Product Overview

The Epro PR6424/015-100 16 mm Eddy Current Sensor is a non-contact displacement measurement probe designed for monitoring the condition and operating behavior of critical rotating machinery. It belongs to the PR6424 sensor family developed for industrial machinery protection and condition-monitoring applications.

Manufactured under the EPRO product line associated with Emerson, the PR6424 series is used to measure shaft vibration, radial and axial displacement, shaft position, eccentricity, and rotational reference information. Its non-contact measurement principle allows the sensor to monitor the distance between the probe tip and a conductive target without physically touching the rotating shaft.

The PR6424/015-100 has a nominal sensor head diameter of 16 mm and is designed for applications involving larger rotating shafts. It is commonly considered for machinery such as steam turbines, gas turbines, hydro turbines, compressors, pumps, and industrial fans.

Unlike a conventional contact sensor, an eddy current probe measures changes in the electromagnetic interaction between its sensing coil and a conductive target. The resulting measurement signal can be processed by a compatible signal converter and supplied to a machinery monitoring or protection system.

The PR6424/015-100 is relevant to industrial facilities where continuous monitoring of shaft movement is important for equipment reliability. Abnormal shaft displacement or vibration may indicate mechanical imbalance, misalignment, bearing deterioration, rotor instability, or other developing problems.

When selecting this sensor for maintenance or replacement, the complete model number should be checked. Probe dimensions, cable configuration, connector type, converter compatibility, and calibration requirements must match the existing measurement system.

Technical Specifications

Note: The measurement specifications above describe the PR6424 family. Confirm the exact /015-100 cable and connector configuration against the product label and applicable technical documentation.

Function and Working Principle

The PR6424/015-100 operates using the eddy current measurement principle. It generates an electromagnetic field near the sensor tip and detects changes in that field when a conductive target approaches or moves away from the probe.

This method provides a measurement of the distance between the probe and the target without requiring physical contact.

1. Electromagnetic Field Generation

An electrical signal supplied through a compatible signal converter energizes the sensing coil inside the probe. The coil generates a high-frequency electromagnetic field around the sensor tip.

When the probe is installed near a conductive metal shaft, this field interacts with the target surface.

2. Eddy Current Formation

The electromagnetic field induces small circulating electrical currents, known as eddy currents, in the conductive target.

The strength of these currents depends on the distance between the sensor and the target, as well as the target’s electrical and magnetic properties.

As the shaft moves relative to the probe, the electromagnetic interaction changes. The sensor system detects these variations and uses them to determine the distance between the probe and the shaft.

3. Displacement Measurement

The PR6424 series provides a static measurement range of approximately ±2.0 mm and a dynamic measurement range of 0–1,000 μm peak-to-peak under its specified operating conditions.

Static measurements can be used to monitor shaft position and slow changes in clearance. Dynamic measurements help identify vibration and repetitive shaft movement during machine operation.

These measurements are useful for identifying changes in rotor behavior and evaluating machinery condition.

4. Signal Conversion

The probe is normally used as part of a complete measurement chain that includes an extension cable, where required, and a compatible signal converter.

The converter processes the probe’s electrical characteristics and produces a conditioned output suitable for monitoring equipment.

A complete system must use compatible probe, cable, and converter components. Mixing components with different electrical characteristics or calibration settings can cause measurement errors.

5. Machinery Condition Monitoring

The sensor provides information about shaft movement that can be evaluated by machinery protection equipment or a condition-monitoring system.

When vibration or displacement exceeds configured operating limits, the monitoring system may generate an alarm or initiate a protection response, depending on the plant’s control and safety design.

Role in Industrial Machinery Protection Systems

The PR6424/015-100 is a sensing component within a broader machinery monitoring arrangement. It provides measurement information that helps engineers assess the mechanical condition of rotating equipment.

Shaft Vibration Monitoring

Rotating shafts may develop vibration due to imbalance, misalignment, looseness, bearing problems, or changes in operating conditions.

A correctly installed eddy current probe measures shaft movement relative to its mounting point. The resulting signal can help maintenance teams identify abnormal vibration patterns and investigate developing mechanical faults.

Axial Displacement Monitoring

Axial shaft movement can be important in turbines, compressors, and other large rotating machines.

The sensor can be installed in an appropriate orientation to monitor axial displacement. Changes in shaft position may indicate thrust-bearing problems, thermal expansion effects, or changes in rotor operating conditions.

Shaft Position and Eccentricity Measurement

The PR6424 series can also be used to monitor shaft position and eccentricity.

These measurements help engineers evaluate rotor alignment and mechanical movement. Monitoring changes over time can support maintenance decisions and equipment troubleshooting.

