Product Overview

The Epro PR6424/010-040 + CON021/916-160 Eddy Current Sensor Assembly is listed as a non-contact displacement measurement solution for industrial rotating machinery. Epro eddy current sensor technology is used in machinery condition monitoring systems to measure shaft vibration, axial displacement, radial movement, eccentricity, and other dynamic mechanical conditions.

The PR6424 series is designed for demanding applications involving turbines, compressors, pumps, fans, and other rotating equipment. Unlike contact-based measurement devices, an eddy current sensor measures the distance between its probe tip and a conductive target without physically touching the rotating shaft. This allows continuous monitoring without introducing mechanical contact between the sensor and the measured surface.

The PR6424 sensor uses an electromagnetic measurement principle. A high-frequency signal in the probe generates an electromagnetic field. When a conductive target approaches the probe, the field changes, and the resulting electrical response is processed into a signal proportional to the distance between the probe and the target.

This measurement principle is particularly useful in machinery protection systems, where small changes in shaft position or vibration can provide important information about equipment operating conditions.

The listed configuration includes a PR6424/010-040 sensor and a CON021/916-160 converter designation. However, the converter suffix requires careful verification. Emerson’s CON021 selection documentation identifies the /916-160 extended-range converter as a configuration for PR6426 sensors, while the PR6424 is a different sensor family. Therefore, the compatibility of this exact combination should be confirmed before installation or purchase.

For maintenance engineers and procurement specialists, checking the complete probe and converter part numbers is essential. A sensor and converter should be selected as a calibrated combination rather than treated as interchangeable components based only on connector type.

Technical Specifications

Important: The listed converter designation should be checked against the probe’s official calibration and compatibility documentation. The specifications above describe the PR6424 sensor family where supported by the manufacturer’s documentation; they should not be interpreted as confirmation that the complete listed combination is a factory-matched assembly.

Function and Working Principle

The PR6424 operates through the eddy current measurement principle. It is designed to measure the distance between the sensor tip and a conductive target, commonly a rotating machinery shaft.

1. Electromagnetic Field Generation

The sensor probe contains an electrical coil that generates a high-frequency electromagnetic field when energized by a compatible signal converter.

When the probe is positioned near a conductive metal target, the electromagnetic field induces eddy currents in the target surface. These currents influence the electrical characteristics of the probe coil.

The resulting change provides the measurement information used to determine the distance between the probe and the target.

2. Non-Contact Displacement Measurement

The sensor measures displacement without direct physical contact with the rotating shaft. This is important for equipment operating at high speeds, where a contact-based measuring device would be unsuitable.

As the shaft moves relative to the probe, the distance changes. The sensor system converts these changes into an electrical signal that can be interpreted by a compatible monitoring device.

This allows machinery operators to monitor shaft movement continuously while the equipment remains in operation.

3. Signal Conversion

The probe requires a compatible signal converter to provide excitation and process its measurement signal. The converter linearizes the sensor response and supplies an output suitable for the connected monitoring system.

The converter must match the sensor model, measuring range, calibration characteristics, and cable arrangement. Using an incorrectly configured converter may produce inaccurate measurements or an unsuitable output signal.

For this reason, the CON021/916-160 designation in this listing should be checked carefully against the PR6424 probe. The manufacturer identifies that extended-range converter configuration with PR6426 sensors.

4. Vibration and Position Monitoring

Once correctly installed and calibrated, the sensor system can provide information about shaft movement and vibration.

Monitoring systems can use this information to identify changes in machinery condition, including abnormal vibration, shaft displacement, and changes in operating behavior.

These measurements are useful for condition monitoring and machinery protection, especially in equipment where mechanical reliability is critical.

Role in Industrial Machinery Monitoring Systems

The PR6424 is designed to operate as part of a complete machinery monitoring arrangement. It is not normally used as an independent control device. Instead, it provides measurement information to a compatible signal converter and monitoring system.

Shaft Vibration Monitoring

Shaft vibration is an important indicator of rotating machinery condition. Changes in vibration may be associated with rotor imbalance, misalignment, bearing deterioration, looseness, or other mechanical problems.

A properly installed eddy current probe can measure relative shaft movement and provide data for vibration analysis.

Axial Position Monitoring

Axial displacement measurement is important in turbines, compressors, and other rotating machines where the rotor must remain within an acceptable axial operating range.

The sensor can be installed to monitor changes in shaft position relative to a fixed reference point. The measurement can then be evaluated by a machinery protection system.

Eccentricity Measurement

Shaft eccentricity describes variation in the position of a rotating shaft relative to its rotational center. Monitoring eccentricity can help engineers evaluate rotor condition and identify mechanical changes.

