Significantly greater switching accuracy at the crane hoisting gear thanks to the incremental encoder FG 2

  • Modern replacement solution for mechanical overspeed switches
  • Compact design with an incremental output and overspeed switch
  • Non-adjustable switching speed, requires no programming
  • Easily swapped


A tacho generator and an additionally attached mechanical overspeed switch are responsible for speed measurements and overspeed monitoring at the hoisting gear. Due to its design the mechanical overspeed switch has a switching tolerance of ± 75 rpm, which leads to inaccuracy at the desired switching point. Moreover, the mechanical overspeed switch only reacts to speeds of 700 rpm and above. The signal quality of the tacho generator does not offer the precision required in today's world. The customer wished for a replacement solution that corresponds to current state of the art technology.


Based on the experience gained from previous modernization projects the implemented solution saw the installation of an incremental encoder FG 2 with an integrated electronic overspeed switch (option S). In addition to the incremental position value this compact encoder solution offers a factory preset switching speed. The electronic overspeed switch makes possible significantly more accurate overspeed monitoring. The switching speed of 2550 rpm was adopted from the previous solution 1:1. Not only is the overall length now distinctly shorter, this solution requires no changes to the existing mechanical interface. The entire conversion was implemented quickly and easily.

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