Integration with Monitoring Systems

A typical installation connects the probe to a compatible signal converter and then to machinery monitoring equipment.

The monitoring system may provide:

• Continuous vibration measurement.
• Shaft displacement monitoring.
• Position and eccentricity information.
• Alarm and trip functions.
• Historical measurement trends.
• Machinery condition analysis.

The exact monitoring functions depend on the selected converter, monitoring hardware, and plant configuration.

Industrial Applications

The Epro PR6424/015-100 is designed for industrial applications where non-contact shaft measurement is required.

1. Steam Turbines

Steam turbines operate at high rotational speeds and require continuous monitoring of rotor movement.

The PR6424 series can be used to measure shaft vibration and displacement at suitable monitoring locations. These measurements help maintenance personnel evaluate rotor behavior and identify abnormal mechanical conditions.

2. Gas Turbines

Gas turbines are critical assets in power generation and industrial energy systems. Rotor vibration and displacement measurements are important for monitoring mechanical stability.

An appropriately configured PR6424 measurement chain can provide shaft movement information for the turbine’s machinery protection system.

3. Hydro Turbines

Hydro turbines operate under changing hydraulic and mechanical conditions. Shaft vibration and position measurements help operators evaluate rotating assembly behavior.

The sensor can be used at suitable measurement points where the target material, shaft diameter, installation geometry, and measurement requirements meet the probe specifications.

4. Industrial Compressors

Centrifugal and other large compressors often operate continuously in demanding process environments.

Shaft vibration and displacement monitoring can help identify mechanical changes before they develop into serious equipment problems. The PR6424 series is suitable for consideration in compressor monitoring systems when the measurement configuration is correctly matched.

5. Pumps and Fans

Large industrial pumps and fans may experience vibration caused by imbalance, alignment problems, bearing deterioration, or changing process loads.

Non-contact shaft monitoring provides additional information for condition-based maintenance and troubleshooting.

6. Power Generation Equipment

Power plants use turbines, generators, pumps, and auxiliary rotating equipment that require reliable monitoring.

The PR6424/015-100 can form part of a machinery monitoring arrangement designed to track shaft movement and support equipment reliability programs.

Installation and System Integration

Correct installation is essential for accurate measurement and dependable operation.

1. Verify the Probe Configuration

Before installation, check the complete model number and confirm that the replacement probe matches the existing system.

Important details include:

• Sensor head diameter.
• Thread size and mounting arrangement.
• Probe length.
• Cable construction and length.
• Connector type.
• Signal converter compatibility.
• Calibration characteristics.

The /015-100 suffix should not be treated as interchangeable with other PR6424 variants without checking the detailed configuration.

2. Select the Correct Mounting Position

The probe should be installed at the measurement location specified by the machinery manufacturer or monitoring-system design.

The sensor tip must face the intended conductive target and maintain the required clearance throughout machine operation.

The PR6424 series is designed for a nominal center air gap of approximately 2.7 mm under its specified standard configuration. The final installation gap should follow the relevant probe and converter calibration instructions.

3. Check the Target Surface

The target material affects eddy current sensor performance.

The PR6424 series is specified for ferromagnetic steel targets, with 42CrMo4 used as the standard reference material in the published specifications.

Target material, surface condition, shaft diameter, and measurement geometry should be considered during installation. A different target material may affect sensitivity and calibration.

4. Connect the Cable and Signal Converter

The probe must be connected to a compatible signal converter using the specified cable and connector arrangement.

Check the cable for damage, sharp bends, excessive mechanical tension, and exposure to temperatures beyond its permitted range.

Cable routing should avoid unnecessary proximity to high-power conductors and sources of electromagnetic interference where possible.

5. Configure the Monitoring System

After the probe is installed, verify the measurement chain and configure the monitoring system according to the machinery and instrumentation requirements.

Check the initial air gap, signal output, measurement scaling, alarm thresholds, and channel configuration.

Where the probe is part of a machinery protection system, all alarm and trip settings should be validated under the approved commissioning procedure.

6. Perform Functional Testing

Before returning the machinery to normal operation, verify that the probe signal is stable and responds correctly to changes in target position.

Check the complete signal path from the sensor through the converter to the monitoring equipment. Confirm that the displayed values and configured alarm limits correspond to the intended engineering units.

Compatible System Components

The PR6424/015-100 is normally used as part of a complete eddy current measurement chain. The following components may form part of a suitable installation, subject to exact model compatibility.

The table describes typical system components rather than a guaranteed package. The probe, cable, converter, and monitoring hardware must be checked together before ordering.