The PR6424’s non-contact measurement principle makes it suitable for applications requiring continuous observation of shaft displacement.

Integration with Machinery Protection Systems

The sensor’s output can be connected to a compatible monitoring platform through the appropriate converter and interface.

Depending on the installed monitoring architecture, measurement data may be used for alarms, shutdown logic, trend analysis, and maintenance planning.

The complete system must be configured according to the sensor’s calibration, converter characteristics, monitoring-channel requirements, and machinery protection design.

Industrial Applications

The PR6424 series is intended for critical rotating machinery applications where continuous displacement and vibration measurement are important.

1. Steam Turbines

Steam turbines operate under demanding mechanical and thermal conditions. Continuous shaft monitoring helps operators evaluate rotor movement and identify abnormal vibration behavior.

Eddy current sensors can be used for radial shaft vibration and axial position measurements when installed in a properly engineered monitoring system.

2. Gas Turbines

Gas turbines operate at high rotational speeds and require reliable monitoring of rotating components.

Non-contact displacement sensors can provide information about shaft movement and vibration, supporting machinery protection and condition assessment.

3. Industrial Compressors

Compressors are widely used in petrochemical plants, refineries, gas processing facilities, and manufacturing operations.

Monitoring shaft vibration and axial position can help maintenance teams identify abnormal operating conditions before they develop into more serious equipment problems.

4. Industrial Pumps

Large process pumps may operate continuously in water treatment, power generation, chemical processing, and oil and gas facilities.

Eddy current sensors can support condition monitoring by measuring relative shaft displacement and vibration in suitable pump configurations.

5. Industrial Fans

Large fans and ventilation equipment may operate for extended periods under varying load conditions.

Shaft vibration monitoring can help detect mechanical imbalance, alignment problems, and other changes that may affect equipment reliability.

6. Power Generation Equipment

Power generation facilities rely on rotating machinery such as turbines, generators, and auxiliary equipment.

Non-contact shaft monitoring provides useful information for machinery condition assessment and protection strategies.

Installation and System Integration

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

1. Verify Probe and Converter Compatibility

Before installation, confirm that the PR6424 probe and the selected CON021 converter are an approved combination.

The listed CON021/916-160 designation is associated with PR6426 extended-range configurations in Emerson’s ordering documentation. Do not assume it is suitable for the PR6424/010-040 probe without written confirmation from the manufacturer or an authorized technical source.

Check the complete part numbers, measuring range, calibration target, cable length, connector type, and converter output specifications.

2. Select the Correct Mounting Position

The probe must be installed at the measurement location specified by the machinery monitoring design.

For shaft vibration measurement, the probe is normally positioned near the shaft surface with a carefully controlled initial gap.

For axial displacement monitoring, the probe must be aligned with the appropriate target surface and installed according to the machinery manufacturer’s measurement arrangement.

3. Maintain the Correct Air Gap

The distance between the probe tip and the target surface affects measurement accuracy.

The PR6424 specification identifies a nominal center air gap of approximately 2.7 mm. The actual installation gap must follow the calibration requirements of the specific probe and converter combination.

Incorrect gap adjustment may cause measurement errors, signal saturation, or insufficient measuring range.

4. Check the Target Surface

Eddy current sensors require a suitable electrically conductive target. The manufacturer’s PR6424 specification uses ferromagnetic steel as the standard target material.

Surface material, shaft diameter, surface finish, and target geometry can influence measurement behavior.

The target should meet the requirements of the selected sensor calibration.

5. Route and Protect the Cable

The probe cable should be routed to avoid mechanical damage, excessive bending, heat exposure beyond its specified rating, and interference from high-power electrical conductors.

The PR6424 family uses PTFE cable insulation. The cable connection between the probe and converter must use the correct connector and extension arrangement.

6. Calibrate and Test the Measurement Channel

After installation, verify the sensor gap and converter configuration. Confirm that the output changes correctly as the distance between the probe and target changes.

Check the monitoring channel’s zero point, measuring range, alarm thresholds, and signal scaling before placing the machinery into service.

Record the final installation dimensions and calibration settings for future maintenance.

Compatible System Components

The PR6424 is typically installed as part of a complete machinery monitoring system. Component selection should be based on the exact sensor configuration and manufacturer compatibility documentation.

The listed components are examples of a complete measurement installation. They are not necessarily supplied with the sensor assembly.

Alternative Models and Replacement Considerations

When replacing an Epro PR6424 sensor, selecting another probe based only on diameter or physical appearance is not sufficient. The sensor, converter, cable, and monitoring channel must be compatible.

