Product Overview

The EPRO PR6424/009-030 16 mm Eddy Current Sensor is a non-contact displacement sensor designed for monitoring the condition and operating behavior of rotating industrial machinery. It belongs to the PR6424 sensor family, developed for applications that require accurate measurement of shaft vibration, displacement, position, and eccentricity.

The PR6424 series is associated with EPRO machinery protection and condition-monitoring solutions from Emerson. It is commonly used in critical rotating equipment, including steam turbines, gas turbines, hydro turbines, compressors, pumps, and industrial fans.

Unlike contact-based measurement devices, an eddy current sensor measures the distance between its sensing tip and a conductive target without physically touching the target surface. This makes it suitable for continuous shaft monitoring, where direct contact could cause wear or interfere with machine operation.

The PR6424/009-030 has a nominal sensor head diameter of 16 mm. Its measurement characteristics make it useful for detecting small changes in shaft position and dynamic movement. When connected to a compatible signal converter and monitoring system, it can provide measurement information for machinery protection, condition monitoring, and maintenance analysis.

The supplied product data lists a weight of 0.2 kg. This is consistent with the approximate reference weight published for the PR6424 sensor with a 1-meter cable and without armor. Actual weight may vary with cable length, armor, connector, and supplied accessories.

Technical Specifications

Note: The specifications above describe the PR6424 sensor family. Cable length, connector type, armor, thread configuration, and other suffix-specific details should be verified against the nameplate and documentation for the exact PR6424/009-030 unit.

Function and Working Principle

The PR6424/009-030 uses the eddy current measurement principle to detect the distance between its sensor tip and a conductive metal target.

When the sensor is connected to a compatible signal converter, the probe generates an electromagnetic field. As a conductive target approaches or moves away from the sensing tip, the electromagnetic interaction changes. The resulting electrical response is processed by the converter to produce a measurement signal related to the target distance.

1. Non-Contact Displacement Measurement

The sensor measures the gap between the probe and the rotating shaft without requiring physical contact.

This is important in high-speed machinery, where the shaft surface moves continuously and mechanical contact could introduce wear or measurement errors.

The resulting displacement information can be used to monitor shaft position and detect abnormal movement.

2. Shaft Vibration Monitoring

Rotating shafts may experience vibration due to imbalance, misalignment, bearing wear, looseness, or other mechanical conditions.

The PR6424 can measure dynamic shaft movement within its specified measurement range. When used with an appropriate converter and monitoring system, the measurement can support vibration analysis and machinery protection.

3. Axial Position Monitoring

The sensor can be installed to measure axial shaft displacement where the mechanical arrangement and installation design are suitable.

Changes in axial position may indicate thrust-bearing problems, mechanical movement, or changes in operating conditions. Continuous monitoring helps maintenance personnel identify abnormal trends before they develop into more serious equipment problems.

4. Eccentricity Measurement

Shaft eccentricity refers to the difference between the geometric center and the actual rotational center of a shaft.

The PR6424 can be used to monitor shaft position and eccentricity in compatible rotating machinery. This information is useful during startup, shutdown, and normal operating conditions.

5. Speed and Key-Related Measurements

With an appropriate target arrangement and monitoring configuration, the PR6424 measurement system can also support speed- and key-related monitoring functions.

The sensor installation and signal-processing equipment must be selected according to the intended measurement task.

Role in Industrial Machinery Protection Systems

The PR6424/009-030 is typically used as part of a complete machinery monitoring arrangement rather than as an independent monitoring instrument.

A typical measurement chain includes the sensor probe, an extension cable where required, a compatible signal converter, and a monitoring or protection system.

Sensor Probe

The sensor is installed near the rotating shaft with a carefully controlled air gap. Its function is to detect changes in the distance between the probe tip and the shaft surface.

Correct mounting position, target material, and gap adjustment are essential for reliable measurement.

Signal Converter

The probe must be paired with a compatible converter, such as an appropriate CON-series unit. The converter conditions the probe signal and provides a usable output for monitoring equipment.

Compatibility should be checked for the exact probe configuration, connector, cable arrangement, and converter model.

Monitoring System

A machinery monitoring system receives the conditioned measurement signal and evaluates the operating condition of the equipment.

