Product Overview

The EPRO PR6424/013-000 16 mm Eddy Current Sensor is a non-contact displacement and vibration measurement probe designed for monitoring the operating condition 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, now part of Emerson, the PR6424 series is commonly used in steam turbines, gas turbines, compressors, pumps, fans, and other large rotating machines. The sensor measures changes in the distance between its probe tip and a conductive metallic target, allowing monitoring systems to evaluate shaft displacement, vibration, axial position, eccentricity, and related mechanical conditions.

Unlike contact-based measurement devices, an eddy current sensor does not need to physically touch the rotating shaft. This non-contact measurement principle reduces mechanical wear at the sensing point and supports continuous monitoring while machinery is operating.

The PR6424/013-000 is identified as a 16 mm sensor-head model. Its supplied listing specifications include a sensor head diameter of 16 mm and a weight of approximately 0.2 kg. The exact cable length, connector arrangement, mounting configuration, and converter compatibility should be checked against the complete product identification and original configuration.

For industrial users, the sensor is particularly relevant to machinery condition-monitoring systems where reliable shaft displacement and vibration measurements are important for equipment protection, maintenance planning, and operational analysis.

Technical Specifications

Note: The table combines the supplied listing data with published PR6424 family specifications. Exact cable, connector, temperature, and compatibility details should be confirmed for the PR6424/013-000 variant before installation.

Function and Working Principle

The PR6424/013-000 operates using the eddy current measurement principle. It generates an electromagnetic field near the probe tip and detects changes in that field when a conductive metallic target moves relative to the sensor.

This method enables the monitoring system to measure the distance between the probe and a rotating shaft without physical contact.

1. Eddy Current Measurement Principle

An oscillator inside the compatible measurement system generates a high-frequency electrical signal in the sensor coil. This signal produces an electromagnetic field around the probe tip.

When a conductive target, such as a ferromagnetic steel shaft, enters the field, eddy currents are induced in the target surface. These currents affect the electrical characteristics of the sensor coil.

The resulting change in the sensor’s electrical response is related to the distance between the probe and the target. A compatible signal converter processes this response and produces a measurement signal for the machinery monitoring system.

2. Shaft Displacement Measurement

Shaft displacement monitoring is important for understanding the mechanical condition of rotating equipment.

The PR6424 series provides a static measurement range of approximately ±2.0 mm under its specified measurement conditions. This allows a monitoring system to observe changes in shaft position relative to the installed probe.

Such measurements can help identify abnormal shaft movement, changes in bearing clearances, or shifts in mechanical alignment.

3. Shaft Vibration Measurement

Rotating machinery naturally produces some vibration during operation. However, excessive or changing vibration may indicate mechanical problems.

The PR6424 sensor detects dynamic movement of the shaft surface. When connected to a compatible converter and monitoring system, the resulting signal can be used to evaluate shaft vibration.

The published PR6424 family dynamic measurement range is 0–1,000 μm. The actual usable range depends on the sensor configuration, target material, installation gap, and measurement-system settings.

4. Axial Position and Eccentricity Monitoring

The sensor can also be applied to monitor axial shaft movement and eccentricity when installed in an appropriate measurement arrangement.

Axial position monitoring helps operators identify changes in the shaft’s position along its rotational axis. Eccentricity measurement can provide information about the geometric relationship between the shaft and its rotational center.

These measurements are useful in turbine and compressor protection systems where changes in shaft position can be associated with mechanical wear, thermal expansion, or abnormal operating conditions.

5. Signal Conversion

The sensor probe is part of a measurement chain rather than a standalone controller. Its electrical response must be processed by a compatible signal converter.

The converter conditions the probe signal and provides an output suitable for the associated machinery monitoring system. Correct matching between the probe, extension cable, and converter is essential for accurate measurements.

Role in Industrial Machinery Monitoring Systems

The PR6424/013-000 is designed to provide measurement information to machinery protection and condition-monitoring systems.

In a typical installation, the sensor is mounted near the shaft of a rotating machine. Its output is connected through the appropriate cable arrangement to a compatible converter, which supplies a processed signal to the monitoring equipment.

Turbine Monitoring

Steam and gas turbines contain high-speed rotating components that require continuous monitoring. Shaft displacement and vibration measurements help operators assess the mechanical condition of the rotor and associated bearing systems.

The PR6424 series is designed for applications involving large shafts, including machinery with shaft diameters of at least 80 mm under the specified measurement conditions.

Compressor Monitoring

Industrial compressors operate under changing pressure, temperature, and load conditions. Shaft vibration and displacement measurements can provide useful information about rotor behavior and mechanical stability.

The sensor can be installed at selected monitoring points to provide measurement signals for the compressor protection system.

