Product Overview

The EPRO PR6424/013-101 16mm Eddy Current Sensor is a non-contact displacement measurement probe designed for monitoring the operating condition of critical rotating machinery. Manufactured under the EPRO product line associated with Emerson, the PR6424 series is widely used in machinery protection and condition monitoring systems.

The sensor uses eddy current technology to measure the distance between its sensing tip and a conductive target, typically a ferromagnetic steel shaft. By detecting changes in this distance, the monitoring system can obtain information about shaft displacement, vibration, axial position, eccentricity, and rotational behavior.

Unlike contact-based measurement devices, an eddy current sensor does not need to touch the rotating shaft. This allows it to monitor shaft movement continuously without introducing mechanical contact between the probe and the monitored surface.

The PR6424 series has a nominal sensor head diameter of 16 mm and is designed for applications involving large rotating shafts. Typical installations include steam turbines, gas turbines, hydro turbines, compressors, pumps, fans, and industrial generators.

The PR6424/013-101 belongs to this 16 mm sensor family. Its supplied listing weight is 0.2 kg, while the published family specification gives an approximate weight of 200 grams for the sensor and a 1-meter cable without armor.

For a complete measurement system, the probe must be matched with the appropriate extension cable and signal converter. The exact cable length, connector arrangement, thread configuration, and converter compatibility should be confirmed against the full product code before ordering.

Technical Specifications

Note: The technical values above are PR6424 family specifications. Exact configuration details for the /013-101 variant, including cable length, armor, connector, thread, and calibration pairing, should be checked against the product label and manufacturer documentation.

Function and Working Principle

The PR6424/013-101 operates using the eddy current measurement principle. It generates an electromagnetic field at the sensor tip and detects changes caused by the presence and movement of a conductive target.

This allows the sensor to measure shaft displacement without physical contact.

1. Eddy Current Measurement

An alternating electrical signal energizes the sensor coil and creates an electromagnetic field around the probe tip.

When a conductive metal target approaches the sensing area, eddy currents are induced in the target surface. These currents affect the electromagnetic characteristics of the sensor coil.

The resulting electrical change is related to the distance between the sensor and the target. A compatible signal converter processes this information and generates an output suitable for a monitoring or machinery protection system.

2. Shaft Displacement Measurement

In rotating machinery, a shaft may move slightly because of bearing clearance, mechanical loading, thermal expansion, imbalance, or other operating conditions.

The PR6424 sensor measures the gap between its tip and the shaft surface. Changes in this gap can be used to determine shaft displacement relative to the probe mounting position.

The PR6424 family provides a static measurement range of approximately ±2.0 mm, making it suitable for monitoring shaft position within its specified operating range.

3. Shaft Vibration Monitoring

When a rotating shaft vibrates, its distance from the stationary probe changes continuously.

The sensor detects these variations and provides a signal that can be processed to determine vibration amplitude and other dynamic characteristics.

The PR6424 series has a dynamic measurement range of 0–1,000 μm peak-to-peak. This capability supports vibration monitoring in large rotating machinery where shaft movement is an important condition indicator.

4. Position and Eccentricity Monitoring

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

Eccentricity refers to a deviation between the geometric center of a shaft and its actual rotational behavior. Excessive eccentricity may indicate mechanical problems, uneven thermal expansion, or rotor-related abnormalities.

By continuously measuring the shaft-to-probe gap, a compatible monitoring system can identify changes that may require inspection.

5. Signal Conversion

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

A typical measurement chain includes:

• PR6424 eddy current sensor.
• Compatible extension cable, where required.
• Matching signal converter.
• Machinery monitoring or protection system.

The converter processes the sensor signal and provides a usable output for monitoring equipment. Sensor, cable, and converter compatibility is essential for accurate measurement.

Role in Industrial Machinery Protection Systems

The PR6424/013-101 can be used as a sensing component in industrial machinery condition monitoring systems. Its measurements help operators and maintenance engineers understand the mechanical behavior of rotating equipment.

Turbine Shaft Monitoring

Steam and gas turbines operate at high speeds and under demanding thermal and mechanical conditions. Shaft vibration and displacement are important parameters for evaluating rotor behavior.

A properly installed PR6424 sensor can measure shaft movement and provide information to the machinery monitoring system.

Compressor Monitoring

Industrial compressors contain rotating components that require continuous condition monitoring.

Shaft displacement and vibration measurements can help identify abnormal mechanical behavior, including changes associated with imbalance, bearing wear, or alignment problems.

Pump Condition Monitoring

Large industrial pumps may operate continuously in water treatment, chemical processing, power generation, and other process industries.

Non-contact shaft measurement can support monitoring of pump rotor behavior and help maintenance teams identify changes in operating conditions.

Generator Monitoring

Generators contain rotating shafts and bearings whose mechanical condition affects equipment reliability.

