The diploma thesis talks about developing a measuring system in the company MEDS. It is a measuring system for measuring motor characteristics: cogging torque, friction and harmonics. In MEDS, at their day-to-day measurements they face multitude problems and challenges regarding the accuracy of measurements. Problems regarding the accuracy of measurements occur when measuring motors up to 10 min−1. Eg.: at a rotational speed of 10 min−1, revolutions fluctuate between 9.5 and 10.5 min−1 and consequently the torque measurements are not accurate enough. At higher engine rotational speeds (up to 1000 min−1) there are no problems with speed fluctuations. A potential source of problems is said to be the servo motor.
The main task was to design a measuring system consisting of different components than used in existing laboratory device. After successful assembly and programming of the CFH measurement system, the measurements began. Measurements were performed on samples X and Y.
During the measurements, focus was on the rotational speed of 10 min−1 and investigated was, whether the CFH measuring system also has problems with rotational speed fluctuations. The results of the measurements of the CFH measuring system were compared with the results of the measurements of laboratory device and it was determined whether there were really any problems with the accuracy of the measurements. On the CFH measuring system, measurements of harmonic components below 1 mNm were also performed on the tested motors. The results of the measurements were compared with the results of laboratory device and the findings stated in this diploma thesis were reached.
After asembly of the CFH measuring system, experiments of different combinations of clutches, motors and motor settings followed. The measuring systems of both devices (CFH and laboratory device) were also compared. A comparison of the measurement results showed what all affects the torque.
It has been found out that at approximately the same coupling sizes, better measurement results are achieved with bellows couplings. The best measurement results were achieved with the smallest flexible coupling manufactured by company Rudolf Huber GmBH. Interesting is, that the best measurement results were achieved with a flexible coupling and not with a bellows coupling type.
For the drive, it is better to use a suitable servo motor, which can be adjusted parametrically, to achieve the best measurement results. By using a reducer and a flywheel, the measurement results deteriorate, as the reducer brings additional frequencies to the measurement result, and the flywheel is not able to dampen the motor vibrations, transmitted along the shaft, well enough. The deterioration of the results is reflected in higher cogging torque and harmonics and new higher frequencies.
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