Product Overview

The Epro PR6424/107-000 16 mm Eddy Current Sensor is a non-contact displacement measurement probe designed for monitoring the condition and operating behavior of rotating machinery. It belongs to the PR6424 sensor family developed for machinery protection and condition monitoring applications.

Manufactured under the EPRO product line associated with Emerson, the PR6424 series is commonly used in critical equipment such as steam turbines, gas turbines, hydro turbines, compressors, pumps, and industrial fans. Its primary purpose is to measure shaft movement without requiring physical contact between the sensor tip and the rotating target.

In rotating machinery, shaft displacement and vibration can provide important information about equipment condition. Changes in shaft position may indicate mechanical imbalance, misalignment, bearing problems, excessive vibration, or other abnormal operating conditions. A proximity sensor installed at the appropriate measurement point can continuously detect these movements and provide a signal for a compatible monitoring system.

The PR6424 uses eddy current technology to measure the distance between its sensing tip and a conductive target. Its 16 mm sensing-head design is intended for applications involving relatively large rotating shafts. When connected to a compatible signal converter, the sensor forms part of a measurement system capable of monitoring both static shaft position and dynamic displacement.

The sensor is particularly relevant to machinery protection systems where continuous monitoring is required. It can provide measurement information used by operators and maintenance engineers to evaluate machine behavior, identify developing problems, and support preventive maintenance strategies.

The listed product weight is approximately 0.2 kg. This is consistent with the PR6424 series reference weight of approximately 200 grams for a sensor with a 1-meter unarmored cable. However, the exact cable and connector configuration should be verified against the complete PR6424/107-000 ordering specification.

Technical Specifications

Note: The performance figures above describe the PR6424 16 mm sensor family. Exact cable length, connector arrangement, thread configuration, and environmental limits should be confirmed for the PR6424/107-000 variant before installation.

Function and Working Principle

The PR6424/107-000 operates using the eddy current measurement principle. This technology allows the sensor to detect the distance between its sensing tip and a conductive metal target without physical contact.

1. Eddy Current Measurement

The sensor contains an electromagnetic coil located near its sensing tip. When connected to a compatible signal converter, the coil generates a high-frequency electromagnetic field.

When a conductive target, such as a suitable ferromagnetic steel shaft, approaches the sensor, the electromagnetic field induces eddy currents in the target surface. These currents affect the electrical characteristics of the sensor coil.

The resulting change in coil impedance is related to the distance between the probe and the target. The measurement electronics convert this change into a signal representing the measured gap.

Because the measurement does not require mechanical contact, the sensor can monitor rotating shafts without introducing additional friction or physical wear at the sensing point.

2. Shaft Displacement Measurement

One of the main functions of the PR6424 is measuring radial and axial shaft displacement.

Radial displacement refers to movement of the shaft perpendicular to its rotational axis. Axial displacement refers to movement along the shaft’s rotational direction.

Monitoring these movements helps engineers evaluate shaft behavior under operating conditions. Abnormal displacement may be associated with bearing wear, changes in mechanical alignment, excessive loading, or other equipment problems.

3. Vibration Monitoring

The sensor can detect small, rapid changes in the distance between the probe and the rotating shaft. These changes can be used to monitor shaft vibration when the sensor is connected to a suitable measurement and monitoring system.

The PR6424 series has a typical dynamic measurement range of 0–1,000 μm. This allows the system to capture shaft movement within the specified measurement range.

Vibration data can help maintenance teams identify changes in machine behavior and investigate potential mechanical faults before they develop into more serious failures.

4. Position and Eccentricity Monitoring

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

Position monitoring is useful for evaluating shaft location relative to the installed sensor. Eccentricity measurements can also help identify deviations between the shaft’s rotational center and its geometric center.

These measurements are particularly important in large rotating machines where shaft position and movement can influence bearing performance and overall operating stability.

5. Signal Conversion

The PR6424 is a sensing element rather than a complete standalone monitoring instrument. It normally operates with compatible extension cables and signal converters.

A converter conditions the sensor signal and provides an output suitable for the connected machinery monitoring system. The correct converter, cable arrangement, and sensor configuration must be selected as a matched measurement system.

Role in Industrial Machinery Monitoring Systems

The PR6424/107-000 can serve as a measurement component within a machinery protection and condition monitoring installation. Its role is to detect shaft movement and provide measurement information to equipment monitoring electronics.

Turbine Monitoring

Steam, gas, and hydro turbines operate under demanding mechanical and thermal conditions. Continuous shaft monitoring helps operators observe machine movement during startup, normal operation, load changes, and shutdown.

A correctly installed PR6424 sensor can measure shaft displacement and vibration at selected monitoring locations. These measurements can support the detection of abnormal mechanical behavior.

Compressor Protection

Industrial compressors often operate continuously and may be essential to production processes. Shaft vibration and position monitoring can help identify changes associated with bearing wear, imbalance, or mechanical misalignment.

The PR6424 can be incorporated into a suitable compressor monitoring arrangement to provide non-contact shaft measurements.

