Optimal working regime of aggregates corresponds to the speed rate at which traction is maximal, and fuel consumption is minimal. Some works cannot be done at speed rates corresponding to the optimal regime since at these rates; the moving speed of the tractor is superior to the maximum speed at which agricultural machines can move. In this case, the optimal working regime of the aggregates is limited by the technological speed of the aggregate.  During tractor exploitation, only part of the effective power of the engine is used to operate agricultural machines, the other one is lost because of the resistance forces that appear during tractor movement. In choosing a certain aggregate for a certain work, we need to take into account the main destination of the tractor or of the agricultural machines, of the possibility of making the works in agreement with agro-technical requirements, with a minimal fuel consumption and a high working capacity. The working speed of the aggregate is determined by agro-technical requirements and by the technological process of the agricultural machine. When agro-technical and technological requirements allow high-speed works with wide variation limits, working speed is chosen so that it corresponds to the maximal power of the tractor. The working caapcity of the fertiliser-spreading aggregates is largely influenced by the way in which the work is organised, since the duration of tank-filling and movements from filling points to the plot and vice-versa affects the duration of the effective work in the structure of the shift time. Tillage is the work with the highest share from the point of view of energy consumption and of the period of time tractors are used. To do the tillage, they need the highest amount of mechanical energy. Choosing aggregates for the preparation of soil for sowing is done depending on the physical and mechanical features of the soil, by soil moisture, by the land state at the time of work. In order to increase of the working caapcity of the sowing aggregates we recommend a better organisation of the works, taking into account the choice of the movement direction along the plot, the mandatory marking of the first route and the sue of markers to identify the following routes, ensuring the loading of the machines at one of the ends of the plots right on the place where the aggregate is starting working, and the supervision of seed distribution during the work.

aggregate; working width; working speed; working capacity

Presentation: oral