Product Overview

The Epro PR6424/008-030 16 mm Eddy Current Sensor is a non-contact displacement measurement probe designed for monitoring the operating condition of critical rotating machinery. It belongs to the EPRO PR6424 sensor family, which is used in industrial machinery protection and condition monitoring applications.

The sensor is designed to measure changes in the distance between its sensing tip and a conductive target, typically a ferromagnetic steel shaft. By detecting variations in this gap, the sensor system can provide information about shaft vibration, radial and axial displacement, shaft position, eccentricity, and rotational speed-related conditions.

Unlike contact-based measurement devices, an eddy current sensor does not need to physically touch the rotating shaft. This makes it suitable for continuous monitoring in equipment where mechanical contact could cause wear, interfere with operation, or damage the measurement device.

The PR6424 series is commonly used in steam turbines, gas turbines, compressors, pumps, fans, and other rotating equipment. These machines often operate continuously and require reliable condition monitoring to help maintenance personnel identify abnormal shaft movement and changing mechanical conditions.

The PR6424/008-030 has a 16 mm sensor head diameter and a supplied listing weight of 0.2 kg. Its compact sensing head supports installation in machinery monitoring locations where probe clearance and mounting geometry must be considered.

The sensor is normally used as part of a complete measurement system. Depending on the system configuration, this includes the probe, a compatible extension cable, a signal converter, and a monitoring or protection device. The exact cable length, connector arrangement, and mounting configuration should be checked against the complete catalog number before installation or replacement.

Technical Specifications

Note: These are PR6424 family reference specifications. Exact cable length, connector type, probe dimensions, and environmental limits must be verified for the specific PR6424/008-030 configuration. The supplied 0.2 kg is retained as the product listing weight.

Function and Working Principle

The PR6424/008-030 uses the eddy current principle to measure the distance between the sensor tip and a conductive target. Its operation is based on electromagnetic interaction rather than physical contact.

1. Eddy Current Measurement Principle

An eddy current probe contains a sensing coil that generates an alternating electromagnetic field. When a conductive metal target, such as a rotating steel shaft, enters this field, electrical currents known as eddy currents are induced in the target surface.

These currents affect the electrical characteristics of the probe coil. As the distance between the sensor and the target changes, the electromagnetic interaction changes as well.

A compatible signal converter processes this change and converts it into an electrical output proportional to the measured gap.

This allows the monitoring system to detect very small changes in shaft position without requiring the probe to touch the rotating surface.

2. Shaft Displacement Measurement

Shaft displacement is an important parameter in rotating machinery monitoring. Excessive radial or axial movement may indicate mechanical wear, bearing problems, misalignment, looseness, or other abnormal operating conditions.

The PR6424 sensor can be installed near the shaft to measure changes in the gap between the probe and the target surface.

When the shaft moves, the distance changes and the sensor system produces a corresponding measurement signal. The monitoring equipment can use this information to evaluate shaft position and movement.

3. Shaft Vibration Monitoring

Shaft vibration measurement helps maintenance teams understand the dynamic behavior of rotating equipment.

The probe detects the movement of the shaft relative to its mounting position. When connected to a compatible converter and monitoring system, the resulting signal can be used to analyze vibration amplitude and changes over time.

This information is particularly useful for turbines, compressors, and other machines where abnormal vibration may indicate developing mechanical problems.

4. Position and Eccentricity Measurement

The sensor can also be used for static position and eccentricity measurements.

Eccentricity describes the deviation of a rotating shaft from its ideal geometric center. Excessive eccentricity can contribute to vibration, uneven loading, and mechanical wear.

By monitoring the gap between the probe and the shaft, the system can identify changes in shaft position and support machinery condition assessment.

5. Speed and Key-Related Monitoring

When installed in an appropriate measurement arrangement, an eddy current sensor can detect changes associated with shaft rotation and reference features on the target.

The resulting signal can be used by compatible monitoring equipment for speed or key-related measurements. The specific function depends on the target geometry, probe arrangement, converter configuration, and monitoring system.

Role in Industrial Machinery Protection Systems

The PR6424/008-030 is a sensing component rather than a standalone machinery protection system. It provides measurement information that must be processed by compatible signal-conditioning and monitoring equipment.

1. Continuous Shaft Condition Monitoring

In critical rotating machinery, shaft movement is an important indicator of mechanical condition. A continuously installed sensor can provide information about operating behavior without requiring repeated manual measurements.

The monitoring system can evaluate the signal and identify changes that may require further investigation.

2. Integration with Signal Converters

The sensor must be connected to a compatible signal converter. The converter supplies the required excitation and processes the probe’s electrical response into a usable measurement signal.

Compatibility is essential. The probe, extension cable, and converter must belong to a supported measurement configuration. Incorrect combinations may result in inaccurate readings, unstable signals, or failure to obtain a valid measurement.

3. Connection to Machinery Monitoring Equipment

The converted signal can be supplied to machinery monitoring equipment for vibration, displacement, or position monitoring.

