Abstract: | During the function of Pelton turbines, due to the periodical changes of the temporary position betwen the water spurt and the palette having the form of a cup, the flow is unstatic and has a free surface. So, due to this specific features, a precise theoretical analise of the Pelton turbines becomes more difficult and the validation of the proposed model can be made only with the help of the dinamic identification. In the case of this type of turbine I chosed in purpose to determinate the dinamic specific features to use the periodical signals for tests and more specific the sinusoidal signal. The obtained results must be verified by experiments in purpose to validate the proposed theoretical model.Before this experiment we must take into consideration the praparation phases which means â to choose the machinery needed and to establish its characteristic and a preliminary study of the precess. Within the preliminary study must be established the orientative values of the frequency, its character and the intensity of the sources of perturbation, the aproximate structure of the transfer function, etc. Achieving the preparing phases will allow the passing way to planification and complete the experiment.Taking into consideration the details mentioned above, based on the measurments for a static treatment, I have determined the approximate shape for the transfer function.For a dinamic identification, the entrance value, which means the move of the injector needle of the turbine, must have a sinusoidal variation. This means to create an instalation that allows this variations to be obtained.This paper analises for a given case of a Pelton turbine, several solutions to obtain a sinusoidal variation of the entrance value of the process and also looks to find an optimal solution from thr point of view of the experimental spa used. |
