Calculation Improvement of Equivalent Power of Hydrostatic Drive for Crane Mechanisms

The aim of this study is to determine the analytic dependences of modifying the equivalent power of electric motors of hydrostatic drivers for different operation cycles of traveling and rotary mechanisms of lifting machines taking into account the power consumption during the idle run (when the mechanism remains immobile), which was not accounted for earlier. The latter is the novelty of this work. To achieve the goal the stand experimental studies were performed for the traveling mechanism of the bridge crane with a hydrostatic adjustable drive, the schedule status review of the electric energy consumption was carried out for all the stages of the operational cycle. The analytic dependences were defined of changing the equivalent power of the driver throughout all stages of the operational cycle, namely, acceleration, motion at a stable speed, and braking. Based on these dependences, the specified analytic expression to calculate the equivalent power for the full operational cycle was obtained, which is the most important result of the study. The significance of the result consists in that the specified calculation with the use of the proposed analytic dependences will allow using a simple method to estimate heating more objectively. It will as well enable to justify the selected power of the electric motor with the hydrostatic driver of the motion mechanisms and rotary motion of lifting machines that operate in starting-up-braking modes under conditions of varying parameters of the operational cycle.