High Precision Gap Monitoring in Plant and Machinery

With the eddyNCDT 3060, Micro-Epsilon has formulated a robust displacement measuring system based on the eddy current principle, integrating accuracy, speed and temperature stability in a novel manner. These characteristics are complemented with optimal accessibility and a competitive price/performance ratio. The system exhibits its strengths particularly with gap measurements in severe ambient conditions.

The eddyNCDT 3060 system is tailored for displacement and distance calculations. As a result of its tough design and precise measurement accuracy, the system is used to supervise the lubricating gap and thermal expansion, as well as to diagnose shaft movement and radial run out of machine parts and drive components.

Factory-calibrated for either ferromagnetic or non-ferromagnetic materials, the inductive displacement measuring system comprises a compact controller, a sensor and a cable. With over 400 compatible sensor models, high speed and smart signal processing, the eddyNCDT 3060 product series from Micro-Epsilon exemplifies a new performance class in inductive displacement measurement.

The formidable eddyNCDT 3060 eddy current displacement measuring system is perfect for rapid, non-contact displacement measurements onto metallic targets. As sensor and controller are assiduously temperature-compensated, extremely high measurement accuracies down to the micrometer range can be attained even in oscillating temperatures.

The sensors are designed to operate effectively in ambient temperatures up to a maximum of +200 °C, and under an ambient pressure of up to 20 bar. The measurements are captured at a frequency response up to 20 kHz. Moreover, the compact controller design, coupled with the fieldbus connection, permits straightforward integration into machines and systems.

Individual Adaption Possibilities

Another noteworthy particularity attribute is the distance-independent multi-point calibration which empowers the customer to transact field linearization on top of the factory-calibration. The measurement accuracy can even be amplified using the DT3061 controller model for a 5-point linearization.

Furthermore, the DT3061 affords switching outputs and temperature outputs, enabling the storage of manifold characteristic curves. Parameter set up is undertaken using a contemporary, user-friendly web interface that is accessed via an Ethernet interface.

Gap Analysis in Axial Piston Pumps

The eddyNCDT 3060 eddy current measuring system also reveals its capacities when investigating the fissures in axial piston pumps. During this process, sensors examine the gasket gaps in extremely limited space, throughout exposure to extreme rotational speeds and severe ambient conditions. Axial piston pumps transmute mechanically generated kinetic energy into hydraulic energy.

Consequently, they are regularly used in slow-moving machines that, in addition to their motion, simultaneously execute hydraulic movements such as lifting, turning or gripping, for example via blades or crane booms. Inside the pump, a cylinder with a piston revolves between two fixed plates in order to accumulate hydraulic pressure. These plates can be implemented to control the necessary pressure by modulating the flow opening.

To verify that the connected mechanical parts can rotate optimally and for maximum duration, friction should be negligible. Therefore, narrow gaps between the components guarantee the principal sliding properties. The majority of these gaps are less than 20 microns wide, and are periodically even less than 10 microns. Besides lowering friction, these so-called sealing gaps are also engaged with maintaining the circulation of the hydraulic oil, and therefore significantly influence the mode of operation of the machines. Changes in the gap can instill pressure loss or a pump failure. The behavior of the gap is thus assessed on the test rig in order to optimize the design of the pump.

To date, gap calculations inside the pumps were not possible because of the extreme conditions. Furthermore, because the pumps are exceptionally compact, they exert considerable restrictions on the space available for the integration of sensors. Conversely, the sensors now employed deliver precise results even when exposed to intense rotational speeds, high pressures and temperatures exceeding 100 °C.

Moreover, extremely small sensor designs and their high pressure and temperature stability, enable the eddyNCDT inductive miniature sensors to operate maximally in compact conditions.

The eddyNCDT 3060 eddy current measuring system is consequently being deployed on the test rig for appraising the pumps. Consequently, micrometer gap measurements can be attained, enabling precise analyses that will optimize the efficiency of axial piston pumps.

Monitoring Oil Gaps in Hydrostatic Bearings

The eddyNCDT 3060 measuring system is also tasked with superintending the oil gap in hydrostatic bearings. Hydrostatic bearings are used in large plant and machinery environments, ranging from stone mills to telescopic installations. Paying attention to the gap size in these bearings is a critical factor.

