In-line shaft mounted
The German manufacturer NCTE develops and manufactures CAN-based in-line shaft sensors that measure torque and other forces such as shear and bending moment. Ixthus Instrumentation (UK) distributes them.
These directly-mounted sensors are especially practical for load measurement of power transmission and power take-off (PTO) shafts with real-time data acquisition. This data acquisition provides not just the operation of connected machinery but also the ability to optimize efficiency and operation for the entire drive’s function, explained the company.
NCTE sensors are designed to form part of the drive chain as a plug and play component complete with integrated signal conditioning and with no other components required. With several sized model options available torque measurement, from a zero reference, can range from 1 Nm to 10 000 Nm. The sensors provide CAN for output option.
NCTE names its measurement technology magnetostriction which is based on the magnetostrictive measurement principle. This is a physical process where the length of a body changes under the influence of an external magnetic field. By reversing this principle the sensors employ encoded magnetic fields and, as integral parts of the shaft, measure the miniscule dimensional changes directly induced on the driven shaft as torque or other physical forces. This contactless technology tracks these changes in real time over long periods of time, said the company. The sensors employ at least two opposed magnetic fields to allow error free use where external magnetic fields such as EMC interference are present – or where mechanical influences such as strong vibration and shock conditions cause shaft distortions. With protection class options of IP50 and IP65, the sensors can operate in high humidity, water, oils, and aggressive liquids used, for instance, in washdown situations.
The sensors have an operating temperature range of -40 °C to +85 °C, a torque measurement accuracy in the region of +/- 0,5%, and a shaft speeds range from 2 500 rotations per minute for the larger sized models to 10 000 rotations per minute for the smaller. Output frequency is 2 500 Hz with output options via a single electrical connector including 0 V to 10 V, 4 mA to 20 mA, as already mentioned CAN, and USB; the USB interfaced models are supplied with free of charge PC software that enables direct data display via a graphical user interface with the possibility to export data for detailed analysis.
NCTE applies its torque measurement technology across various areas of industry and research from controlling the power of e-bikes to preventative maintenance on wind turbines, and from torque measurement for motorsports to monitoring on robotic and automated medical equipment.
A particular area that demonstrates the technology and applied use of NCTE’s PTO torque sensors is that of mobile agricultural machinery where power and torque and/or bending moment and shear measurement can be optimized. Integrated between the PTO shaft of tractor and connected machinery such as powered harrows, spreaders, bailing presses etc., the sensors help to maintain the process efficiency and provide the basis for operation. In this application area NCTE’s 7000 series torque sensors can measure bi-directional torque in the region of 3 000 to 5 000 Nm at speeds up to 3 600 rotations per minute. The 7000 series can be flange mounted or supplied with a choice of optional geared shaft and bush adapter that suit the tractor, harvester, and other farm machinery PTOs. Test bench mounts are also available for research tasks, said the company.
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