use rotating shafts, bearings, and associated mechanical assemblies that may require vibration and displacement monitoring.

Non-contact probes can measure shaft movement without mechanical contact, supporting long-term monitoring in suitable hydroelectric generating equipment.

4. Industrial Compressors

Centrifugal and other high-speed compressors often require shaft vibration and position monitoring. Abnormal vibration may be associated with bearing wear, rotor imbalance, alignment problems, or other mechanical conditions.

The PR6424 series can provide measurement signals for compatible compressor protection and condition monitoring systems.

5. Pumps

Large industrial pumps used in power generation, water treatment, and process plants may require continuous monitoring of shaft movement.

The sensor can be used in suitable pump installations to measure relative shaft displacement and support maintenance assessments.

6. Industrial Fans

Large rotating fans may experience vibration caused by imbalance, bearing deterioration, mechanical looseness, or changes in operating conditions.

When installed at an appropriate measurement point, the sensor can provide displacement information for a compatible monitoring system.

Installation and System Integration

Correct installation is essential for obtaining reliable measurement results. Probe position, target material, air gap, cable routing, and signal converter compatibility all influence measurement performance.

1. Confirm the Sensor Configuration

Before installation, verify the complete model number PR6424/013-100 and check the sensor’s physical configuration.

Confirm the cable length, connector type, cable protection, mounting thread, and converter compatibility. Do not assume that every PR6424 probe uses the same cable arrangement.

2. Select the Correct Measurement Position

The probe should be installed at a suitable measurement location where the target shaft surface is accessible and provides the required clearance.

The PR6424 series is designed for measurement against ferromagnetic steel targets. The shaft material and surface condition should therefore be checked before installation.

Metallic objects near the sensing tip can influence the electromagnetic field and affect measurement accuracy. Maintain the clearance required by the manufacturer.

3. Set the Initial Air Gap

The PR6424 series has a nominal center air gap of approximately 2.7 mm. The actual installation gap should be established using the manufacturer’s calibration procedure and the compatible signal converter.

Incorrect air-gap adjustment can reduce the available linear measurement range or result in inaccurate readings.

4. Install the Probe Securely

The probe must be mounted securely to prevent movement caused by machinery vibration. Where the configuration uses an M18 × 1.5 threaded body, verify the mounting thread and mechanical dimensions before fitting.

Tighten the mounting hardware according to the applicable installation instructions. Avoid excessive force that could damage the sensor body or cable connection.

5. Route and Protect the Cable

Route the sensor cable away from high-temperature surfaces, moving machinery, and sources of electrical interference.

Maintain the minimum bending radius specified for the particular cable construction. Avoid sharp bends, excessive tension, and damage to the cable insulation.

If the cable uses an armored section, ensure that the protection is not crushed or bent beyond its permitted radius.

6. Connect the Signal Converter

Connect the sensor to the compatible extension cable and signal converter according to the manufacturer’s wiring arrangement.

The probe, extension cable, and converter should be treated as a matched measurement system. Incorrect combinations can affect calibration, sensitivity, and measurement accuracy.

7. Calibrate and Verify the Measurement

After installation, check the probe gap and verify the measurement output across the required operating range.

Confirm that the monitoring instrument displays plausible shaft displacement values and that the signal remains stable under normal operating conditions.

Document the final mounting position, calibration information, cable arrangement, and monitoring-channel settings for future maintenance.

Compatible System Components

The PR6424/013-100 normally operates with additional measurement and monitoring equipment.

The probe, cable, converter, and monitoring equipment must be selected as a compatible system. Similar connector appearances do not necessarily indicate electrical compatibility.

Alternative Models and Replacement Considerations

The PR6424 series includes multiple sensor configurations. A replacement should be selected according to the original measurement requirements rather than the sensor-head diameter alone.

Before replacing the PR6424/013-100, check:

• Complete model and suffix.
• Sensor-head diameter.
• Mounting thread and mechanical dimensions.
• Cable length and construction.
• Connector and adaptor arrangement.
• Compatible signal converter.
• Sensitivity and measurement range.
• Target material and shaft diameter.
• Operating temperature and environmental conditions.
• Monitoring-system calibration and channel configuration.

A sensor with the same 16 mm head diameter is not necessarily a direct replacement. Cable and converter compatibility are particularly important for maintaining measurement accuracy.

