Channel cooling techniques for repetitively pulsed magnetic switches

Design data on cooling channel fabrication techniques, size, and geometries tailored to magnetic switches are presented. Free and forced convection channel structures suitable for magnetic switches are proposed and experimentally characterized. Magnetic core temperature data from earlier experiments are formulated into design graphs relating maximum allowable build between cooling channels to maximum core temperature and thermal generation rate. The resultant design curves are applicable to both magnetic cores and electrical windings. Practical limits on interchannel build and thermal generation for free convection are established. Effects of forced convection on the cooling capacity of a channel are discussed. Design curves are applied to a full-scale magnetic switch design. Measured temperatures in two full-scale switches are compared to model predictions. Thermal measurements from full-scale prototypes of the first two RHEPP (Repetitive High Energy Pulsed Power) magnetic switches are compared to predictions from both a simple, one-dimensional model and a more sophisticated simulation. The thermal effects due to the nonuniform current distribution in the flat winding of an actual pulsed switch are observed and discussed