Pump Condition Monitoring

Large industrial pumps may experience vibration changes caused by bearing deterioration, coupling problems, hydraulic conditions, or mechanical imbalance.

A proximity measurement system can provide information about shaft movement and support maintenance decisions.

Integration with Machinery Monitoring Equipment

The sensor must be connected to a compatible converter and monitoring system. The converter processes the probe signal, while the monitoring equipment evaluates the measurement and provides alarms or other outputs according to the configured protection strategy.

The exact monitoring platform and channel configuration should be confirmed before specifying replacement components.

Industrial Applications

The PR6424 16 mm Eddy Current Sensor is intended for machinery where non-contact shaft measurement is required.

1. Steam Turbines

Steam turbines are used in power generation and industrial energy systems. Shaft vibration and displacement monitoring are important for evaluating mechanical stability during operation.

The PR6424 can be installed at suitable measurement locations to monitor radial or axial shaft movement as part of a compatible protection system.

2. Gas Turbines

Gas turbines operate at high rotational speeds and under demanding temperature and mechanical conditions. Continuous condition monitoring helps operators identify changes in shaft behavior.

A properly selected PR6424 configuration can contribute to shaft displacement and vibration measurement in suitable gas turbine installations.

3. Hydro Turbines

Hydro turbines are used in hydroelectric power generation. Their rotating assemblies require monitoring to help maintain stable operation and protect critical mechanical components.

Non-contact displacement measurement can provide useful information about shaft movement and mechanical condition.

4. Industrial Compressors

Compressors used in petrochemical plants, refineries, and manufacturing facilities may operate continuously under variable process loads.

Shaft vibration and position monitoring can support early investigation of mechanical abnormalities and help reduce the risk of unexpected equipment shutdowns.

5. Industrial Pumps

Large pumps used in water treatment, chemical processing, and industrial production may require continuous monitoring of shaft behavior.

A proximity sensor can measure shaft movement without contacting the rotating surface, making it suitable for appropriately designed machinery monitoring systems.

6. Industrial Fans

Large industrial fans and ventilation systems may experience imbalance, bearing deterioration, or alignment problems.

Shaft vibration measurement can help maintenance personnel identify changes in operating behavior and plan corrective maintenance.

Installation and System Integration

Correct installation is essential for obtaining reliable measurement results from the PR6424/107-000.

1. Confirm the Sensor Configuration

Before installation, verify the complete model number and the sensor’s cable and connector arrangement.

The PR6424 family includes different cable lengths, mounting configurations, and connection options. The suffix /107-000 should be checked against the actual product label and ordering documentation.

Do not assume that every PR6424 sensor has the same cable length or connector type.

2. Select the Correct Measurement Location

The sensor should be installed at a position where it can detect the intended shaft movement.

For radial vibration measurement, the probe is normally positioned to observe the shaft surface perpendicular to the rotational axis. For axial position measurement, the installation geometry must be appropriate for detecting movement along the shaft axis.

The mounting location should provide sufficient mechanical clearance and stable support.

3. Check the Target Surface

The PR6424 series is designed for use with a suitable conductive target, typically ferromagnetic steel.

The target surface should meet the manufacturer’s material and surface requirements. Surface condition, shaft geometry, and target material can influence measurement accuracy.

Avoid installing the probe where the sensing field may be affected by nearby metallic structures.

4. Set the Initial Air Gap

The nominal center air gap for the PR6424 series is approximately 2.7 mm.

The initial gap should be established according to the manufacturer’s installation procedure and the selected converter configuration. Incorrect gap adjustment can reduce the available measurement range or produce inaccurate readings.

5. Connect the Signal Converter

The probe must be connected to a compatible signal converter using the appropriate cable arrangement.

Check the sensor model, extension cable, connector type, and converter compatibility before making connections. A mismatch between system components can result in incorrect output or unreliable measurements.

6. Route and Protect the Cable

The cable should be routed away from excessive heat, mechanical damage, and sources of electromagnetic interference.

Observe the specified minimum bending radius. The PR6424 family documentation distinguishes between armored and unarmored cable configurations, so the correct bending requirement must be selected for the actual assembly.

Secure the cable without placing unnecessary mechanical stress on the sensor connection.

7. Verify the Measurement Signal

After installation, confirm that the sensor and converter produce a stable output at the expected initial gap.

Check the signal over the intended operating range and verify that the monitoring system displays reasonable shaft position and vibration values.

Record the initial measurements as a reference for future condition monitoring.

Compatible System Components

The PR6424/107-000 is normally used as part of a complete eddy current measurement system. Its performance depends on the compatibility of the probe, cable, signal converter, and monitoring equipment.

The components listed above are examples of equipment used in PR6424 measurement systems. They are not necessarily included with the sensor. Exact compatibility should be confirmed using the complete model and system documentation.

Alternative Models and Replacement Considerations

The PR6424 family includes different 16 mm sensor configurations. When replacing the PR6424/107-000, engineers should compare the complete model number rather than selecting another probe based only on its 16 mm diameter.