Key Advantages

Non-Contact Measurement

The sensor measures shaft displacement without physical contact, avoiding mechanical wear at the sensing interface.

Continuous Shaft Monitoring

It can provide measurement signals for continuous monitoring of rotating machinery when connected to a suitable converter and monitoring system.

Multiple Measurement Applications

The PR6424 series supports radial and axial displacement, position, eccentricity, and suitable speed-related measurement arrangements.

High Measurement Sensitivity

The published series sensitivity of 4 V/mm and linearity of up to ±1.5% support accurate displacement measurement when the system is correctly installed and calibrated.

Industrial Machinery Applications

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

Compact 16 mm Sensing Head

The 16 mm probe design supports installation at suitable machinery measurement points where the required mounting space and clearance are available.

Integration with Machinery Protection Systems

When paired with compatible signal-conditioning equipment, the probe can supply measurement information to machinery monitoring and protection systems.

Technical FAQs

1. What is the EPRO PR6424/013-100?

It is a 16 mm non-contact eddy current displacement sensor designed for monitoring shaft vibration, position, and displacement in rotating machinery.

2. What is the sensor-head diameter?

The nominal sensor-head diameter is 16 mm.

3. What is the measurement principle?

The sensor uses eddy current technology. Its electromagnetic field interacts with a conductive metallic target, and changes in the probe’s electrical characteristics are used to determine the distance between the sensor and the target.

4. What is the typical sensitivity?

The published PR6424 series sensitivity is 4 V/mm, equivalent to approximately 101.6 mV/mil, with a specified linearity of up to ±1.5%.

5. What is the static measurement range?

The published series static measurement range is ±2.0 mm. The usable range in an installation depends on the initial air gap and the complete measurement-system configuration.

6. What is the nominal air gap?

The nominal center air gap is approximately 2.7 mm. Final adjustment should follow the manufacturer’s installation and calibration procedure.

7. Can the sensor measure shaft vibration?

Yes. When installed at a suitable position and connected to a compatible converter, the sensor can measure dynamic shaft displacement associated with vibration.

8. Does the sensor connect directly to a PLC?

It should not be assumed to connect directly to a standard PLC analog input. A compatible signal converter or machinery monitoring interface is normally required.

9. What is the sensor weight?

The supplied product weight is 0.2 kg. The published PR6424 series reference weight is approximately 200 grams for the sensor with a 1-meter cable and without armor.

10. What should be checked before purchasing a replacement?

Verify the complete model suffix, cable length, connector type, mounting arrangement, sensor-head diameter, and signal converter compatibility. These details are essential for maintaining the original measurement characteristics.

Procurement and Maintenance Recommendations

When purchasing the EPRO PR6424/013-100, confirm that the supplied product matches the complete catalog number. The PR6424 family contains different cable, connector, mounting, and configuration options that should not be treated as interchangeable without technical verification.

For replacement projects, compare the original sensor’s physical dimensions, cable arrangement, converter compatibility, and calibration requirements. Request clear product photographs and nameplate information when sourcing new-old-stock, surplus, or refurbished equipment.

During maintenance, inspect the probe tip, threaded mounting section, cable insulation, connector, and protective covering. Look for mechanical damage, contamination, corrosion, or signs of excessive cable bending.

After replacement, verify the initial air gap and recalibrate the measurement channel as required. Compare the new readings with the established machinery baseline before returning the monitoring channel to normal service.

For critical turbines and compressors, sensor replacement should be coordinated with the machinery monitoring and protection-system maintenance procedures. Correct calibration and signal verification help preserve the reliability of shaft displacement and vibration measurements.

Conclusion

The EPRO PR6424/013-100 16 mm Eddy Current Sensor is a non-contact measurement probe designed for monitoring shaft displacement, vibration, position, and eccentricity in critical rotating machinery. Its 16 mm sensing head and eddy current operating principle make it suitable for integration into compatible machinery condition monitoring and protection systems.

With a typical PR6424 series sensitivity of 4 V/mm and a static measurement range of ±2.0 mm, the sensor supports precision displacement monitoring when correctly installed and calibrated. For maintenance and replacement applications, verifying the complete model suffix, cable configuration, connector, and signal converter compatibility is essential.