Power requirement of a thai-made rice combine harvester

A locally made rice combine harvester (108 kW machine) was evaluated, with a view to optimize power requirement and to incorporate necessary design Improvement. The power requirements of the machine and its main components, i.e., threshing, traction and header units were measured under no load conditions and during field operations. Results obtained from the test showed that the no load power requirement of the 108 kW machine at design speed of 1,600 rpm was 44.5 kW at the engine shaft. Threshing unit including handling and feeding system, consumed 16.9 kW (38% of total no load power), header unit 3.6 kW (8%) and hydraulic system for the traction consumed 15.5 kW (35%), respectively. The power transmission loss was estimated to be 8.5 kW (19%). The average power requirement for the whole machine during field operations at 1,600 rpm was 65 kW. The traction, threshing and header units consumed 22.8, 34.0 and 5.7 kW, respectively. The power transmission loss was 2.5 kW (4% of total operating power). Based on performance evaluation, a number of improvements in 108 kW machine were suggested which were incorporated by the Kaset Pattana Manufacturing company to increase field capacity and overcome power shortage while working on soft soils or while harvesting in a field with high plant density. The improvements included (a) replacing the 108 kW reconditioned diesel engine with a 145 kW reconditioned diesel engine; (b) incorporating fully hydrostatic drive; (c) replacing the multiple V-belt with a tooth-belt drive and (d) using a hydraulic transmission system at the header unit. Power requirement evaluation of the improved machine (145 kW machine) revealed that the no load power, requirement was 36 kW at an engine speed of 1,600 rpm. The power requirement of the whole machine during field operation at 1,600 rpm was 74.4 kW. The traction, threshing and header units consumed 25.3, 40.0 and 7.8 kW, respectively and the power transmission loss was 1.3 kW (2% of total operating power).