Before selecting a replacement, verify:

• Sensor head diameter.
• Mounting thread and mechanical dimensions.
• Cable length and cable construction.
• Connector type and pin arrangement.
• Compatible signal converter.
• Sensitivity and linearity.
• Static and dynamic measurement ranges.
• Target material and shaft diameter.
• Operating temperature limits.
• Monitoring system input requirements.

A replacement sensor with the same nominal diameter may still have a different electrical or mechanical configuration. Full system compatibility should be confirmed before installation.

Key Advantages

Non-Contact Measurement

The PR6424 measures shaft movement without physical contact with the rotating target. This avoids mechanical contact between the sensor tip and the shaft during normal operation.

16 mm Sensing Head

The 16 mm sensor-head design is intended for monitoring larger rotating shafts in critical machinery applications.

Static and Dynamic Measurement

The sensor family supports both static shaft position measurement and dynamic displacement measurement, allowing one measurement system to provide information about different aspects of shaft behavior.

High Measurement Sensitivity

The typical sensitivity of 4 V/mm supports the detection of small changes in the sensor-to-target gap when used with a compatible converter.

Industrial Machinery Applications

The PR6424 family is designed for demanding rotating machinery environments, including turbines, compressors, pumps, and fans.

Compact Sensor Construction

The probe uses a stainless steel sleeve and PTFE cable construction. Its compact sensing-head design supports installation at suitable machinery measurement points.

Condition Monitoring Support

Continuous shaft measurement can provide valuable information for machinery condition monitoring and maintenance planning.

Technical FAQs

1. What is the Epro PR6424/107-000?

The Epro PR6424/107-000 is a 16 mm non-contact eddy current sensor designed to measure shaft displacement and vibration in rotating machinery.

2. What is the main function of this sensor?

Its primary function is to measure the distance between the sensor tip and a conductive shaft surface. The measurement can be used to monitor radial displacement, axial position, eccentricity, and vibration through a compatible monitoring system.

3. What is the sensor-head diameter?

The PR6424/107-000 is identified as a 16 mm eddy current sensor.

4. What is the typical sensitivity of the PR6424 series?

The typical sensitivity is 4 V/mm, with a specified linearity of approximately ±1.5% for the documented PR6424 configuration.

5. What is the measurement range?

The PR6424 family has a static measurement range of ±2.0 mm and a dynamic measurement range of 0–1,000 μm. The applicable limits should be checked against the complete sensor and converter configuration.

6. Does the sensor require physical contact with the shaft?

No. It uses eddy current technology to measure shaft movement without touching the rotating surface.

7. What type of target material is required?

The documented PR6424 measurement system is designed for a suitable ferromagnetic steel target. The target material and surface characteristics should meet the manufacturer’s requirements.

8. Can the PR6424 connect directly to a PLC?

The sensor is normally used with a compatible signal converter and monitoring system. A PLC connection requires an appropriate conditioned signal or monitoring-system output. The probe should not be treated as a direct PLC input device without checking the interface requirements.

9. What is the weight of the PR6424/107-000?

The supplied listing weight is 0.2 kg. This is consistent with the PR6424 family reference weight of approximately 200 grams for a sensor with a 1-meter unarmored cable. The exact variant configuration may affect the final weight.

10. What should be checked before replacing this sensor?

Verify the full model number, mounting thread, cable length, connector type, converter compatibility, sensitivity, measurement range, and target material requirements. These details are important for maintaining the accuracy of an existing machinery monitoring system.

Procurement and Maintenance Recommendations

When purchasing the Epro PR6424/107-000, confirm the complete model number and inspect the product label carefully. The PR6424 family includes multiple mechanical and cable configurations, and the suffix can identify important differences in the sensor assembly.

For replacement projects, compare the new sensor with the existing unit. Check the sensing-head diameter, mounting thread, cable construction, connector, and converter compatibility. A sensor with the same nominal diameter is not necessarily a direct replacement.

For used or surplus equipment, request clear photographs of the sensor head, cable, connector, and identification label. Inspect the cable sheath for cuts, crushing, or signs of overheating. Check the threaded mounting section and sensing tip for physical damage.

During installation, maintain the specified air gap and follow the recommended cable-routing and bending requirements. Confirm that the probe is connected to the correct converter and that the measurement output is stable before returning the machinery to service.

For critical rotating equipment, record baseline shaft position and vibration measurements after commissioning. Comparing subsequent measurements with the baseline can help maintenance personnel identify changes in machine behavior and investigate potential mechanical problems.

Conclusion

The Epro PR6424/107-000 16 mm Eddy Current Sensor is a non-contact measurement probe designed for shaft displacement and vibration monitoring in critical rotating machinery. Its eddy current operating principle allows it to measure the distance between the sensor tip and a conductive target without mechanical contact.

With typical PR6424 family specifications including 4 V/mm sensitivity, a ±2.0 mm static measurement range, and a 0–1,000 μm dynamic measurement range, the sensor can support machinery monitoring applications involving turbines, compressors, pumps, and industrial fans.

For procurement and replacement work, the complete model number and system configuration should be verified. Correct matching of the sensor, cable, signal converter, and monitoring equipment is essential for reliable measurement and effective machinery protection.