Product Overview

The Epro PR6424/009-000 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 industrial machinery protection and condition monitoring applications.

Manufactured under the EPRO product line associated with Emerson, the PR6424 sensor is designed to measure shaft vibration, radial and axial displacement, shaft position, eccentricity, and rotational speed-related signals. It is commonly used in applications involving steam turbines, gas turbines, hydro turbines, compressors, pumps, and industrial fans.

Unlike contact-type measurement devices, an eddy current sensor measures the distance between its probe tip and a conductive target without physically touching the rotating shaft. This non-contact measurement method allows continuous monitoring while reducing mechanical wear at the sensing point.

The PR6424/009-000 has a nominal sensor head diameter of 16 mm and a supplied product weight of approximately 0.2 kg. Its measurement principle is based on changes in the electromagnetic field generated by the probe when a suitable metallic target approaches or moves away from the sensor tip.

When paired with a compatible signal converter, the sensor can provide measurement signals for machinery monitoring and protection systems. These signals can be used to evaluate shaft movement, detect abnormal vibration, and identify changes in the mechanical condition of rotating equipment.

For industrial maintenance teams, the PR6424/009-000 is relevant to installations where accurate shaft displacement measurement and continuous machinery condition monitoring are important.

Technical Specifications

Note: The technical performance values above describe the PR6424 16 mm sensor family. Confirm the exact cable, connector, temperature rating, and configuration of the PR6424/009-000 before installation.

Function and Working Principle

The PR6424/009-000 uses eddy current technology to measure the distance between the sensor tip and a conductive metallic target. Its primary function is to detect changes in the position of a rotating shaft and convert these changes into an electrical measurement signal through a compatible converter.

1. Non-Contact Eddy Current Measurement

The sensor contains a coil that generates an alternating electromagnetic field near the probe tip. When a conductive metallic target, such as a suitable steel shaft, enters this field, electrical currents known as eddy currents are induced in the target surface.

These currents influence the electromagnetic characteristics of the probe coil. As the distance between the sensor and target changes, the electrical response of the sensing circuit also changes.

A compatible signal converter processes this response and produces an output related to the measured gap.

Because the sensor does not need to touch the shaft, it can continuously monitor rotating equipment without introducing mechanical contact at the measurement point.

2. Shaft Displacement Measurement

The PR6424 series is designed to measure shaft displacement within its specified measurement range.

In rotating machinery, shaft movement may result from mechanical imbalance, bearing wear, alignment problems, thermal expansion, or changes in operating load.

The sensor measures the relative distance between the probe and the shaft surface. When the shaft moves, the sensor output changes accordingly.

Monitoring these variations can help maintenance personnel identify abnormal shaft movement before it develops into a more serious mechanical problem.

3. Shaft Vibration Monitoring

Dynamic shaft vibration is an important indicator of rotating machinery condition.

The PR6424 sensor can detect changes in shaft position over time. When connected to a compatible monitoring system, these measurements can be used to evaluate vibration amplitude and identify abnormal operating patterns.

For example, excessive shaft vibration may indicate rotor imbalance, mechanical looseness, misalignment, or deterioration of supporting components.

The sensor provides measurement data, while the monitoring system performs the necessary signal processing, alarm evaluation, and condition assessment.

4. Shaft Position and Eccentricity Measurement

In addition to dynamic vibration, the PR6424 series supports static shaft position measurement.

Static position measurements are useful for monitoring shaft movement relative to the machine housing or bearing structure. They can help detect changes in shaft alignment, bearing clearance, or mechanical positioning.

Eccentricity measurements can also be used to evaluate uneven shaft geometry or shaft movement during rotation.

5. Signal Conversion

The sensor probe is one part of a complete measurement system. It normally works with an extension cable and a compatible signal converter.

The converter supplies the required excitation and processes the probe’s electrical response into a usable measurement signal.

The resulting output can be connected to a machinery monitoring system, protection device, or other compatible measurement equipment.

The correct converter, cable arrangement, and electrical configuration must be confirmed before commissioning.

Role in Industrial Machinery Protection Systems

The PR6424/009-000 can serve as a measurement component in industrial machinery protection and condition monitoring systems.

Rotating equipment often operates continuously under changing temperatures, pressures, speeds, and mechanical loads. Continuous shaft monitoring helps operators understand how equipment behaves under these operating conditions.

Turbine Monitoring

Steam and gas turbines contain high-speed rotating assemblies that require accurate monitoring of shaft movement and vibration.

Eddy current probes can be installed near suitable shaft measurement locations to monitor radial or axial displacement.

The measurement signals can help identify abnormal rotor movement and support machinery protection strategies.