Before selecting a replacement, compare:

• Probe diameter and mounting thread.
• Complete probe catalog number.
• Cable length and cable construction.
• Converter model and measuring-range suffix.
• Calibration target material.
• Sensitivity and linearity.
• Static and dynamic measuring range.
• Operating temperature.
• Connector type and cable arrangement.
• Monitoring-system input requirements.

A PR6424 probe should not automatically be replaced with a PR6426 probe, or vice versa. Their measurement characteristics and converter configurations must be checked before substitution.

Key Advantages

Non-Contact Measurement

The eddy current principle measures shaft displacement without direct physical contact. This is suitable for continuously operating rotating machinery.

Continuous Shaft Monitoring

The sensor can provide displacement information for machinery condition monitoring and protection systems.

Suitable for Critical Rotating Equipment

The PR6424 series is designed for applications involving turbines, compressors, pumps, and fans.

High-Resolution Displacement Measurement

The documented PR6424 sensitivity of 4 V/mm and linearity of up to ±1.5% support measurement of relatively small changes in shaft position when the complete system is correctly configured.

Industrial Environmental Design

The sensor uses a stainless-steel sleeve and PTFE cable construction. These materials are intended for demanding industrial measurement environments within the specified operating limits.

Integration with Monitoring Systems

When paired with the correct converter, the sensor can provide measurement signals for machinery monitoring and protection equipment.

Technical FAQs

1. What is the Epro PR6424/010-040?

The PR6424/010-040 is a 16 mm eddy current sensor configuration designed for non-contact measurement of shaft displacement and vibration in rotating machinery.

2. What does an eddy current sensor measure?

It measures the distance between the sensor probe and a conductive target. In rotating machinery applications, this measurement can be used to evaluate shaft vibration, radial displacement, axial position, and eccentricity.

3. What is the sensor head diameter?

The listed sensor head diameter is 16 mm.

4. What is the sensitivity of the PR6424?

The manufacturer’s PR6424 specification identifies a sensitivity of 4 V/mm, with linearity of up to ±1.5%.

5. What is the static measuring range?

The documented PR6424 static measuring range is ±2.0 mm. The dynamic range is specified as 0 to 1,000 μm.

6. What material should be used as the measurement target?

The standard PR6424 calibration target is ferromagnetic steel. The target material and geometry should meet the manufacturer’s calibration requirements.

7. Can the PR6424 be used with a CON021 converter?

The PR6424 family is supported by the CON021 converter family in specified configurations. However, the exact converter suffix must match the sensor and required measuring range.

8. Is CON021/916-160 compatible with PR6424/010-040?

This combination requires verification. Emerson’s ordering information identifies CON021/916-160 as a 16.0 mm extended-range configuration for PR6426 sensors, not PR6424. Confirm the complete assembly with the supplier before installation.

9. Where is the PR6424 commonly used?

Typical applications include steam turbines, gas turbines, compressors, pumps, fans, and other rotating machinery requiring shaft displacement or vibration monitoring.

10. What should be checked before purchasing this assembly?

Verify the complete probe and converter part numbers, calibration range, cable length, connector arrangement, sensor condition, and compatibility with the installed machinery monitoring system.

Procurement and Maintenance Recommendations

When purchasing the Epro PR6424/010-040 + CON021/916-160 assembly, the first priority should be confirming the complete part-number combination. The converter suffix is important because it identifies the intended sensor family and measuring range.

Request clear photographs of the probe identification label, converter label, connectors, and cable assembly. Confirm whether the quoted item includes the sensor only, the converter, extension cable, or a complete measurement channel.

For replacement projects, compare the original equipment’s calibration requirements and monitoring-channel configuration. A probe with the same diameter may still have different electrical characteristics or cable arrangements.

During maintenance, inspect the probe tip, cable insulation, connectors, mounting hardware, and cable routing. Check the sensor gap and verify measurement-channel calibration according to the machinery protection system’s maintenance procedure.

After installation, record the probe position, converter model, calibration information, and monitoring-channel settings. These records help maintenance teams diagnose measurement problems and source the correct replacement components.

Conclusion

The Epro PR6424/010-040 is a 16 mm non-contact eddy current sensor designed for shaft displacement and vibration monitoring in critical rotating machinery. Its measurement principle supports continuous monitoring of turbines, compressors, pumps, fans, and other industrial equipment.

The listed assembly also identifies a CON021/916-160 converter configuration. Since the manufacturer associates this converter suffix with PR6426 sensors, its compatibility with the PR6424/010-040 probe must be confirmed before use.

For industrial procurement and maintenance, verifying the complete sensor and converter configuration is essential to achieving reliable measurement performance and maintaining compatibility with the existing machinery monitoring system.