Depending on the system configuration, the information can be used for:

• Shaft vibration monitoring.
• Axial displacement monitoring.
• Shaft position measurement.
• Eccentricity monitoring.
• Alarm and trip functions.
• Historical condition analysis.
• Maintenance planning.

The sensor itself does not independently provide all alarm, protection, or diagnostic functions. These depend on the connected monitoring equipment and its configuration.

Industrial Applications

The PR6424/009-030 is designed for applications involving large rotating machinery and continuous measurement of shaft movement.

1. Steam Turbines

Steam turbines operate under high mechanical and thermal loads. Continuous monitoring of shaft vibration and displacement is important for identifying changes in operating condition.

The PR6424 can be installed at suitable measurement locations to monitor shaft movement and provide information to the turbine protection system.

2. Gas Turbines

Gas turbines require reliable monitoring because abnormal vibration or shaft displacement can affect mechanical stability and equipment availability.

Non-contact measurement allows the sensor to monitor shaft movement without contacting the rotating surface.

3. Hydro Turbines

Hydro turbine installations may operate continuously for long periods. Shaft vibration and displacement monitoring can help identify mechanical changes and support planned maintenance.

The PR6424 series is suitable for selected hydro turbine monitoring applications where its measurement range and installation configuration meet the requirements.

4. Industrial Compressors

Compressors are used in chemical processing, oil and gas facilities, power plants, and manufacturing operations.

The sensor can monitor radial and axial shaft movement in compatible compressor installations. Measurement information can help maintenance teams evaluate changes in machine condition.

5. Industrial Pumps

Large industrial pumps may experience vibration caused by bearing wear, shaft misalignment, hydraulic conditions, or mechanical imbalance.

When installed at suitable locations, the PR6424 can provide non-contact shaft displacement measurements for condition monitoring.

6. Industrial Fans

Large fans used in power generation and process industries may require continuous vibration monitoring.

The sensor can be incorporated into an appropriate monitoring system to track shaft movement and support maintenance decisions.

Installation and System Integration

Correct installation is essential for obtaining stable and accurate measurements from the PR6424/009-030.

1. Select the Correct Measurement Location

Choose a suitable location near the shaft where the sensor can measure the intended movement.

The installation must provide sufficient clearance for the sensor body and cable. Avoid positions where the probe may contact rotating components during normal operation or under abnormal mechanical movement.

2. Confirm the Target Material

The PR6424 series is designed to measure suitable ferromagnetic targets. The target material and surface condition influence measurement performance.

The manufacturer’s reference target material is ferromagnetic steel, with 42CrMo4 identified as a standard material.

If the shaft uses a different material or surface treatment, verify measurement compatibility before installation.

3. Set the Correct Air Gap

The nominal center air gap for the PR6424 series is approximately 2.7 mm.

The gap must be adjusted according to the manufacturer’s installation procedure and the selected converter configuration.

Incorrect gap adjustment can reduce measurement accuracy, cause signal saturation, or result in unreliable readings.

4. Connect the Compatible Signal Converter

The sensor must be connected to a compatible signal converter. Confirm the required converter type, connector arrangement, cable length, and system configuration.

Do not assume that all PR6424 variants use identical cable and connector arrangements.

5. Route and Protect the Cable

The sensor cable should be routed away from sources of electrical interference, excessive heat, mechanical abrasion, and moving equipment.

Observe the specified minimum bending radius and ensure that the cable is properly secured. Avoid unnecessary cable extensions or connector changes that could affect signal quality.

6. Verify the Measurement Signal

After installation, check the sensor gap, cable connections, converter supply, and output signal.

Confirm that the measurement responds correctly to changes in shaft position and that the signal remains stable under the expected operating conditions.

Document the installation gap and baseline measurement values for future maintenance comparisons.

Compatible System Components

The PR6424/009-030 normally operates as part of a complete machinery measurement system.

The components listed above are examples of equipment used in PR6424 measurement arrangements. They are not necessarily included with the sensor.

Alternative Models and Replacement Considerations

The PR6424 belongs to the EPRO eddy current sensor family. Other sensor models may offer similar measurement functions, but they are not automatically interchangeable.

