Product Overview

The EPRO PR6424/010-040 16 mm Eddy Current Sensor is a non-contact displacement measurement device designed for monitoring the condition and operating performance of rotating industrial machinery. It belongs to the PR6424 series of 16 mm eddy current sensors, developed for applications that require reliable measurement of shaft vibration, displacement, position, and eccentricity.

Manufactured under the EPRO product range associated with Emerson, the PR6424 sensor is used in machinery protection and condition-monitoring systems. Typical applications include steam turbines, gas turbines, hydro turbines, compressors, pumps, and industrial fans. These machines often operate under demanding mechanical and thermal conditions, making continuous shaft monitoring important for equipment protection and maintenance planning.

Unlike contact-based measurement devices, an eddy current sensor measures the distance between its sensing tip and a conductive target without physically touching the rotating shaft. This non-contact principle allows the sensor to monitor shaft movement while minimizing mechanical wear caused by the measurement process.

The PR6424/010-040 has a 16 mm sensor head diameter and is designed to work with compatible signal converters and machinery-monitoring equipment. Its measurement characteristics support both static shaft-position monitoring and dynamic vibration measurement.

The sensor can provide information about changes in shaft position, vibration amplitude, and other mechanical conditions. When integrated into a suitable monitoring system, these measurements help maintenance engineers identify abnormal operating behavior and assess the condition of critical rotating equipment.

With a listed weight of approximately 0.2 kg, the PR6424/010-040 is a compact sensing component for industrial machinery-monitoring installations. Its actual cable configuration, connector arrangement, mounting dimensions, and compatibility should be verified using the complete model designation before installation or replacement.

Technical Specifications

Note: The weight is consistent with the manufacturer’s approximate figure for the sensor and 1 m cable without armor. The complete ordering code determines the specific cable and connector configuration. Confirm the applicable technical documentation before selecting a replacement.

Function and Working Principle

The PR6424/010-040 operates according to the eddy current measurement principle. It generates an electromagnetic field at the sensor tip and detects changes in that field caused by the distance between the sensor and a conductive target.

When installed near a rotating shaft, the sensor continuously responds to changes in the gap between its tip and the shaft surface. These changes are converted into an electrical measurement signal by the compatible sensor system.

1. Non-Contact Displacement Measurement

The sensor is installed with its sensing face directed toward a suitable conductive shaft surface. As the shaft moves, the distance between the sensor and the target changes.

The resulting variation in the electromagnetic field provides information about shaft displacement. Because the sensor does not need to touch the shaft, it can monitor movement without introducing mechanical contact between the probe and the rotating component.

This is particularly useful in high-speed machinery, where direct mechanical contact would be unsuitable for continuous displacement measurement.

2. Eddy Current Detection

An alternating electromagnetic field is generated by the sensor coil. When a conductive target approaches the sensor, eddy currents are induced in the target material.

These currents influence the electromagnetic characteristics of the sensor coil. The resulting change is related to the distance between the sensor tip and the target surface.

A compatible signal converter processes the sensor response and produces a usable measurement output. The output can then be supplied to a machinery-monitoring or protection system.

3. Shaft Vibration Measurement

Shaft vibration is an important indicator of rotating-machine condition. Excessive vibration may be associated with rotor imbalance, misalignment, bearing problems, mechanical looseness, or other operating abnormalities.

The PR6424 sensor measures the dynamic movement of the shaft relative to the sensor mounting position. When used with compatible monitoring equipment, the resulting signal can be analyzed to determine vibration amplitude and changes in shaft movement.

The sensor’s dynamic measurement range extends from zero to 1,000 μm, according to the manufacturer’s specification.

4. Shaft Position and Displacement Monitoring

In addition to dynamic vibration, the PR6424 can measure static shaft position within its specified measuring range.

Static displacement information is useful for monitoring the position of rotating components and identifying changes in the mechanical relationship between the shaft and surrounding structures.

The specified static measurement range is ±2.0 mm. Correct positioning and calibration are essential to obtain meaningful readings.

5. Signal Conversion and Monitoring

The PR6424 probe is part of a measurement system rather than a complete standalone monitoring instrument. A compatible signal converter is required to condition the sensor response and provide an output suitable for monitoring equipment.

The converter, extension cable where applicable, and monitoring channel must be matched to the probe’s electrical and mechanical configuration.

Role in Industrial Machinery Protection Systems

The EPRO PR6424/010-040 can serve as a sensing component in machinery condition-monitoring and protection systems. Its measurements help monitoring equipment evaluate the mechanical behavior of critical rotating assets.

Turbine Shaft Monitoring

Steam, gas, and hydro turbines operate with rotating shafts that must remain within acceptable mechanical limits. Shaft vibration and displacement measurements provide information about rotor movement during startup, normal operation, load changes, and shutdown.

The PR6424 can be installed at suitable measurement locations to monitor radial or axial shaft movement, depending on the machinery design.

Compressor Condition Monitoring

Industrial compressors often operate continuously in demanding process environments. Changes in shaft vibration or position may indicate developing mechanical problems.

