The analysis and selection of the spinning disk system parameters for the measurement of static electrification of insulation oils

The paper presents results the aim of which was determining the most favorable conditions of ECT (electrostatic charge tendency) measurement taking of insulation oils in the spinning disk system. The work proved that a proper selection of the size and roughness of the disk surface makes the measured volume density of charge q_w independent of the hydrodynamic conditions in the measuring system on the solid and liquid phase border. Charge q_w density meets then the criterion of a material coefficient and can be used for comparing the results obtained from the systems varying in dimensions and hydrodynamic conditions. The changes suggested also ensure a high repeatability and reproducibility of the results obtained