Before replacing the PR6424/009-030, compare the following:

• Sensor head diameter.
• Probe body dimensions and mounting thread.
• Cable length and cable construction.
• Connector type.
• Static and dynamic measuring ranges.
• Sensitivity and linearity.
• Operating temperature.
• Target material and shaft diameter.
• Signal converter compatibility.
• Monitoring-system input requirements.

A replacement probe should not be selected based on sensor diameter alone. Electrical characteristics, mounting dimensions, converter compatibility, and measurement performance must all be considered.

Key Advantages

Non-Contact Measurement

The sensor measures shaft displacement without touching the rotating surface, avoiding mechanical contact during normal operation.

High Measurement Sensitivity

The PR6424 series provides a sensitivity of 4 V/mm, supporting the measurement of small changes in shaft position.

Suitable for Critical Rotating Machinery

The sensor family is designed for applications involving turbines, compressors, pumps, and fans.

Static and Dynamic Measurement

The sensor supports static position measurements and dynamic displacement measurements within its specified operating range.

Industrial Construction

The stainless steel sleeve and PTFE cable construction are intended for demanding industrial measurement environments.

Integration with Machinery Monitoring Systems

When paired with a compatible converter, the probe can provide measurement information to machinery protection and condition-monitoring equipment.

Maintenance Support

Continuous shaft displacement and vibration measurements can help maintenance personnel identify abnormal operating trends and plan inspections.

Technical FAQs

1. What is the EPRO PR6424/009-030?

It is a 16 mm eddy current sensor designed for non-contact measurement of shaft displacement, vibration, position, and eccentricity in rotating machinery.

2. What is the sensor head diameter?

The sensor head diameter is 16 mm.

3. What is the measuring range of the PR6424 series?

The standard static measurement range is ±2.0 mm. The dynamic measurement range is specified as 0 to 1,000 μm.

4. What is the sensitivity?

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

5. What is the nominal air gap?

The nominal center air gap is approximately 2.7 mm. Final adjustment should follow the manufacturer’s installation instructions.

6. Does the sensor need a signal converter?

Yes. The sensor is normally used with a compatible signal converter that conditions the probe signal for the monitoring system.

7. What equipment can use this sensor?

Typical applications include steam turbines, gas turbines, hydro turbines, compressors, pumps, and industrial fans.

8. What is the weight of the PR6424/009-030?

The supplied product weight is 0.2 kg. The manufacturer’s reference weight is approximately 200 grams for a sensor with a 1-meter cable and no armor. Actual weight may vary with the supplied cable and accessories.

9. Can the PR6424/009-030 replace another PR6424 model?

Not automatically. Different suffixes may identify different cable lengths, connector arrangements, body configurations, or other options. Verify the complete model number before substitution.

10. What should be checked if the sensor signal is unstable?

Inspect the probe gap, target surface, cable condition, connector contacts, converter compatibility, grounding, and signal wiring. Also check for electrical interference and mechanical vibration outside the expected operating range.

Procurement and Maintenance Recommendations

When purchasing the EPRO PR6424/009-030, verify the complete model number and compare it with the installed sensor’s identification label.

The PR6424 family includes multiple configurations. Cable length, armor, connector type, probe body, and other options may differ between suffixes. A sensor with the same 16 mm diameter is not necessarily a direct replacement.

For used or surplus units, request clear photographs of the probe, cable, connector, and identification label. Check the cable jacket for cracks, cuts, or deformation and inspect the sensor body for mechanical damage.

During installation, follow the manufacturer’s instructions for probe mounting, air-gap adjustment, cable routing, and converter connection. Record the initial measurement values so that future readings can be compared against a known baseline.

For critical machinery, the sensor should be maintained as part of the complete monitoring system. Periodically inspect the probe, extension cable, connectors, converter, and monitoring-system input to help maintain measurement reliability.

Conclusion

The EPRO PR6424/009-030 16 mm Eddy Current Sensor is designed for non-contact shaft displacement and vibration measurement in critical rotating machinery. With a 16 mm sensor head, 4 V/mm sensitivity, and a standard static measurement range of ±2.0 mm, it supports machinery condition monitoring in turbines, compressors, pumps, and industrial fans.

For replacement and maintenance applications, buyers should verify the complete suffix, cable arrangement, connector type, and compatible signal converter. Correct installation and air-gap adjustment are essential for obtaining reliable measurement results.