The durability test of tractor hydrostatic pump type UD 25 under operating load

The results of the UD 25 hydrostatic pump durability test are presented; they were obtained in the laboratory under operating load. The test of operating load was a continuation of the hydrostatic pump durability test with a cyclic pressure loading according to the norm STN 11 9287. It lasted 300 hours, with 70°C ± 2°C of hydraulic fluid temperature. The aim of the test was to simulate the operation of the hydrostatic pump under load in laboratory and to find out its deterioration and the influence of a biodegradable fluid on its qualities. The achieved results confirmed that flow efficiency of the UD 25 hydrostatic pump decreased only to 3.6% which points to its good technical state even after the test performance. Meanwhile we can state that the used ecological hydraulic fluid on the basis of a vegetable oil “Environmentally responsible tractor transmission oil“, produced by the Slovnaft company, Inc., is characterised by very good qualities.