Alternative Models and Replacement Considerations

The PR6424 family includes different probe configurations designed for specific installation and cable requirements. A replacement should be selected according to the complete model number and measurement-system compatibility.

These are related product-family examples, not guaranteed direct substitutes for the PR6424/015-100.

Before replacing an installed probe, compare:

• Complete model and suffix.
• Sensor head diameter.
• Thread and mounting dimensions.
• Probe length.
• Cable length and construction.
• Connector and extension-cable arrangement.
• Sensitivity and measurement range.
• Signal converter model.
• Calibration and target material.
• Monitoring-system input requirements.

A sensor with the same 16 mm head diameter may still have a different cable or electrical configuration. Always verify the complete measurement chain.

Key Advantages

Non-Contact Measurement

The eddy current principle allows the probe to measure shaft movement without physical contact. This is suitable for high-speed rotating equipment where contact measurement is impractical.

Shaft Vibration Monitoring

The PR6424 series supports dynamic displacement measurement, providing information that can help engineers evaluate rotating machinery vibration.

Position Measurement

The sensor can also be used for static shaft position and displacement monitoring within its specified measuring range.

High Measurement Sensitivity

The published PR6424 family sensitivity is 4 V/mm, with linearity of up to ±1.5% under the specified conditions.

Industrial Machinery Applications

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

Integration with Machinery Monitoring Systems

When paired with compatible signal-conditioning and monitoring equipment, the probe can contribute to continuous machinery condition monitoring and protection.

Compact 16 mm Sensor Head

The 16 mm sensing head supports installation in appropriately designed machinery measurement locations.

Technical FAQs

1. What is the Epro PR6424/015-100?

The Epro PR6424/015-100 is a 16 mm eddy current displacement sensor designed for non-contact measurement of shaft vibration, displacement, position, and related rotating-machinery parameters.

2. What is the sensor head diameter?

The nominal sensor head diameter is 16 mm.

3. What measurement principle does it use?

It uses the eddy current principle. An electromagnetic field interacts with a conductive target, and changes in the interaction are used to determine the distance between the probe and the target.

4. What is the measurement range?

The PR6424 family has a static measurement range of approximately ±2.0 mm and a dynamic range of 0–1,000 μm peak-to-peak under the specified operating conditions.

5. What is its sensitivity?

The published PR6424 family sensitivity is 4 V/mm, with linearity up to ±1.5%.

6. Which materials can it measure?

The standard PR6424 calibration is based on ferromagnetic steel, with 42CrMo4 used as the reference target material. Different materials may affect measurement performance and should be evaluated during system configuration.

7. Does the sensor work independently?

It is normally used with a compatible extension cable and signal converter. The converter processes the probe signal for use by machinery monitoring equipment.

8. Where is the PR6424/015-100 commonly used?

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

9. What should be checked before purchasing a replacement?

Verify the complete model number, probe diameter, mounting thread, cable configuration, connector type, converter compatibility, and calibration requirements.

10. What is the weight of the sensor?

The supplied product weight is approximately 0.2 kg. Published PR6424 family documentation also gives a reference weight of approximately 200 grams for the sensor with a 1-meter cable and without armor.

Procurement and Maintenance Recommendations

When purchasing the Epro PR6424/015-100, confirm the complete product designation and compare it with the installed probe. The suffix is important because different variants may use different cable lengths, connectors, mounting arrangements, or electrical configurations.

For industrial spare-parts procurement, request clear photographs of the sensor label, probe head, threaded section, cable, and connector. Confirm whether the product is supplied as a sensor-only assembly or includes additional cable and connection accessories.

During maintenance, inspect the sensor tip, threaded mounting section, cable insulation, and connector for visible damage. Check that the probe remains securely installed and that its measurement gap has not changed.

If a sensor is replaced, verify the complete measurement chain. A replacement probe should be matched with the appropriate cable and converter, and the monitoring channel should be checked for correct scaling and calibration.

For critical rotating machinery, follow the plant’s approved machinery protection and maintenance procedures. Do not change alarm or trip settings without the required engineering review and authorization.

Conclusion

The Epro PR6424/015-100 16 mm Eddy Current Sensor is designed for non-contact shaft displacement and vibration measurement in critical industrial rotating machinery. Its 16 mm sensing head and PR6424 family measurement characteristics make it suitable for applications involving turbines, compressors, pumps, fans, and other large rotating equipment.

With a typical static measurement range of ±2.0 mm, sensitivity of 4 V/mm, and linearity of up to ±1.5%, the PR6424 family provides measurement information for machinery condition monitoring and protection systems.

For replacement and maintenance projects, confirming the exact probe variant, cable configuration, signal converter, and calibration requirements is essential to maintaining reliable measurement performance.