Depending on the system architecture, the monitoring equipment may provide:

• Shaft vibration measurements.
• Radial displacement information.
• Axial position measurements.
• Shaft eccentricity information.
• Speed-related signals.
• Alarm and trip functions when configured within a protection system.

The sensor itself does not independently make shutdown decisions. Alarm limits and protective actions are determined by the connected monitoring equipment and the plant’s protection design.

4. Support for Predictive Maintenance

Historical sensor measurements can help maintenance personnel identify changes in machinery behavior.

For example, a gradual increase in shaft vibration may indicate that an inspection is necessary. Changes in axial position may also provide information about thrust-bearing behavior or other mechanical conditions.

These measurements are most useful when interpreted together with operating speed, load, temperature, process conditions, and other machinery monitoring data.

Industrial Applications

The PR6424 16 mm sensor family is intended for monitoring critical rotating machinery. Its non-contact measurement principle makes it suitable for applications where shaft movement and position must be monitored continuously.

1. Steam Turbines

Steam turbines are used in power generation and industrial steam systems. Their shafts rotate at high speeds and operate under demanding mechanical and thermal conditions.

Eddy current sensors can monitor shaft vibration and displacement to help identify changes in rotor behavior.

The PR6424 family is suitable for applications where non-contact shaft measurement is required as part of a compatible machinery monitoring system.

2. Gas Turbines

Gas turbines operate under high rotational speeds and demanding operating conditions. Monitoring shaft movement is important for evaluating rotor stability and identifying abnormal mechanical behavior.

A properly installed eddy current measurement system can provide information about shaft vibration and position for machinery protection and maintenance analysis.

3. Industrial Compressors

Centrifugal and other high-speed compressors may require continuous shaft vibration and displacement monitoring.

The sensor can be installed near an appropriate shaft measurement location to detect changes in the gap between the probe and the rotating surface.

This information helps maintenance teams assess mechanical behavior and investigate abnormal vibration conditions.

4. Pumps

Large industrial pumps are widely used in power generation, petrochemical processing, water treatment, and manufacturing.

In critical pump installations, shaft movement monitoring can help identify developing mechanical problems, including bearing deterioration, rotor imbalance, or alignment changes.

5. Industrial Fans

Large fans and ventilation systems may operate continuously in power plants, steel production facilities, and process industries.

Where shaft condition monitoring is required, eddy current sensors can provide non-contact displacement information for the connected monitoring system.

6. Power Generation Equipment

Power generation facilities depend on rotating machinery to maintain stable operation. Turbines, generators, compressors, and associated auxiliary equipment may require continuous vibration and position monitoring.

The PR6424 sensor family can form part of the instrumentation used to monitor these machines and support maintenance planning.

Installation and System Integration

Correct installation is essential for obtaining reliable measurements from the PR6424/008-030. Probe mounting, target material, air gap, cable routing, and signal converter compatibility all influence measurement performance.

1. Confirm the Complete Model Number

Before installation, check the sensor label and confirm the complete model number, including the suffix.

Different PR6424 variants may have different cable lengths, connectors, mounting arrangements, or other configuration details. Do not assume that another PR6424 model has an identical physical or electrical configuration.

2. Select a Suitable Measurement Location

The probe should be mounted at the measurement location specified by the machinery monitoring design.

The target surface should be suitable for eddy current measurement. The PR6424 family is designed for use with ferromagnetic steel targets, with 42CrMo4 commonly used as a reference material in the published specifications.

The installation should also provide sufficient clearance around the probe and avoid interference from nearby metallic objects.

3. Set the Correct Air Gap

The distance between the probe tip and the target surface is a critical installation parameter.

The PR6424 family specifies a nominal center air gap of approximately 2.7 mm. The actual installation gap must be established using the manufacturer’s calibration and installation procedures.

An incorrect gap can reduce measurement accuracy or cause the system to operate outside its intended linear range.

4. Connect the Compatible Extension Cable

The sensor cable must be connected using the correct extension cable and connector arrangement for the specific configuration.

Cable length and connector type should be verified before installation. Avoid excessive bending, pulling, or twisting of the cable.

The cable should be routed away from high-power conductors and other potential sources of electrical interference where practical.

5. Connect the Signal Converter

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

The converter provides the electrical interface needed to process the probe signal. The complete probe-and-converter combination should be checked against the applicable manufacturer documentation.

Do not assume that all PR6424 probes can be connected interchangeably to every converter configuration.

6. Verify the Measurement Signal

After installation, verify the probe gap, wiring, connector condition, and converter configuration.

Check the output signal under the required operating conditions and confirm that it responds correctly to changes in target distance.

The initial measurement should be compared with the expected reference values before the system is accepted for machinery protection or condition monitoring.

Compatible System Components

The PR6424/008-030 is normally used as part of a complete eddy current measurement chain.

The components listed are examples from the broader PR6424 measurement ecosystem. They are not automatically included with the sensor. Confirm the exact compatible converter and extension cable for the /008-030 variant before ordering.