Pump Monitoring

Large industrial pumps may experience changes in vibration due to bearing wear, imbalance, misalignment, or hydraulic operating conditions.

A non-contact shaft measurement system can help monitor shaft movement without introducing mechanical contact between the sensor and the rotating component.

PLC and Machinery Protection Integration

The sensor itself does not function as a PLC input module. Its measurement signal is normally processed by a compatible converter or machinery monitoring system before being made available to higher-level control and supervisory equipment.

Depending on the system architecture, measurement information can be used by monitoring equipment, protection relays, PLCs, or plant supervisory systems.

The exact interface depends on the converter and monitoring hardware selected for the installation.

Industrial Applications

The EPRO PR6424/013-000 is intended for applications where non-contact measurement of rotating machinery is required.

1. Steam Turbines

Steam turbines operate under demanding mechanical and thermal conditions. Continuous shaft monitoring is important for identifying changes in rotor movement and detecting abnormal vibration.

The PR6424 sensor can be installed as part of a shaft displacement and vibration measurement arrangement. Its measurements can help support turbine condition monitoring and machinery protection.

2. Gas Turbines

Gas turbines are used in power generation and industrial drive applications. Their rotating components require accurate monitoring to support stable operation.

Non-contact eddy current sensors can provide shaft movement information for monitoring systems that evaluate vibration and rotor position.

3. Industrial Compressors

Centrifugal and other large industrial compressors operate with high-speed rotating shafts. Changes in vibration or displacement may indicate mechanical problems requiring inspection.

The PR6424 series can be used in compatible compressor monitoring arrangements to provide continuous measurement information.

4. Industrial Pumps

Large process pumps are widely used in chemical plants, power stations, refineries, and water-treatment facilities.

Shaft vibration and position monitoring can help maintenance teams evaluate pump condition and identify developing mechanical problems.

5. Fans and Blowers

Large industrial fans and blowers are used in ventilation, combustion-air supply, cooling, and material-handling systems.

The sensor can support shaft monitoring where non-contact displacement measurement is required and the installation meets the sensor’s measurement conditions.

6. Power Generation Equipment

Power generation facilities depend on reliable rotating machinery. Continuous monitoring of shaft movement and vibration can help operators assess equipment condition and plan maintenance activities.

The PR6424 series is designed for use in critical turbomachinery applications where measurement reliability is important.

Installation and System Integration

Correct installation is essential for achieving reliable measurements from an eddy current sensor.

1. Sensor Mounting

The sensor must be mounted securely near the measurement target. The mounting arrangement should prevent unwanted movement, vibration, or changes in probe position.

The PR6424 series uses a threaded sensor body. The exact thread and mounting dimensions should be checked against the technical drawing for the specific variant.

The probe should be positioned so that its sensing tip faces the intended metallic target surface.

2. Initial Air Gap Adjustment

The distance between the sensor tip and the target surface is an important installation parameter.

The published PR6424 family nominal center air gap is approximately 2.7 mm. The correct initial gap should be established using the manufacturer’s installation procedure and the specifications of the complete measurement chain.

Incorrect gap adjustment may cause measurement errors, reduced linear range, or unstable signals.

3. Target Material Selection

Eddy current measurements depend on the electrical and magnetic properties of the target material.

The PR6424 family specifications identify ferromagnetic steel, with 42CrMo4 as the standard target material. If the actual shaft material differs, the measurement characteristics may change.

The target material should therefore be checked before commissioning.

4. Cable Routing

The sensor cable should be routed carefully to avoid excessive bending, mechanical damage, and interference from nearby power conductors.

The PR6424 family uses PTFE-insulated cable. Cable length, connector type, and extension-cable compatibility should be confirmed for the exact sensor configuration.

Where required, use the approved extension cable and connector arrangement specified for the measurement chain.

5. Signal Converter Compatibility

The PR6424 probe must be paired with a compatible signal converter.

Converter selection should consider the sensor model, cable arrangement, measurement range, output configuration, and monitoring-system requirements.

Do not assume that every PR6424 probe variant can be connected to every converter without checking the manufacturer’s compatibility information.

6. Commissioning and Signal Verification

After installation, verify the mechanical mounting, initial air gap, cable connections, converter configuration, and measurement output.

The monitoring system should be checked against the expected measurement range. Abnormal signal behavior may result from incorrect probe positioning, cable damage, incompatible conversion hardware, or an unsuitable target surface.

Document the final installation settings to support future maintenance and replacement.

Compatible System Components

A complete PR6424 measurement arrangement generally includes the sensor, suitable cable components, and a compatible signal converter.

The components listed are examples of equipment used in EPRO measurement systems. They are not automatically included with the PR6424/013-000 sensor.

