Failure Mechanism of High Energy Surge Resistors

Failure mechanisms of high power noninductive ceramic resistors in high energy, and in high voltage surge applications, have been investigated. These studies have determined the fundamental cause of failure to be that of thermal shock propagation caused by the discharge of large amounts of stored energy in a short period of time. When the surge energies are maintained at low levels, peak voltages of up to 445 kilovolts can be applied to the resistors without a significant change in resistance. The test studies, in conjunction with ar approximate theoretical expression for stress of a ceramic matrix due to thermal shock, show that the failure mechanism is a functior of 1. The joules of energy stored in the discharge capacitors. 2. The physical Geometry of the resistor. 3. The physical properties of the ceramic body. 4. The resistance of the body.