Alternative Models and Replacement Considerations

The PR6424 series includes multiple 16 mm eddy current sensor configurations. Although models may share the same basic measurement principle and sensor-head diameter, they should not be treated as automatically interchangeable.

Before selecting a replacement, compare:

• Complete sensor catalog number.
• Sensor-head diameter and physical length.
• Mounting thread and installation dimensions.
• Cable length and cable construction.
• Connector type and termination.
• Compatible extension cable.
• Compatible signal converter.
• Measurement sensitivity and linearity.
• Target material and operating air gap.
• Environmental and temperature requirements.

A replacement probe should be evaluated as part of the complete measurement chain. Matching only the 16 mm head diameter is not sufficient to guarantee compatibility.

Key Advantages

Non-Contact Measurement

The sensor measures target displacement without physical contact. This is important for rotating machinery where direct contact with the shaft would be unsuitable.

Shaft Vibration Monitoring

The PR6424 family supports dynamic displacement measurement, allowing compatible monitoring systems to evaluate shaft vibration.

Static Position Measurement

The sensor can also measure changes in shaft position and support eccentricity and axial displacement monitoring.

High Measurement Sensitivity

The family specification lists a typical sensitivity of 4 V/mm, supporting the detection of small changes in the probe-to-target gap.

Compact 16 mm Sensor Head

The 16 mm head diameter provides a defined mounting size for machinery installations designed around this probe family.

Industrial Machinery Applications

The sensor family is designed for critical rotating equipment, including turbines, compressors, pumps, and fans.

Integration with Monitoring Systems

When paired with compatible extension cables and signal converters, the probe can provide measurement signals for industrial machinery monitoring and protection systems.

Technical FAQs

1. What is the Epro PR6424/008-030?

The PR6424/008-030 is a 16 mm eddy current sensor designed 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.

3. What is the weight of the PR6424/008-030?

The supplied product listing weight is 0.2 kg.

4. What is the measurement principle?

The sensor uses electromagnetic eddy current technology. Changes in the distance between the probe and a conductive target affect the probe’s electrical characteristics. A compatible converter processes this change into a measurement signal.

5. What is the typical sensitivity of the PR6424 series?

The published family specification gives a typical sensitivity of 4 V/mm, with linearity of up to ±1.5%.

6. What is the static measurement range?

The PR6424 family specification lists a static measurement range of ±2.0 mm.

7. What is the dynamic measurement range?

The published family specification lists a dynamic range of 0–1,000 μm.

8. Which materials can the sensor measure?

The PR6424 family is designed for conductive ferromagnetic targets. Ferromagnetic steel is the reference target material in the published specifications.

9. Does the sensor work independently?

No. It normally operates with a compatible extension cable and signal converter. The converter processes the probe response and provides a usable signal for the monitoring equipment.

10. Can the PR6424/008-030 be used for turbine monitoring?

Yes. The PR6424 family is designed for critical rotating machinery applications, including steam and gas turbines, provided the probe is correctly selected, installed, and integrated.

11. Can another PR6424 model replace the /008-030?

Not automatically. Different suffixes may indicate different cable, connector, or mounting configurations. Verify the complete model and system compatibility before replacement.

12. What should be checked if the measurement signal becomes unstable?

Check the probe mounting, air gap, target surface, cable condition, connectors, grounding, and signal converter configuration. Also verify that the probe and converter are a supported combination.

Procurement and Maintenance Recommendations

When purchasing the Epro PR6424/008-030, verify the complete model number and compare it with the sensor currently installed in the machinery. The 16 mm head diameter alone is not sufficient to identify the correct replacement.

For industrial spare-parts procurement, confirm the cable arrangement, connector type, mounting thread, probe length, and compatible signal converter. Request clear photographs of the product label and physical connections when sourcing replacement or surplus units.

During installation, follow the manufacturer’s procedures for probe positioning and air-gap adjustment. The sensor should be mounted securely, with suitable cable protection and routing.

For maintenance, periodically inspect the probe, cable, connector, and mounting hardware. Check for mechanical damage, contamination, loose connections, and changes in the measurement signal.

If the sensor is part of a machinery protection system, preserve the original configuration records and calibration information. After replacing a probe, verify the complete measurement chain before returning the equipment to normal operation.

Conclusion

The Epro PR6424/008-030 16 mm Eddy Current Sensor is designed for non-contact shaft displacement and vibration monitoring in critical industrial rotating machinery. Its compact 16 mm sensor head and the PR6424 family’s published measurement characteristics make it suitable for integration into compatible machinery condition monitoring systems.

With a typical sensitivity of 4 V/mm, a static measurement range of ±2.0 mm, and a dynamic measurement range of 0–1,000 μm, the PR6424 family supports the monitoring of shaft movement, position, and vibration.

For replacement and maintenance projects, the complete model suffix, cable configuration, connector, and signal converter compatibility should always be verified. Correct installation and system calibration are essential for obtaining reliable measurement results.