The PR6424 series can be applied in suitable generator monitoring arrangements to measure shaft movement and provide data for machinery protection systems.

Fan and Blower Monitoring

Large industrial fans and blowers may experience imbalance, shaft movement, and bearing-related vibration.

A non-contact displacement sensor can provide shaft vibration information without directly contacting the rotating component.

Industrial Applications

1. Steam Turbines

Steam turbines are used in power plants and industrial energy systems. Their rotors operate under high-speed conditions and may experience thermal expansion, mechanical loading, and vibration.

The PR6424 series can monitor shaft displacement and dynamic movement, providing information for machinery protection and maintenance decisions.

2. Gas Turbines

Gas turbines require reliable monitoring because rotor movement and vibration can affect mechanical performance.

A suitable eddy current sensor installation can provide continuous measurements of shaft behavior and help identify abnormal operating trends.

3. Hydro Turbines

Hydroelectric generating equipment often includes large rotating shafts and bearing assemblies.

The PR6424 sensor can be used in compatible monitoring systems to measure shaft displacement and vibration in hydro turbine installations.

4. Industrial Compressors

Centrifugal and other large compressors require accurate shaft monitoring to support stable operation.

The sensor can measure changes in shaft position and vibration, helping maintenance personnel evaluate the condition of rotating components.

5. Industrial Pumps

Large pumps used in chemical plants, power stations, and water treatment facilities may require continuous shaft condition monitoring.

The sensor provides non-contact displacement information that can be used by compatible monitoring equipment.

6. Industrial Fans and Blowers

Fans and blowers used in ventilation, combustion, and process systems may experience mechanical vibration during operation.

Shaft displacement measurements can contribute to condition monitoring and maintenance planning.

Installation and System Integration

Correct installation is essential for reliable measurement. Sensor mounting, target material, cable routing, and signal converter compatibility all influence measurement performance.

1. Verify the Sensor Configuration

Before installation, confirm that the complete sensor model is PR6424/013-101.

Check the sensor label and supplied documentation for:

• Thread size and mounting arrangement.
• Probe body length.
• Cable length.
• Armored or non-armored cable construction.
• Connector type.
• Compatible signal converter.
• Calibration and target material requirements.

Different PR6424 variants may have similar sensor head diameters but different mechanical and electrical configurations.

2. Prepare the Mounting Position

Install the sensor in a suitable mounting location near the monitored shaft.

The sensor must be securely fixed so that its position remains stable during machinery operation. Loose mounting can introduce measurement errors or unwanted movement.

The mounting arrangement should also allow sufficient clearance around the probe tip and prevent contact with the rotating shaft.

3. Set the Initial Air Gap

The distance between the sensor tip and the target shaft must be established according to the applicable calibration and installation instructions.

The PR6424 series has a nominal center air gap of approximately 2.7 mm. This value is a family-level reference and should not replace the specific installation procedure for the sensor and converter combination.

Incorrect air-gap adjustment may cause inaccurate readings or prevent the measurement chain from operating within its linear range.

4. Verify Target Material

The standard PR6424 calibration reference material is ferromagnetic steel, typically 42CrMo4.

The target material affects the electrical response of an eddy current sensor. If the actual shaft material differs from the standard reference, measurement accuracy may be affected unless the system is appropriately calibrated.

Confirm the shaft material and calibration requirements before commissioning.

5. Connect the Cable and Converter

Connect the sensor to the correct extension cable and signal converter.

Cable length, connector type, shielding, and electrical compatibility must be checked. Incorrect cable arrangements can affect signal quality and measurement accuracy.

The exact connector and cable configuration for PR6424/013-101 should be verified from its product documentation.

6. Configure the Monitoring System

After the probe and converter are installed, configure the monitoring system according to the measurement requirements.

Typical setup activities include:

• Confirming the sensor-converter combination.
• Establishing the correct measurement range.
• Checking the output scaling.
• Verifying the initial air gap.
• Confirming the target material.
• Testing static displacement readings.
• Checking dynamic vibration signals.

Record the commissioning values for future maintenance and troubleshooting.

7. Perform Functional Testing

Before returning the machinery to normal operation, check the mechanical installation, cable condition, connector security, and signal output.

Compare the measured values with expected operating conditions. Abnormal readings should be investigated before the equipment is placed into service.

Compatible System Components

The PR6424/013-101 is typically used as part of a complete eddy current measurement chain.

A compatible system requires the correct combination of sensor, cable, converter, and monitoring hardware. Components should not be selected solely because they belong to the same product family.

Alternative Models and Replacement Considerations

The PR6424 series includes different sensor configurations. Although several models share a 16 mm sensing diameter, their cable arrangements, probe lengths, mounting options, and connector configurations may differ.

