When the feedback signals in actuators and in the drive mechanism are involved, the potentiometer is applicable as a cost-effective alternative to optical absolute value transmitters. In this case a gear wheel takes over the drive, whereupon depending on the application radial forces act upon the drive axle. Problem: The potentiometers are originally designed for manual adjustment. The usual axle bearings thereby do not cope with the acting forces from now on. The Megatron Elektronik AG & Co. offers modified versions in single- or multi-turn types especially for powered potentiometers. The special feature here is the economical plastic bearings, which serve as rear axle bearing in the housing and allows the sensors to last considerably longer.
This applies for instance for sheet-fed offset printing machines in newspaper production, where the 10-turn potentiometer sits basically in the so-called "ink zone drives" and "ink zone adjustment screws" respectively. There they are responsible for the feedback signal of the individual "ink adjustment element": The color tone and ink saturation can be modified by setting the ink zones. About 400 to 800 sensors are used for each ink zone according to print size. A printing machine in turn features three to four ink zones according to the number of colors. As the housing lid squarely holds the axle stub in a standard sensor without bearing, it rubs on the lid under stress and chafes the material. FGP particles can influence the sensor signals in extreme cases and dramatically reduce the service life. In the case of the sheet-fed offset printing machine, now an igus® bearing of the type "JFM-0405-03" takes over the sensor's rear axle bearing and minimizes axle play.
Potentiometric sensors are indispensable in the operation, control and monitoring of production flows. In this regard, the Megatron Elektronik offers a comprehensive range of economic products and customer-oriented options, also in small and medium quantities. Sheet-fed offset printing machines for example possess special 10-turn potentiometers with igus® bearings. As rear-side support of the sensor axles, they enhance the service life in radially loaded shafts. Even after high operational performance, no play and/or abrasion above the nominal value is identifiable that indicates a premature failure of the machine. Thus the availability of expensive printing machines can be increased by the simple modification of a low-cost part.