The Effect of Electrode Temperature and Heat Capacity on the Electrical Erosion and Material Transfer for DC Switching of Electrical Contacts

Through past testing it has been observed that the endurance life of contacts tested using DC automotive type loads is better if the polarity of the test is set to use the terminal contact as the anode as opposed to using the thin contact spring as the anode. A DOE approach was used to look at the effect on contact erosion and transfer for changing the thermal characteristics of the terminal with regard to conductivity and heat capacity. An additional factor was also included for changing the polarity of the model switch to use the thin spring contact assembly as both an anode and a cathode to compare that effect on the erosion and transfer. The DOE also included two DC voltage levels and two different silver alloys as factors. The design is a two level four factor matrix which includes 16 experiments. The results are explained with model graphs showing the LSD ( least significant difference) for the responses among the factors and interactions among the factors.