Product Overview

The EPRO PR6424/010-130 16 mm Eddy Current Sensor is a non-contact displacement measurement probe designed for monitoring the condition of critical rotating machinery. It belongs to the PR6424 sensor family originally developed for industrial machinery protection and monitoring applications and is associated with Emerson’s EPRO machinery health product range.

The sensor uses the eddy current measurement principle to detect changes in the distance between the probe tip and a conductive target. In rotating equipment, this allows the monitoring system to measure shaft vibration, radial and axial displacement, shaft position, eccentricity, and rotational reference information.

Unlike contact-based measurement devices, an eddy current sensor does not need to touch the rotating shaft. This is particularly important in turbines, compressors, pumps, and other machines operating at high speeds, where continuous physical contact would cause wear and could interfere with reliable measurement.

The PR6424 series features a 16 mm sensing head and is designed for critical turbomachinery applications. When connected to a compatible signal converter and machinery monitoring system, it provides measurement information that can be used to evaluate shaft movement and identify abnormal operating conditions.

The PR6424/010-130 is suitable for applications where non-contact shaft monitoring is required. Its specific configuration should be checked against the existing measurement chain, including the extension cable, connector, signal converter, and monitoring input.

Technical Specifications

Note: The technical performance figures above refer to published PR6424 family specifications. Confirm the exact /010-130 configuration, cable construction, connector, and temperature limits against the product documentation supplied with the individual unit.

Function and Working Principle

The PR6424/010-130 operates through electromagnetic induction. Its sensing element generates an alternating electromagnetic field near the probe tip. When a suitable conductive target, such as a ferromagnetic steel shaft, enters this field, eddy currents are induced in the target surface.

The induced currents affect the electrical characteristics of the probe. The resulting change in the measurement signal corresponds to the distance between the probe and the target.

When the probe is connected to a compatible signal converter, this information can be converted into a usable output for a machinery monitoring system.

1. Non-Contact Shaft Displacement Measurement

The primary function of the PR6424 sensor is to measure the relative distance between the probe and a rotating shaft.

The probe is mounted at a defined position near the shaft surface. As the shaft moves, the distance between the target and the probe changes. The sensor system detects these changes and provides information about shaft displacement.

This measurement method is useful for monitoring both static shaft position and dynamic shaft movement.

2. Shaft Vibration Monitoring

Rotating machinery can experience vibration due to imbalance, misalignment, bearing wear, looseness, shaft deformation, and other mechanical conditions.

An eddy current probe installed near the shaft can measure relative shaft vibration. The monitoring system evaluates the resulting signal to identify changes in vibration amplitude and operating behavior.

The PR6424 series has a published dynamic measurement range of 0–1,000 μm, making it suitable for applications requiring shaft vibration measurement within the specified operating limits.

3. Shaft Position Measurement

In addition to dynamic vibration, the sensor can measure the static distance between the probe and the shaft.

This information can be used to monitor shaft position and detect changes in the mechanical relationship between rotating and stationary components.

In turbine applications, shaft position measurements can contribute to the assessment of bearing condition and rotor movement.

4. Eccentricity Monitoring

Shaft eccentricity refers to the variation in the radial distance between the shaft surface and its rotational center.

By monitoring the shaft-to-probe distance during slow rotation or startup, the system can identify changes in shaft geometry or rotational behavior.

This measurement is relevant to large rotating machines, where rotor eccentricity can affect startup procedures and operating reliability.

5. Signal Conversion and Monitoring

The probe is part of a measurement system rather than a complete standalone monitoring instrument.

A compatible signal converter processes the probe signal and provides an output suitable for the machinery protection or monitoring equipment. The monitoring system then displays measurement values, evaluates alarm conditions, and may initiate protective actions according to the configured logic.

The converter must match the probe’s electrical characteristics and cable configuration. A probe and converter should not be mixed solely because they belong to the same general product family.

Role in Industrial Machinery Protection Systems

The PR6424/010-130 can be used as a measurement component in machinery protection systems where continuous monitoring of rotating shafts is important.

Turbine Monitoring

Steam and gas turbines operate under demanding mechanical and thermal conditions. Shaft displacement and vibration measurements provide information about rotor behavior during startup, steady operation, load changes, and shutdown.

The PR6424 series is designed for critical turbomachinery monitoring applications and can be used as part of a suitable turbine monitoring arrangement.

Compressor Protection

Industrial compressors often operate continuously and may be exposed to changing loads, pressure conditions, and operating speeds.

Shaft vibration and position measurements can help maintenance teams identify abnormal mechanical behavior. Monitoring trends over time can support condition-based maintenance and fault investigation.

