A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, Resources and Development

Thesis (M.Eng.) - Asian Institute of Technology, 1994

The vibration and noise characteristics of a Siam Kubota power tiller were studied. Tests were conducted at 1000, 1200, 1400, 1600, 1800, 2000, and 2200 rpm for stationary condition and 1000, 1200, 1400, 1600, and 1800 rpm during transportation and tillage. Tests during tillage operation were conducted in dry-land conditions in Bangkok clay soil. For the measurement of vibration, three semiconductor strain gage type accelerometers were used. Accelerometers were assembled inside an aluminum casing in such a manner that they were capable of sensing vibration signals in horizontal, lateral, and vertical modes at the same time. The sound level of the power tiller was recorded. Blood pressure and heart rate of the operator were also measured. Vibration characteristics in stationary condition was found to be a complex. In general, it was observed that due to an increases in engine speed of the power tiller, the intensity and frequency of vibrations were increased. At the same operating speed and test condition, the intensity of the vibration was highest in the vertical mode and lowest in the lateral mode. The vibration intensities when compared to the ISO standard 2631, were found to exceed the standard during field operations. The sound levels of the power tiller were also compared with the International standard and were found to exceed the safe working level The operator's blood pressure and heart rate were observed to increase with an increase in engine speed and during working in severe field conditions.