Compressor Condition Monitoring

Industrial compressors are commonly used in chemical plants, refineries, gas processing facilities, and manufacturing systems.

Changes in shaft vibration or position may indicate developing mechanical problems.

The PR6424 series can provide non-contact shaft measurement signals for compatible compressor monitoring installations.

Pump Monitoring

Large industrial pumps operate under changing hydraulic loads and mechanical conditions.

Shaft vibration and displacement monitoring can help maintenance personnel identify abnormal operation, bearing deterioration, and mechanical instability.

Fan and Blower Monitoring

Industrial fans and blowers are widely used in ventilation, cooling, combustion, and process air systems.

Continuous vibration monitoring can help identify imbalance, misalignment, and other mechanical conditions that may affect equipment reliability.

Integration with Machinery Protection Equipment

The sensor’s output is processed by a compatible signal converter before being used by monitoring equipment.

Depending on the installed system, the resulting signals may be used for vibration monitoring, shaft position measurement, alarm generation, and machinery protection functions.

The complete measurement chain must be configured correctly to ensure reliable readings.

Industrial Applications

1. Steam Turbines

Steam turbines are used in power generation and industrial energy systems. Their rotating shafts operate under demanding mechanical and thermal conditions.

The PR6424 sensor can measure shaft displacement and vibration without physical contact. This information can support the monitoring of rotor behavior and help identify abnormal vibration conditions.

2. Gas Turbines

Gas turbines are used in power plants, industrial facilities, and mechanical drive applications.

Continuous shaft monitoring is important because abnormal vibration or displacement may indicate mechanical problems that require investigation.

A suitable PR6424 measurement system can provide shaft-related measurement signals for compatible turbine protection equipment.

3. Hydro Turbines

Hydro turbines operate in power generation facilities where monitoring rotor movement and mechanical stability is important.

Eddy current measurement technology can be used to monitor shaft position and vibration in suitable hydro turbine installations.

4. Industrial Compressors

Centrifugal and other large industrial compressors require reliable monitoring to maintain stable operation.

Shaft displacement measurements can help identify changes in rotor behavior, bearing conditions, and mechanical alignment.

The PR6424 series is designed for applications involving large rotating shafts, with a specified minimum shaft diameter of 80 mm.

5. Industrial Pumps

Large pumps are used in water treatment, chemical processing, oil and gas production, and power generation.

The sensor can provide non-contact measurement of shaft movement in compatible pump installations.

6. Industrial Fans

Fans and blowers are used in ventilation, cooling, and process-air systems.

Monitoring shaft vibration can help detect imbalance, looseness, and other mechanical abnormalities.

Installation and System Integration

Correct installation is essential for measurement accuracy and reliable machinery monitoring.

1. Verify Sensor Compatibility

Before installation, confirm that the PR6424/009-000 is compatible with the intended signal converter and extension cable.

Check the complete model number, connector configuration, cable length, and applicable system documentation.

Do not assume that all PR6424 probes use identical connection arrangements.

2. Select an Appropriate Measurement Location

The probe should be installed at a suitable measurement point near the shaft surface.

The mounting location should provide a stable mechanical reference and allow the sensor to measure the intended shaft movement.

The shaft surface should be suitable for eddy current measurement and should meet the target-material requirements.

3. Set the Correct Air Gap

The PR6424 series has a nominal center air gap of approximately 2.7 mm.

Correct probe positioning is essential because the sensor operates within a defined linear measurement range.

An incorrect initial gap may reduce measurement accuracy or cause the sensor to operate outside its specified linear region.

The actual installation gap should be established according to the manufacturer’s installation procedure and the compatible converter requirements.

4. Check Probe Mounting

Ensure that the sensor is securely mounted and protected against unwanted movement.

Loose mounting hardware may introduce measurement errors or affect the reliability of vibration readings.

The installation should also provide adequate clearance from nearby metallic structures that could interfere with the electromagnetic measurement field.

5. Connect the Extension Cable and Converter

Connect the probe to the compatible extension cable and signal converter using the correct connector arrangement.

Check cable routing, connector condition, and electrical continuity.

Avoid placing sensor cables alongside high-power conductors where electromagnetic interference could affect measurement quality.

6. Configure the Monitoring System

After installation, configure the monitoring equipment according to the sensor and converter specifications.

The system should use the correct sensitivity, measurement range, alarm settings, and signal scaling.

Where shaft vibration and position are monitored simultaneously, verify that the measurement channels are configured for their intended functions.

7. Perform Initial Testing

After completing the installation, check the sensor signal under static conditions before starting the machine.

Verify the initial air gap, signal stability, converter operation, and monitoring-channel response.