Pump Monitoring

Large industrial pumps are used in power generation, petrochemical processing, water treatment, and other process industries.

An eddy current probe can monitor shaft movement in compatible pump arrangements. This information may help identify changes associated with bearing wear, shaft misalignment, or other mechanical problems.

Integration with Machinery Monitoring Systems

The PR6424 probe can be incorporated into a complete machinery monitoring chain that includes:

• Eddy current probe.
• Extension cable, where required.
• Compatible signal converter.
• Machinery monitoring module.
• Control or protection system.
• Operator monitoring interface.

The exact system arrangement depends on the converter type, cable configuration, monitoring hardware, and application requirements.

Industrial Applications

1. Steam Turbines

Steam turbines require continuous monitoring of rotor vibration and shaft position to support safe and stable operation.

The PR6424 sensor can be installed near suitable shaft measurement locations to provide displacement information to the machinery monitoring system.

Typical monitoring purposes include:

• Radial shaft vibration measurement.
• Axial shaft displacement monitoring.
• Rotor eccentricity assessment.
• Startup and shutdown condition monitoring.
• Mechanical condition trending.

2. Gas Turbines

Gas turbines operate at high rotational speeds and under demanding temperature and mechanical conditions.

Non-contact shaft monitoring provides useful information about rotor movement without requiring physical contact with the rotating shaft.

Probe selection must account for installation geometry, target material, cable routing, temperature exposure, and the requirements of the complete monitoring system.

3. Hydro Turbines

Hydro turbines are used in power generation facilities and may operate continuously for long periods.

Shaft displacement and vibration monitoring can help operators evaluate the condition of the rotating assembly, particularly when vibration patterns change with operating load or water-flow conditions.

4. Industrial Compressors

Centrifugal compressors and other large rotating compressors are important components in chemical plants, refineries, gas processing facilities, and industrial production systems.

The PR6424 sensor can provide shaft movement information for compatible compressor monitoring arrangements.

5. Industrial Pumps and Fans

Large pumps and fans are widely used in power plants, manufacturing facilities, and process industries.

Eddy current probes can be used in suitable installations to monitor shaft displacement and vibration. The measurements can help maintenance teams evaluate machine condition and identify developing mechanical problems.

Installation and System Integration

Correct installation is essential for obtaining stable and reliable measurements from an eddy current sensor.

1. Confirm the Measurement Target

The PR6424 series is designed to measure suitable conductive targets, with ferromagnetic steel identified as the standard target material.

The target material and surface condition influence measurement performance. If the shaft material differs from the standard reference material, verify whether calibration or an appropriate correction is required.

2. Select the Correct Mounting Position

The sensor must be installed at the intended measurement location with a suitable distance from the shaft.

The mounting position should provide adequate clearance and avoid interference with adjacent mechanical components. The probe must also be securely fixed to prevent movement during machine operation.

3. Set the Operating Air Gap

The published PR6424 family specification identifies a nominal center air gap of approximately 2.7 mm.

The actual installation gap should follow the applicable sensor and converter documentation. Incorrect positioning may result in an output outside the intended linear measurement region.

A suitable initial gap is important for both static position measurement and dynamic vibration measurement.

4. Check Cable and Connector Compatibility

Cable type and connector configuration are important parts of the measurement system.

Before installation, confirm:

• Probe cable length.
• Armored or unarmored cable construction.
• Connector type.
• Extension cable requirements.
• Compatible signal converter.
• Cable routing and shielding requirements.

The suffix /010-130 should be checked against the complete product documentation rather than interpreted from the model number alone.

5. Connect the Signal Converter

The probe should be connected to a compatible EPRO signal converter.

The converter processes the probe signal and provides the appropriate output for the monitoring system. Incorrect converter selection may cause measurement errors or prevent the sensor from operating correctly.

Verify the complete probe-converter combination before commissioning.

6. Verify Measurement Output

After installation, check the output signal under the required calibration conditions.

The commissioning process should include:

• Inspection of probe mounting.
• Verification of cable and connector condition.
• Confirmation of the initial air gap.
• Verification of the converter configuration.
• Measurement output checks.
• Comparison with the expected shaft position.
• Alarm and monitoring system verification.

The final settings should be documented for future maintenance and replacement work.

Compatible System Components

The PR6424/010-130 is normally used as part of a complete machinery measurement system. The following components may be relevant depending on the installation.

These components are examples of equipment used in EPRO machinery monitoring systems. They are not necessarily included with the PR6424/010-130 sensor.

