EXPERIMENTAL STUDY OF ENERGY-SAVING DRIVE OF LIQUID-PACKED RING VACUUM PUMP
The possibility of energy saving at vacuum generation in the milking plant UDS-3B is studied. Based on the experimental laboratory study at the Velikolukskaya State Agricultural Academy the experimental plant to study the energy-saving drive of liquid-packed ring vacuum pump was assembled. The rational parameters of the vacuum generator used for milking cows on pastures were substantiated. The possibility to control the rotational speed of squirrel-cage induction motors was proved immediately after their invention. This feature was implemented with the advent of power semiconductor devices - first, thyristors, and later IGBT transistors. Due to its square-law characteristic U/F and its dynamic selection, the inverter enables controlling the pump with the highest efficiency thereby reducing energy loss. The function of the dynamic characteristic U/F selection should also be mentioned. When the load on the motor shaft is reduced and, accordingly, the stator current decreases, the inverter reduces the voltage on the motor stator. On this basis, the experimental plant was developed and assembled and included the following: a liquid-packed ring vacuum pump driven by a three phase asynchronous AC motor, frequency inverter OVEN 103-4K0-V, vacuum gage pressure relay-sensor DRM-N-20, vacuum lines with 8 locks for milking unit attachment, and electric power quality analyzer UMG 96S. The experiment enabled obtaining the rational parameters of the vacuum-generator for the milking plant UDS-3B in pasture facilities.