During commissioning, compare measurement behavior with the expected operating conditions and investigate any abnormal readings.

Compatible System Components

The PR6424/009-000 is normally used as part of a complete eddy current measurement system.

The components listed above are examples of equipment used in PR6424 measurement installations. They are not necessarily included with the sensor.

Always verify the converter and cable requirements for the exact sensor configuration.

Alternative Models and Replacement Considerations

The PR6424 belongs to the 16 mm EPRO eddy current sensor family. Other models in the same series may provide similar measurement functions but can differ in cable length, probe construction, connector arrangement, and installation details.

Before replacing the PR6424/009-000, check:

• Complete sensor model and suffix.
• Sensor head diameter.
• Probe body and mounting thread.
• Cable length and cable construction.
• Connector type and pin arrangement.
• Compatible signal converter.
• Sensitivity and measurement range.
• Operating temperature requirements.
• Target material and shaft diameter.
• Monitoring system input requirements.

A sensor with the same 16 mm head diameter is not automatically a direct replacement. The entire measurement chain must be checked.

Key Advantages

Non-Contact Measurement

The sensor measures shaft movement without physical contact, reducing wear at the measurement point.

Continuous Shaft Monitoring

It supports continuous measurement of shaft displacement and vibration when integrated with suitable monitoring equipment.

Suitable for Critical Rotating Machinery

The PR6424 series is designed for applications involving turbines, compressors, pumps, and fans.

High Measurement Sensitivity

The series provides a nominal sensitivity of 4 V/mm, supporting the measurement of small changes in shaft position.

Static and Dynamic Measurement

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

Industrial Temperature Capability

The PR6424 family is designed for demanding machinery environments. The exact operating temperature limit should be checked against the applicable model specification.

Integration with Machinery Monitoring Systems

When paired with a compatible converter, the sensor can provide measurement signals for industrial machinery monitoring and protection equipment.

Technical FAQs

1. What is the Epro PR6424/009-000?

The Epro PR6424/009-000 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 probe generates an electromagnetic field, and changes in the distance to a conductive target affect the electrical response of the sensing coil.

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

The documented series specification provides a static measurement range of ±2.0 mm and a dynamic measurement range of 0 to 1,000 μm.

5. What is the sensitivity?

The nominal sensitivity is 4 V/mm, equivalent to approximately 101.6 mV/mil.

6. Does the sensor require a signal converter?

Yes. The probe is normally used with a compatible signal converter that processes the sensor response and provides a measurement output for the monitoring system.

7. What equipment can use this sensor?

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

8. What target material is suitable?

The PR6424 series is specified for ferromagnetic steel targets, with 42CrMo4 identified as a standard target material.

9. What should be checked if the measurement signal is unstable?

Check the probe mounting, initial air gap, cable condition, connector contacts, converter compatibility, grounding, target surface, and monitoring-channel configuration.

10. Can another PR6424 model replace the PR6424/009-000?

Possibly, but the complete model configuration must be compared. Cable length, connector type, probe construction, and converter compatibility should all be verified before replacement.

Procurement and Maintenance Recommendations

When purchasing the Epro PR6424/009-000, verify the complete model number and confirm that the sensor matches the existing machinery monitoring system.

For replacement projects, pay particular attention to the sensor’s cable configuration and connector arrangement. These details can affect whether the probe can be connected directly to the existing extension cable and converter.

For used or surplus equipment, inspect the probe body, sensing tip, cable insulation, connectors, and mounting threads. Request clear photographs of the product label and connector end where possible.

During routine maintenance, inspect cable routing and mounting hardware. Check for damaged insulation, loose connectors, excessive vibration at the mounting point, and contamination around the sensor installation.

If the measurement signal changes unexpectedly, verify the mechanical installation and electrical signal chain before replacing the probe. An incorrect air gap, damaged cable, incompatible converter, or unsuitable target surface may produce abnormal readings.

For critical turbine and compressor installations, follow the machinery manufacturer’s monitoring requirements and the applicable sensor and converter documentation.

Conclusion

The Epro PR6424/009-000 16 mm Eddy Current Sensor is designed for non-contact measurement of shaft displacement and vibration in industrial rotating machinery. With a 16 mm sensor head, it belongs to the PR6424 family used in turbine, compressor, pump, and fan monitoring applications.

The series provides a nominal sensitivity of 4 V/mm, a static measurement range of ±2.0 mm, and a dynamic measurement range of up to 1,000 μm. When correctly installed and paired with a compatible signal converter, the sensor can provide important measurement data for industrial machinery condition monitoring and protection systems.

For procurement and replacement, confirming the exact probe configuration, cable connection, converter compatibility, and installation requirements is essential to maintaining reliable measurement performance.