Alternative Models and Replacement Considerations

The PR6424 series includes different probe configurations. Replacement selection should be based on the mechanical and electrical characteristics of the installed measurement system.

Before replacing the PR6424/010-130, compare:

• Sensor head diameter.
• Probe body dimensions and mounting thread.
• Cable length and construction.
• Connector type.
• Signal converter compatibility.
• Sensitivity and linear measurement range.
• Operating temperature.
• Target material.
• Installation air gap.
• Monitoring system input requirements.

A replacement probe with the same 16 mm head diameter may still have a different cable, connector, or electrical configuration. Always verify the complete measurement chain before installation.

Key Advantages

Non-Contact Measurement

The sensor measures shaft displacement without touching the rotating surface. This avoids the mechanical wear associated with contact-based measurement methods.

Suitable for Critical Rotating Machinery

The PR6424 family is designed for machinery such as steam turbines, gas turbines, compressors, pumps, and fans.

Shaft Vibration and Position Monitoring

The sensor can provide information about both dynamic shaft movement and static shaft position when used with a compatible converter.

High Measurement Sensitivity

The published PR6424 family sensitivity is 4 V/mm, with a specified linearity of ≤ ±1.5%.

Compact 16 mm Sensor Head

The 16 mm sensing head supports installation in suitable machinery monitoring locations where the available mounting space is limited.

Industrial Measurement Design

The stainless steel sleeve and PTFE cable construction are intended for industrial measurement applications within the specified operating conditions.

Integration with Machinery Monitoring Systems

The probe can be incorporated into a compatible EPRO measurement chain for continuous monitoring and machinery protection.

Technical FAQs

1. What is the EPRO PR6424/010-130?

The PR6424/010-130 is a 16 mm eddy current displacement sensor used 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 the eddy current principle. The probe generates an electromagnetic field, and changes in the distance to a conductive target affect the probe’s electrical response. A compatible signal converter processes this information into a measurement output.

4. What is the sensitivity of the PR6424 series?

The published sensitivity is 4 V/mm, equivalent to approximately 101.6 mV/mil, with a specified linearity of ≤ ±1.5%.

5. What is the static measurement range?

The published PR6424 family static measurement range is ±2.0 mm.

6. What is the dynamic measurement range?

The published dynamic measurement range is 0–1,000 μm.

7. What material can the sensor measure?

The standard target material identified in the PR6424 specifications is ferromagnetic steel, with 42CrMo4 used as the reference material.

8. Which industries use the PR6424 sensor?

Typical applications include power generation, petrochemical processing, oil and gas, industrial manufacturing, and other industries operating critical rotating machinery.

9. Does the sensor work independently?

No. It is normally used with a compatible signal converter and machinery monitoring equipment. The converter processes the probe signal for use by the monitoring system.

10. What is the weight of the PR6424/010-130?

The supplied listing weight is 0.2 kg. The published PR6424 specification gives approximately 200 g for the sensor with a 1 m cable and without armor. Actual weight depends on the cable and configuration.

Procurement and Maintenance Recommendations

When purchasing the EPRO PR6424/010-130, verify the complete model number and the configuration of the existing probe. The 16 mm sensor head alone is not sufficient to establish compatibility.

For replacement projects, check the probe mounting thread, overall dimensions, cable length, cable armor, connector, signal converter, and monitoring system input. These details are important because different PR6424 configurations may have similar sensing principles but different mechanical or electrical arrangements.

For used or refurbished sensors, inspect the probe body, sensing tip, cable insulation, connector, and mounting thread. Damaged cables or connectors can affect measurement stability and should be evaluated before installation.

During routine maintenance, inspect the probe mounting and cable routing. Check for loose fittings, damaged insulation, contamination, and changes in the measurement output. Compare current measurements with established operating trends to identify unusual changes.

For critical turbine and compressor applications, sensor replacement should follow the machinery protection system’s maintenance procedures. Calibration and commissioning should be performed using the appropriate documentation and compatible test equipment.

Conclusion

The EPRO PR6424/010-130 16 mm Eddy Current Sensor is designed for non-contact shaft displacement and vibration measurement in critical rotating machinery. Its PR6424 family specifications include 4 V/mm sensitivity, a ±2.0 mm static measurement range, and a 0–1,000 μm dynamic measurement range.

The sensor can be used in suitable turbine, compressor, pump, and fan monitoring systems when paired with a compatible signal converter and monitoring module. For procurement and replacement, verifying the complete probe configuration, cable arrangement, connector, and converter compatibility is essential to maintaining reliable machinery monitoring.