Trakia University, Faculty of Agriculture, Department of Agricultural Engineering, 6000 Stara Zagora, Bulgaria
Tihanov, G. (2019). A study on the unloading screw operating modes of the Claas Lexion 540 and Claas Lexion 660 grain harvesters at wheat harvesting. Bulg. J. Agric. Sci., 25 (Suppl. 3), 187–191
A study has been conducted on two Claas Lexion 540 and 660 harvesters under different operating modes of the unloading screw. By chronometer, the time for emptying the cereal hopper was measured. This time in the Claas Lexion 540 harvester was reported in the three unloading modes of the grain hopper with crankshaft speed of 1031, 1650 and 2271 min-1 and Claas Lexion 660 harvester unloading was reported at nominal crankshaft speed. It was found that: (i) the actual rotation speed of the unloading screw of the Claas Lexion 540 harvester is less than the theoretical one by 6.1%-6.8% when unloading the hopper in the three unloading modes of the crankshaft at 1031, 1650 and 2271 min-1; (ii) when emptying the hopper at nominal rotation speed (2271 min-1), the actual flow rate of the unloading screw is 84% of the theoretical one, and at minimum rotation speed 1031 min-1 is 49%; (iii) the actual unloading time is 19-105% longer than the theoretical one at the at nominal and minimum crankshaft speed respectively; (iv) when unloading the hopper in motion of Claas Lexion 660 harvester, the designed flow rate was not reached, but only 84% of the unloading screw flow rate; (v) the main reason for incomplete use of the unloading system is incorrectly regulated position of the grain flow flaps.