The gigantic bucket wheel excavators used in the field of mining are some of the largest mobile machines in the world. To ensure their interference-free operation at all times, all of the excavators’ individual components must be perfectly coordinated and able to be precisely controlled. Reliable absolute encoders play an essential role in meeting this requirement. When used in mining applications, these encoders must withstand extreme ambient conditions and comply with all stipulated safety requirements.
Precisely positioning excavator elements
A bucket wheel excavator weighing more than 1,000 metric tons consists of a steerable traversing gear in the substructure, a rotatable superstructure on which the bucket wheel boom is mounted, a bucket wheel for excavating the material and a discharging device for further transporting the excavated material. The excavator substructure and superstructure, the overall substructure and the discharging boom are each connected to slewing gears. These are required to provide high-precision values and are certified according to defined safety integrity levels (SIL). The traversing gear also needs to have high-precision position value displays.
Complete modernization by Hübner Giessen
A customer contracted us to fit its bucket wheel excavator with state-of-the-art automation and safety technology as part of a complete modernization process. We achieved this by replacing the old mechanical cam limit switches in both slewing gears, which had increased safety requirements, with absolute encoders with safety integrity level (SIL) CL3. In doing so, we eliminated the need for separate proof of functional safety. We additionally fitted the crawler gears with modern heavy-duty absolute encoders. You can take a detailed look at our modernization solution by reading our case study “Excavator / Slewing gear: AMPN 41 provides safe position monitoring at slewing gear of a bucket wheel excavator”.