Before replacing the PR6424/013-101, compare the following:

• Complete model number and suffix.
• Sensor head diameter.
• Probe body length and thread.
• Cable length and construction.
• Connector type.
• Static and dynamic measurement ranges.
• Sensitivity and linearity.
• Target material and calibration.
• Operating temperature.
• Compatible signal converter.
• Monitoring system input requirements.

A replacement probe should match the original measurement chain. Using a sensor with a different calibration or cable configuration may result in incorrect readings even when the physical dimensions appear similar.

Key Advantages

Non-Contact Measurement

The sensor measures shaft movement without physical contact, avoiding mechanical wear between the probe and the rotating target.

Shaft Vibration Monitoring

The PR6424 family supports dynamic measurement of shaft movement, providing information for rotating machinery condition monitoring.

Static Displacement Measurement

Its static measurement capability allows monitoring of shaft position and displacement within the specified range.

Compact 16 mm Sensor Head

The 16 mm sensing diameter supports installation in suitable machinery locations where probe clearance and mounting space must be considered.

Industrial Temperature Capability

The PR6424 family is designed for demanding industrial environments, with a published operating temperature range of -35°C to +180°C.

High Measurement Sensitivity

The published sensitivity of 4 V/mm supports measurement of small changes in the distance between the probe and the target.

Integration with Machinery Monitoring Systems

When paired with the appropriate converter and monitoring equipment, the sensor can provide measurement information for machinery condition assessment and protection.

Technical FAQs

1. What is the EPRO PR6424/013-101?

It is a 16 mm eddy current sensor from the EPRO PR6424 series. It is designed for non-contact measurement of shaft displacement and vibration in rotating machinery.

2. What is the sensor head diameter?

The nominal sensor head diameter is 16 mm.

3. What is the measurement principle?

The sensor uses eddy current technology. An electromagnetic field generated at the probe tip interacts with the conductive shaft surface, and changes in the electrical response are used to determine the distance between the probe and target.

4. What is the static measurement range?

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

5. What is the dynamic measurement range?

The PR6424 family dynamic measurement range is 0–1,000 μm peak-to-peak.

6. What is the sensitivity of the PR6424 series?

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

7. Which materials can the sensor measure?

The standard calibration reference is ferromagnetic steel, specifically 42CrMo4. Different target materials may affect measurement performance and should be evaluated during system configuration.

8. Does the sensor work independently?

The probe is normally used with a compatible extension cable and signal converter. The converter processes the sensor signal for connection to machinery monitoring equipment.

9. What is the weight of the PR6424 sensor?

The supplied listing weight is 0.2 kg. The published family specification gives approximately 200 grams for the sensor and a 1-meter cable without armor.

10. Where is the PR6424/013-101 commonly used?

Typical application areas include steam turbines, gas turbines, hydro turbines, compressors, pumps, fans, and other critical rotating machinery.

11. Can it replace another PR6424 model?

Not automatically. The complete model suffix, cable construction, connector, probe length, calibration, and converter compatibility should be checked before substitution.

12. What should be checked before purchasing?

Confirm the complete model number, sensor head condition, cable and connector configuration, mounting thread, measurement range, and compatibility with the existing signal converter.

Procurement and Maintenance Recommendations

When purchasing the EPRO PR6424/013-101, verify the complete model number and confirm that the supplied sensor matches the original equipment configuration.

For replacement projects, pay particular attention to the probe’s cable arrangement and signal converter compatibility. A sensor with the correct 16 mm head diameter may still be unsuitable if its electrical configuration or calibration differs from the existing measurement chain.

For used or surplus equipment, inspect the sensing tip, threaded sleeve, cable insulation, connector, and identification label. Check for visible mechanical damage, corrosion, cable deformation, or signs of improper storage.

During routine maintenance, inspect the probe mounting position and cable routing. Make sure the sensor remains securely installed and that the cable is protected from excessive bending, heat, abrasion, and mechanical interference.

Keep records of the initial air gap, calibration information, monitoring values, and replacement history. These records can help maintenance personnel identify changes in sensor performance and distinguish instrumentation problems from actual machinery faults.

For critical turbine and compressor applications, replacement and commissioning should follow the machinery protection system’s technical requirements and the applicable manufacturer procedures.

Conclusion

The EPRO PR6424/013-101 16mm Eddy Current Sensor is designed for non-contact shaft displacement and vibration measurement in critical rotating machinery. Based on the published PR6424 family specifications, it provides a static measurement range of ±2.0 mm, a dynamic range of 0–1,000 μm, and a sensitivity of 4 V/mm.

Its compact 16 mm sensing head and non-contact measurement principle make the PR6424 series suitable for use in turbines, compressors, pumps, fans, and other industrial rotating equipment.

For procurement and maintenance, confirming the exact /013-101 cable configuration, connector, probe dimensions, calibration, and signal converter compatibility is essential to ensure reliable integration into the existing machinery monitoring system.