The Design and Evaluation of an Ion-Drag Dielectric Pump to Enhance Cooling in a Small Oil-Filled Transformer

An ion-drag dielectric pump consisting of a closed loop of glass tubing has been used to investigate the pumping of transformer oil. The velocity of the oil has been measured with a multiplicity of design variables: electrode spacing and density of field enhancing points, cofield temperature gradients, waveshape, and pressure heads. The observed velocities under our experimental conditions are severalfold higher (-10x) than the flow rates computed for convective oil flow in a 25-kVA distribution transformer (=0.6 cm/s).