Alternative Models and Replacement Considerations

The PR6424 family includes multiple probe configurations. These models may share a 16 mm sensing tip but can differ in cable length, connector arrangement, sensor-body length, and compatibility details.

Before replacing the PR6424/013-000, compare the complete part number, sensor length, thread type, cable length, connector, operating-temperature requirements, and converter compatibility.

A sensor with the same 16 mm tip diameter is not necessarily a direct replacement. Mechanical fit and measurement-chain compatibility must both be verified.

Key Advantages

Non-Contact Measurement

The eddy current principle allows the sensor to measure shaft movement without physical contact. This avoids mechanical contact wear at the sensing point.

Designed for Critical Rotating Machinery

The PR6424 family is intended for applications involving turbines, compressors, pumps, and fans, where shaft displacement and vibration measurements are important.

High Measurement Sensitivity

The published family sensitivity of 4 V/mm supports the measurement of small changes in probe-to-target distance when used with the appropriate converter.

Static and Dynamic Measurement

The PR6424 family supports both static shaft-position measurement and dynamic vibration measurement within its specified operating range.

Industrial Temperature Capability

The sensor family is designed for demanding industrial environments. The permissible operating temperature depends on the exact sensor configuration and should be confirmed before installation.

Integration with Machinery Monitoring Systems

When paired with compatible conversion and monitoring equipment, the sensor can provide measurement information for machinery condition monitoring and protection.

Compact 16 mm Sensor Head

The 16 mm sensing head supports installation in suitable machinery monitoring locations where a compact probe is required.

Technical FAQs

1. What is the EPRO PR6424/013-000?

The PR6424/013-000 is a 16 mm eddy current sensor used for non-contact measurement of shaft displacement and vibration in rotating machinery.

2. What is the sensor head diameter?

The sensor head diameter is 16 mm, consistent with the PR6424 product family.

3. What is the measuring principle?

It uses the eddy current principle. The sensor generates an electromagnetic field, and changes in the electrical response caused by a nearby conductive target are used to determine the distance between the probe and the target.

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

The published family specification provides a static measurement range of approximately ±2.0 mm and a dynamic measurement range of 0–1,000 μm. Actual performance depends on the measurement-chain configuration and installation conditions.

5. What is the sensitivity?

The typical PR6424 family sensitivity is 4 V/mm, with a published linearity of no more than ±1.5%.

6. What type of shaft material is suitable?

The standard target material is ferromagnetic steel, with 42CrMo4 identified in the family specifications. Other materials should be evaluated against the manufacturer’s measurement requirements.

7. Which machines can use this sensor?

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

8. Does the sensor require a signal converter?

Yes. The sensor is part of an eddy current measurement chain and requires compatible signal-conversion equipment to process its measurement response.

9. Can the PR6424/013-000 be connected directly to a PLC?

It should not be treated as a standard direct PLC input device. A compatible converter or machinery monitoring system is normally required to condition the signal before it is used by a PLC or supervisory system.

10. What should be checked before replacing the sensor?

Check the complete model number, sensor diameter, probe length, thread, cable length, connector, initial air gap, target material, and converter compatibility. Matching only the 16 mm diameter is not sufficient.

Procurement and Maintenance Recommendations

When purchasing the EPRO PR6424/013-000, verify the complete model identification and the physical configuration of the sensor. Particular attention should be given to the cable arrangement, connector type, probe-body dimensions, and compatibility with the installed signal converter.

For replacement projects, compare the original sensor with the proposed replacement using the machinery manufacturer’s documentation. Even small differences in probe length or cable configuration can affect installation and measurement-chain compatibility.

During maintenance, inspect the probe body, cable insulation, connector, and mounting threads. Look for signs of mechanical damage, corrosion, loose connections, or cable deterioration. Confirm the initial air gap and review the measurement signal if abnormal readings are observed.

It is also useful to keep a record of the installed probe model, converter model, cable arrangement, and commissioning settings. This information can reduce troubleshooting time and simplify future spare-parts procurement.

Conclusion

The EPRO PR6424/013-000 16 mm Eddy Current Sensor is designed for non-contact measurement of shaft displacement and vibration in critical rotating machinery. Its 16 mm sensing head and the PR6424 family’s published measurement characteristics make it suitable for integration into compatible turbine, compressor, pump, and fan monitoring systems.

With a typical sensitivity of 4 V/mm and a static measurement range of ±2.0 mm, the PR6424 family supports both shaft-position and dynamic vibration monitoring. For reliable operation, the sensor must be installed with the correct air gap and connected to a compatible cable, converter, and machinery monitoring system.

Accurate model verification is essential when purchasing or replacing the PR6424/013-000, particularly because different probe variants may have different mechanical and electrical configurations.