Any disruption to the hydraulics can bring about pressure drops which, in extreme cases, might cause the gap to shut, resulting in damage to the bearings and, fundamentally, system failure. To facilitate the retrofitting of older plants, it is imperative that the measuring system, which is affixed to the bearing shoe, is simple to install. Due to the extensive service life and the global use of these plants, the sensor should be easy to substitute.

As a result, non-contact eddy current displacement sensors of the eddyNCDT 3060 series are used. The measurement task is dependent on solid repeatability and exceptional temperature stability. These sensors have a robust, compact design. The plant is operated outdoors where splash oil and water are present.

Monitoring the oil gap in hydrostatic bearings is also a task for the eddyNCDT 3060 measuring system. Decisive factors for the measurement task are good repeatability and high temperature stability. These sensors have a robust, compact design.

Monitoring the oil gap in hydrostatic bearings is also a task for the eddyNCDT 3060 measuring system. Decisive factors for the measurement task are good repeatability and high temperature stability. These sensors have a robust, compact design.

Measuring the Bearing Gap in Wind Turbines

Wind turbines conventionally have two principal bearings in which the rotor shaft operates. Due to safety and cost factors, wind turbines necessitate 24/7 surveillance.

Supervising the bearing gap between the bearing surface and the drive shaft is of primary concern. An oil film in the lubricating gap restricts direct contact between the bearing surface and the shaft. Enhanced sliding properties of the bearing amplify the turbine’s efficiency while extending its service life. The sliding functions are largely contingent on the width of the bearing gap. Based on the size of this gap, judgments can be made about the wear.

This is because when the gap width is constricted, less oil coats the bearing plane and the component wear multiplies. This can trigger increased temperatures, precipitate erosion and cause fundamental bearing damage. In the worst eventuality, plant production can cease which generates hefty service costs.

To date, bearing gaps were measured during standstill. Inductive sensors based on eddy currents from MicroEpsilon acquire the measurement values during plant operation, thereby enabling reliable, cost-saving real-time analysis.

To date, bearing gaps were measured during standstill. Inductive sensors based on eddy currents from MicroEpsilon acquire the measurement values during plant operation, thereby enabling reliable, cost-saving real-time analysis.

Until now, bearing gaps were calculated during standstill based on a tactile methodology. Conversely, inductive sensors based on eddy currents from Micro-Epsilon collect the measurement values during plant operation, thereby permitting reliable, cost-effective real-time analysis. The sensors can operate in the test bench and in high volume applications. Successive use is optimal as the sensor technology can be pre-calibrated and accurately adjusted during installation and preliminary operation.

Enhanced Robustness for Industrial Environments

In opposition to regular inductive sensors, displacement sensors based on eddy currents from Micro-Epsilon are conspicuous as a result of their high precision, frequency response and temperature stability. The sensors are appropriate for use at ambient temperatures of up to 200 °C.

Moreover, the sensor and the controller are diligently temperature-compensated at the plant, enabling trustworthy measurement results even in the context of unstable temperatures. The sensors are resistant to grime, pressure and oil, which is why they offer exceptionally accurate readings in ambient pressure up to 20 bar.

The eddyNCDT 3060 system is designed for displacement and distance measurements. With more than 400 compatible sensor models, high speed and smart signal processing, the eddyNCDT 3060 product series from Micro-Epsilon defines a new performance class in inductive displacement measurement.

The eddyNCDT 3060 system is designed for displacement and distance measurements. With more than 400 compatible sensor models, high speed and smart signal processing, the eddyNCDT 3060 product series from Micro-Epsilon defines a new performance class in inductive displacement measurement.

The inductive eddyNCDT 3060 displacement measuring system offers highest application versatility since it can be easily combined with the worldwide largest sensor product range from Micro-Epsilon which comprises more than 400 compatible sensor models. Together with an outstanding price/performance ratio, this system achieves an unrivalled resolution in this field combined with high performance and maximum ease of use.

Dipl.-Ing. Stefan Stelzl, Product Manager Sensors.

This information has been sourced, reviewed and adapted from materials provided by Micro-epsilon.

For more information on this source, please visit Micro-epsilon.

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