A non-contact sensor provides a way to monitor shaft movement without placing a contact probe against the rotating surface. The measurement signal can be incorporated into a compatible machinery-monitoring system.

Pump Monitoring

Large industrial pumps are used in power generation, chemical processing, water treatment, and other industries. Their rotating components may be exposed to changing loads and operating conditions.

Shaft displacement measurements can help maintenance personnel assess mechanical behavior and identify changes that require further inspection.

Fan and Blower Monitoring

Industrial fans and blowers may experience vibration caused by imbalance, mechanical wear, or mounting problems. Where the shaft geometry and monitoring arrangement are suitable, an eddy current sensor can provide useful displacement information.

Integration with Monitoring Systems

The sensor can be used with compatible EPRO/Emerson signal-conditioning and machinery-monitoring equipment. The exact converter and monitoring channel must be selected according to the sensor configuration and the required measurement function.

A complete installation should consider the probe, cable, connector, converter, monitoring module, and system configuration as a coordinated measurement chain.

Industrial Applications

1. Steam Turbine Monitoring

Steam turbines are important assets in power generation and industrial energy systems. Continuous shaft monitoring helps operators observe rotor behavior and identify abnormal vibration or displacement.

The PR6424 can be used at suitable measurement points to support shaft vibration and position monitoring.

2. Gas Turbine Protection

Gas turbines operate at high speeds and under significant thermal and mechanical stress. Monitoring shaft movement provides information that can support machinery protection and condition assessment.

The sensor’s non-contact operating principle makes it suitable for appropriately engineered turbine-monitoring installations.

3. Hydro Turbine Monitoring

Hydro turbines are used in hydroelectric power plants and may experience changing mechanical loads during operation. Shaft displacement and vibration measurements help operators evaluate rotor behavior.

The PR6424 can be incorporated into a suitable monitoring arrangement where its measuring characteristics match the machine requirements.

4. Industrial Compressor Monitoring

Compressors are used in petrochemical plants, refineries, gas processing facilities, and manufacturing operations. Abnormal shaft movement may be associated with mechanical degradation or changes in operating conditions.

The sensor can provide measurement signals for compatible monitoring equipment to support condition-based maintenance.

5. Centrifugal Pump Monitoring

Large centrifugal pumps often operate continuously and are essential to process reliability. Shaft vibration monitoring can help identify changes in mechanical performance.

When installed at suitable measurement locations, the PR6424 can provide non-contact shaft displacement information.

6. Industrial Fan and Blower Systems

Fans and blowers are widely used in ventilation, combustion-air supply, cooling, and industrial process systems. Monitoring shaft movement can help maintenance teams evaluate mechanical condition and investigate unusual vibration.

The sensor should be selected according to shaft size, target material, installation geometry, and the required measurement range.

Installation and System Integration

Correct installation is essential for obtaining stable measurement signals and reliable machinery-monitoring results.

1. Verify Sensor Compatibility

Before installation, confirm that the PR6424/010-040 is compatible with the intended signal converter and monitoring equipment.

Check the full model designation, connector arrangement, cable configuration, and sensor characteristics. Do not assume that all PR6424 variants have identical cable lengths or connection arrangements.

2. Select a Suitable Measurement Location

The sensor should be mounted at a location that provides a stable and representative measurement of shaft movement.

The target surface must be suitable for eddy current measurement. The manufacturer’s standard target material is ferromagnetic steel, with 42CrMo4 specified as the standard reference material.

The recommended minimum shaft diameter is 80 mm. Confirm that the actual shaft dimensions and material meet the requirements of the selected measurement arrangement.

3. Set the Initial Air Gap

The nominal center air gap is approximately 2.7 mm. The actual installation gap should be established according to the applicable sensor and converter instructions.

Incorrect sensor positioning may reduce the available measurement range or cause inaccurate readings. The gap should be checked during installation and commissioning.

4. Secure the Sensor Mechanically

The sensor must be mounted securely so that the probe does not move relative to the machinery housing during operation.

Follow the manufacturer’s mechanical installation instructions and use suitable mounting hardware. Avoid excessive mechanical stress on the sensor body, cable, and connector.

5. Route and Protect the Cable

The cable should be routed to prevent abrasion, excessive bending, crushing, and exposure to unsuitable temperatures or contaminants.

Keep sensor cables away from high-interference power wiring where required by the installation design. Observe the cable’s permitted bending radius and temperature limits.

The exact cable arrangement should be checked against the ordering code and supplied product configuration.

6. Connect the Signal Converter

Connect the sensor to a compatible signal converter using the correct cable and connector arrangement.

The converter processes the sensor signal and supplies a conditioned output to the monitoring system. Incorrect converter selection or wiring can lead to unreliable readings or an inoperative measurement channel.

7. Commission and Verify the Measurement

After installation, verify the initial gap, signal response, channel configuration, and measurement scaling.

Compare the sensor output with the expected shaft position and vibration conditions. Record the installation details and calibration information for future maintenance.

Compatible System Components

The PR6424/010-040 is normally used as part of a complete machinery-monitoring arrangement. The following components may be required depending on the application.

