Design and development of a three-point hitch dynamometer.

Tractor is used as a main source of power in developing countries. In order to reduce the cost of production, knowledge of today’s complicated tools is essential. In this research, a threepoint hitch dynamometer system was fabricated for the category 0 & I tractors with the weight of 49 kg and the chassis is in a reversed U-shaped frame which allows the use of PTO at the same time. With the strain gages installed on the three sensing pins and developed five Wheatstone bridges in such a manner that, the draft forces in each link in addition to vertical forces on the lower links are measured. The dynamometer system consists of three parts including: the chassis, sensing components, and recording system. The recording system consisted of a Campbell data logger (CR10X) with a notebook computer. The dynamometer system was calibrated and several field tests were conducted to measure the force required to pull the different mounted plows. The field tests showed that the dynamometer worked well without malfunction and the system was able to provide on-line graph and save the data in the memory.