A signal converter and monitoring module are not automatically included with the sensor. Confirm the supplied items and system requirements before procurement.

Alternative Models and Replacement Considerations

The PR6424 is part of a broader family of eddy current displacement sensors. Other models may have different sensor diameters, cable configurations, mounting arrangements, or operating characteristics.

Before selecting an alternative, compare:

• Sensor head diameter.
• Sensor thread and mounting arrangement.
• Static and dynamic measurement ranges.
• Sensitivity and linearity.
• Target material and shaft diameter.
• Operating temperature.
• Cable length and cable construction.
• Connector and adapter configuration.
• Signal converter compatibility.
• Monitoring system input requirements.

A sensor with a different diameter or similar model number is not automatically interchangeable. Replacing a probe may require checking the converter, cable, mounting dimensions, measurement scaling, and monitoring-channel configuration.

Key Advantages

Non-Contact Measurement

The PR6424 measures shaft displacement without physical contact with the rotating target. This reduces mechanical wear associated with contact-based measurement methods.

16 mm Sensor Head

The 16 mm sensing diameter is designed for machinery-monitoring applications involving larger rotating shafts.

Static and Dynamic Measurement

The sensor supports static shaft-position measurements and dynamic displacement measurements, allowing it to contribute to different machinery-monitoring functions.

Defined Sensitivity

The specified sensitivity is 4 V/mm, with linearity of no more than ±1.5% under the manufacturer’s stated conditions.

Industrial Machinery Applications

The PR6424 series is designed for use with critical rotating equipment such as turbines, compressors, pumps, and fans.

Industrial Temperature Capability

The December 2024 specification sheet gives an operating temperature range of -35 to 150°C. The actual permitted conditions should be checked against the exact sensor configuration and installation requirements.

Compact Construction

With a listed weight of approximately 0.2 kg, the sensor is suitable for installations where a compact probe and cable assembly are required.

Technical FAQs

1. What is the EPRO PR6424/010-040?

The EPRO PR6424/010-040 is a 16 mm eddy current displacement sensor designed for non-contact measurement of shaft vibration, displacement, 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 electromagnetic induction and eddy current technology. Changes in the distance between the sensor tip and a conductive target alter the sensor’s electromagnetic response.

4. What is the static measurement range?

The manufacturer’s PR6424 specification identifies a static measurement range of ±2.0 mm.

5. What is the dynamic measurement range?

The specified dynamic range is 0 to 1,000 μm.

6. What is the sensitivity of the PR6424 sensor?

The specified sensitivity is 4 V/mm, with linearity of ≤ ±1.5%.

7. What material should be used as the measurement target?

The standard target material is ferromagnetic steel, with 42CrMo4 used as the manufacturer’s reference material.

8. Does the sensor require a signal converter?

Yes. The PR6424 is part of a measurement system and requires a compatible signal converter to condition its sensor signal for use by monitoring equipment.

9. What machinery can use the PR6424/010-040?

Typical applications include steam turbines, gas turbines, hydro turbines, compressors, pumps, and industrial fans, provided the installation meets the sensor’s technical requirements.

10. What is the weight of the sensor?

The supplied listing weight is 0.2 kg. The manufacturer’s specification gives an approximate weight of 200 grams for the sensor with a 1 m cable and without armor.

11. Can the PR6424/010-040 replace another PR6424 model?

Not automatically. Different variants may have different cable lengths, connector arrangements, sensor lengths, and mechanical configurations. Confirm the complete model number and system compatibility before replacement.

Procurement and Maintenance Recommendations

When purchasing the EPRO PR6424/010-040, verify the complete model number and confirm that the supplied sensor matches the intended monitoring system. Pay particular attention to the cable configuration, connector type, mounting arrangement, and compatibility with the signal converter.

For replacement projects, compare the existing probe’s physical dimensions, initial air gap, target material, measurement range, and electrical characteristics. A sensor that belongs to the same PR6424 family may still have a different ordering configuration.

During maintenance, inspect the sensor tip, cable insulation, connector, mounting hardware, and cable routing. Look for signs of mechanical damage, abrasion, loose mounting, or contamination.

If the monitoring signal becomes unstable, check the complete measurement chain rather than replacing the sensor immediately. Potential causes may include incorrect initial gap, cable damage, connector problems, unsuitable target material, converter issues, or monitoring-channel configuration errors.

Keep installation records, model identification, calibration information, and converter settings available for future maintenance. These records help reduce troubleshooting time and support consistent machinery-monitoring performance.

Conclusion

The EPRO PR6424/010-040 16 mm Eddy Current Sensor is a non-contact displacement sensor designed for shaft vibration and position monitoring in critical rotating machinery. Its 16 mm sensing head, 4 V/mm sensitivity, ±2.0 mm static measurement range, and 0–1,000 μm dynamic measurement range make it suitable for appropriately configured turbine, compressor, pump, and fan monitoring applications.

For reliable operation, the sensor must be matched with a compatible signal converter, correctly installed at the specified measurement gap, and used with a suitable target material. Accurate model identification and verification of the cable and connector configuration are especially important when sourcing replacement sensors for existing machinery protection systems.